Table of contents :

• implantation of freshly isolated or cultured cells : individual cells or small cellular aggregates from the patient or a donor are either injected into the damaged tissue directly or are combined with a degradable scaffold in vitro and then implanted.
• in situ tissue regeneration : a scaffold implanted directly into the injured tissue stimulates the body's own cells to promote local tissue repair. The construction of stable blood vessels is a fundamental challenge for tissue engineering in regenerative medicine. Engineered blood vessels have often been found to be immature and unstable^ref
• genes that enhance the survival and/or proliferation of vascular cells - endothelial cells and mural cells - can be introduced to extend the lifespan of the engineered vessels^{ref1, ref2, ref3}, but these may prove to be oncogenic.
• a network of blood vessels stable and functional for one year in vivo can be formed in mice by co-implantation of human umbilical-vein endothelial cells (HUVECs) and 10T1/2 mesenchymal precursor cells in a 3D fibronectin-type I collagen gel^ref. The 10T1/2 cells differentiate into mural cells though heterotypic interaction with endothelial cells^{ref1, ref2, ref3}. To permit continuous observation of the engineered vascular networks in vivo, a 3D construct was implanted in mice bearing transparent "windows"^ref and the gene for EGFP was introduced in order to track the implanted HUVECs^ref. The likely existence of endothelial and of smooth-muscle progenitor cells in adults^{ref1, ref2} indicates that these cells might serve as a source of autologous cells for engineering blood vessels by using the approach described here.
• implantation of tissues assembled in vitro from cells and scaffolds (tissue engineering) : a complete 3D tissue is grown using patient or donor cells and a scaffold, and then is implanted once it has reached "maturity"

• implants : without restablishing vascular and nervous connections
• avascular graft / white graft : a graft of tissue in which not even transient vascularization is achieved
• corneal allograft
• full-thickness corneal allograft (lasting 30-40')
• penetrating graft
• lamellar allograft preserving Descement's membrane and corneal endothelium in recipient's cornea (lasting 2 hr)
As the cornea is not vascularized transplant rejection occurs in less than 5% of recipients and can be prevented with topical corticosteroids. Rejection is more frequent when cornea has become vascularized (eg. in herpetic keratitis). Quality directly relates with number of endothelial cells. Cornea can be included in a conservation medium (eg Optisal^®) for up to 1 week or in a culture medium for up to 1 month. A punch is used to cut a circular fragment from the donor cornea and a suction mechanical trapane is used to remove a same fragment from the recipient's cornea. The suture is left for 1 year^ref.
• dental implant : a prosthetic device of alloplastic material implanted into the oral tissues beneath the mucosal or periosteal layer or within the bone to provide support and retention to a partial or complete denture.
• endosseous implant / endosteal implant : a dental implant made of metal or sometimes ceramic or polymeric material, consisting of a blade, screw, pin, or vent, inserted into the jaw bone through the alveolar or basal bone, either directly or through the root canal and apex of a tooth, with a post protruding through the mucoperiosteum into the oral cavity to serve as an abutment for dentures or orthodontic appliances, or to serve in fracture fixation.
• endodontic implant : a metallic implant extending through the root canal of a tooth into the periapical bone structure, thereby lengthening the root of a pulpless tooth.
• intraperiosteal implant : a frame that conforms to the shape of the jawbone and is implanted beneath the outer or fibrous layer of the periosteum so that it rests firmly on the bone, with a post protruding into the oral cavity to serve as an abutment for dentures; used most commonly for upper fixed partial dentures and in the treatment of cleft palate.
• osseointegrated implant : an endosseous implant containing pores into which osteoblasts and supporting connective tissue can migrate. Metallic, ceramic, and polymeric materials have been used.
• Brânemark implant : a type of osseointegrated implant consisting of a two-stage system of titanium screws
• subperiosteal implant : a dental implant consisting of a metal frame implanted under the periosteum and firmly bound by the mucoperiosteum, resting on the jaw bone, with a post protruding into the oral cavity; used most commonly as an abutment for upper fixed partial dentures and in the treatment of cleft palate.
• transmandibular implant : a dental implant consisting of baseplate, cortical screws, threaded posts, and a superstructure that attaches to a denture, inserted via submandibular incision and fixed to the symphyseal border. The implant transverses the mandible, bears the denture directly, and is designed for patients with severe mandibular alveolar atrophy.
• Bosker implant : a common type of transmandibular implant.
• transosteal implant : a dental implant consisting of a bolt that crosses the mandible and is secured in place by a nut; a post protrudes into the oral cavity and serves as an abutment for dentures or orthodontic appliances.
• transplantations and transfusions : reestablished vascular and nervous connections

Donor and recipient : warm ischemia time (from arterial clamping to placement into cold organ perfusion solution) => cold ischemia time (CIT) (from placement into cold perfusion solution to beginning of vascular anastomoses in the recipient) => second warm ischemia (from beginning of vascular anastomoses to arterial declamping in the recipient)
• autotransplantation / autotransplant / autograft / autochthonous, autogenous or autologous graft (if the donor is the recipient itself : e.g. bone marrow, skin, ovary, spleen, parathyroid, fatty tissue, ...)
• syngeneic transplantation / syngraft / isograft and isogeneic, isologous, or syngeneic graft / isotransplantation : a graft between genetically identical individuals. Typically, syngrafts are grafts between monozygotic twins, between animals of a single highly inbred strain, or between F₁ hybrids produced by crossing inbred strains. Since there is only 1 twin pregnancy every 270 births, syngeneic transplant is a rare event.
• allogeneic transplantation / allotransplantation / allotransplant / allograft / homograft / homologous or homoplastic graft (if the donor belong to Homo sapiens species) : transplantation of an allograft; the 3 types are
• cadaveric donor transplantation : allogeneic transplantation of an organ or tissue from a cadaver
• grafts from heart-beating donors (HBDs) : heart => lungs => liver => pancreas => kidneys

Techniques :
• no touch fast technique (sequential surgical equipes) : median sternotomy => preparation of arteries; median xiphopubic laparotomy (also transverse incision in obese patients); preparation of inferior vena cava => exploration of abdominal cavity => cannulation of subrenal abdominal aorta and inferior vena cava in hemodynamically unstable patients; isolation of choledocus, hepatic artery, gastroduodenal, right gastric artery and subhepatic vein for liver explantation => ligation of inferior mesenteric artery => isolation and cannulation of inferior mesenteric vein for portal perfusion => cholecystotomy and lavage of bile from abdominal cavity with NS to prevent autolysis and liver damage => heparinization (3 mg/kg i.v.) (when the heart is explanted, phenothiazines cannot be administered) => placement of angiostat over supradiaphragmatic aorta and superior vena cava => discontinuation of systemic i.v. fluid infusion => cold perfusion with EW through subdiaphragmatic aorta (and, if portal vein is perfused, also through inferior mesenteric vein) => cardiectomy and pneumonectomy. Cooling of abdominal viscera can be enhanced by introduction of sterile ice into the abdominal cavity => ligation of right gastric and gastroduodenal artery and isolation of common hepatic artery until celiac trunk => pancreatectomy (the choledocus is sutured at the upper border of pancreas) and hepatectomy together with celiac trunk. Nephrectomy is performed at last. Incision of right parietocolic pouch => medial mobilization of ascending colon and terminal ilium => distal ligation of superior mesenteric artery => aortic clampage and cold perfusion => mobilization of asceding colon and sigma by incision of left parietocolic pouch along Toldt white line => ligation of inferior mesenteric vessels => kydneys are made free from retroperitoneum and psoas but still into Gerota's capsule (which is then removed at the bench). Ureters are sectioned just above the cupule of the urinary bladder to prevent excessive traction. Periureteral adipose tissue has to be preserved in the golden triangle (from distal ureter to lower renal pole) as the ureteral artery (emerging from the lower border of the renal artery) is the only one left for vascularization of ureter. For en-bloc explantation the left kidney and ureter are passed through an incision in the mesocolon. Aorta and inferior vena cava are sectioned distally to perfusion cannulas after looking for eventual lower polar arteries emerging from common iliac artery. The large vessels (still cannulated) and ureters are moved upward  => the posterior lumbar vessels are ligated and dissected => section of aorta and inferior vena cava just below diaphragm. At the bench the left renal vein (longer) is sectioned, while the right renal vein (shorter) is left attached to the inferior vena cava (sectioned just above the entry of the right renal vein and then used to enlenghten the right renal vein itself). The posterior face of the aorta is incised longitudinally between emergence of lumbar arteries beginnig from proximal aorta and respecting eventual anomal renal arteries. An aortic patch including the celiac trunk and the superior mesenteric artery is cut; a trasverse incision between the ostium of the superior mesenteric artery and the ostium of the renal arteries; a second transverse incision is practiced over aorta downstream of renal arteries to leave a wide patch around them. The 2 kidneys are then separated by a longitudinal incision in the anterior wall of the aorta between the ostium of the right and left renal arteries. The iliac arteries and veins are explanted en bloc leaving bifurcations intact : even the 2 larger saphena veins are explanted sectioning them 2 cm below the knee, as they could be useful for eventual successive vascular reconstructions at the bench in renal or other organ transplantation.

Complications :
• excessive resection of subhepatic vena cava and damage to right renal vein
• injury to eventual multiple renal vessels emerging from iliac arteries
• too wide resection of aortic patch by the liver surgeon damaging right renal artery
• total abdominal evisceration (TAE) (Nakazato : 2 surgeons required) : preliminary dissection performed by the surgeon and physician's assistant averaged 30 to 45 minutes before aortic cross-clamping. Removal of all abdominal organs (liver, kidneys, pancreas, bowel) en bloc averaged 16 to 24 minutes after aortic cross-clamping, depending on the speed of the thoracic procurement.^ref
• grafts from non-heart beating donors (NHBDs) preserving some brainstem functions

Techinique : a catheter is introduced in the femoral artery to make a fast cold perfusion contemporaneously administering heparin. After clamping of thoracic aorta, the kidneys are rapidly removed en bloc and separated at the bench
• [brephoplastic graft : the transplantation of tissue from an embryo or newborn to an adult animal]
In the early 1960s, cadaveric donations were thought to be impractical and impossible. Living donors were the only available source of organs for transplantation. At Massachusetts General Hospital, a liver was harvested from a police officer whose heart was beating but whose brain was deemed dead. This seminal event led to the development of the concept of brain death as death, rather than the cessation of circulation, which previously defined death. The concept of brain death greatly increased the number of organs available for donation and improved the preservation of harvested organs. Once the concept of brain death was established, a system for organ procurement was founded to ensure the quality and availability of organs as efficiently as possible.
Contraindications : well-differentiated thyroid papillary carcinomas > 1 cm in diameter, as well as follicular and medullary carcinomas (regardless their size and or clinical staging), present absolute contraindication to donation. Papillary microcarcinoma restricted to the thyroid gland (with no metastases in local lymph nodes) because of its specific behavior and almost always benign course, requires an individualized approach. It seemed that when a recipient is in a life-threatening condition, we should consider taking organs from a donor suffering of papillary microcarcinoma restricted to the thyroid gland.
• living donor transplantation : antiplatelet drugs should be discontinued 2 weeks before; oral contraceptives 6 weeks before; antihypertensive drugs should be reduced; the donor should by hydrated 2 hours before explantation to ensure a diuresis > 80-100 ml/hr; a broad-spectrum antibacterial (2nd or 3rd-generation cephalosporin) is administered and the lower limb are covered with elastic bandage to prevent PE from DVT.
• living related donor (LRD) transplantation / syngenesioplastic transplantation : allogeneic transplantation in which the donor and the recipient have a close biological relationship, such as that of a mother and her child or a brother and sister. With directed donation to loved ones or friends, worries arise about the intense pressure that can be put on people to donate, leading those who are reluctant to do so to feel coerced. In these cases, transplantation programs are typically willing to identify a plausible medical excuse, so that the person can bow out gracefully^ref. Equally important, however, are situations in which people feel compelled to donate regardless of the consequences to themselves. In one instance, both parents of a child who was dying of respiratory failure insisted on donating lobes of their lungs in a desperate but unsuccessful attempt to save her life (Kolata G. Lungs from parents fail to save girl, 9, and doctors assess ethics. New York Times May 20, 1991:A11). Such a sense of compulsion is not unusual. In cases like these, simply obtaining the informed consent of the relative is insufficient — physicians are obligated to prevent people from making potentially life-threatening sacrifices unless the chance of success is proportionately large.
• living nonrelated or unrelated donor (LNRD / LURD) transplantation : allogeneic transplantation in which the donors choose to give to a specific person with whom they have no prior emotional connection. This type of donation usually occurs when a patient advertises for an organ publicly, on television or billboards or over the Internet. Such advertising is not illegal, but it has been strongly discouraged by the transplantation community. 2 central objections are that the practice is unfair and that it threatens the view that an organ is a "gift of life," not a commodity to be bought and sold. Some argue that just as we have a right to donate to the political parties and charities of our choice, so should we be able to choose to whom to give our organs. In practice, however, this means that those who have the most compelling stories and the means to advertise their plight tend to be the ones who get the organs — rather than those most in need. This strikes some ethicists as unfair. Unlike monetary gifts, they argue, organ transplantation requires the involvement of social structures and institutions, such as transplantation teams and hospitals. Hence, the argument goes, these donations are legitimately subject to societal requirements of fairness, and transplantation centers should refuse to permit the allocation of organs on the basis of anything but morally relevant criteria^ref. The most ethically problematic cases are those in which the recipient is chosen on the basis of race, religion, or ethnic group. In one case, for example, the family of a brain-dead Florida man agreed to donate his organs — but insisted that because of the man's racist beliefs, the recipients must be white. Although the organs were allocated accordingly, Florida subsequently passed a law prohibiting patients or families from placing such restrictions on donation (Veatch RM. Transplantation ethics. Washington, D.C.: Georgetown University Press, 2000). Even when the motives for choosing a recipient may be unethical, however, there might be reasons for allowing the donation to proceed. Consider a case that was discussed at a recent public forum hosted by Harvard Medical School's Division of Medical Ethics: a Jewish man in New York learned of a Jewish child in Los Angeles who needed a kidney transplant. The man wanted to help someone of his own faith and decided he was willing to donate a kidney to help this particular child. Despite his discriminatory preference, one might view the donation as permissible, since at least some patients would benefit (the child would receive a kidney, and those below her on the waiting list would move up one notch) and no one would be harmed (those above the girl on the waiting list would not receive the kidney under any circumstances, because the man would not give it to them). Whether directed donation to strangers violates standards of fairness is thus controversial. But if it is permitted, it will be very difficult to prohibit discriminatory preferences, since donors can simply specify that the organ must go to a particular person, without saying why. The other substantial cause for concern about this type of donation is its potential for making possible the buying and selling of organs (see also organ trade). These practices are strictly prohibited by law, yet they seem to be an inherent risk in directed donations to strangers. Wealthy patients in need and healthy donors looking for a quick fix to their financial problems will always be able to find ways around even the most earnest attempts to prevent money from changing hands. Despite these concerns, efforts to direct organ donations to strangers are not new, dating back at least to the celebrated 1982 case of Jamie Fiske, whose father successfully mounted a nationwide appeal for someone to donate a liver to her. Today, many such solicitations are transmitted over the Internet, where, when the practice was relatively limited, organ solicitation was managed quietly, on a case-by-case basis, by individual transplantation centers. All this changed, however, with the emergence in 2004 of MatchingDonors.com (as discussed by Steinbrook in this issue of the Journal, pages 441–444). This Web site currently claims to have > 2100 registered potential donors and to have brokered 12 transplantations, with about 20 more recipient–donor pairs matched and awaiting surgery. Although the business conducted on this organization's Web site does not raise any fundamental ethical issues not already posed by other methods of solicitation, it does introduce a new degree of visibility that increases the magnitude of the issue. Will competing commercial Web sites begin to emerge? How will these sites be held accountable? Dr. Jeremiah Lowney, the medical director of MatchingDonors.com, recently argued that just as a dating service could not be held responsible for a bad date, his Web site has no responsibility for the outcomes of its matches. Furthermore, the Web site has no mechanism for ensuring the quality of the information it provides about transplantation and donation by living persons or for checking the accuracy of information submitted by potential donors and recipients. Given the life-or-death consequences of the procedure, organ donation should not be governed by the ethics of caveat emptor. Nevertheless, MatchingDonors.com has clearly identified a need, and if this need is not met by a service that can address the ethical challenges, the vacuum will be filled by other enterprises. Entrepreneurs commonly open up useful new markets and services that must eventually become subject to rigorous standards and regulations. The solicitation of organs over the Internet is probably here to stay, but it will require higher standards of responsibility and accountability than are currently in place. UNOS has > 20 years of experience in managing the cadaveric-donor pool and is in a good position to extend its jurisdiction to include donation by living donors. The organization recently considered the topic of solicitation and decided not to pursue building a Web site similar to that of MatchingDonors.com but, instead, to provide educational information for anyone who is willing to be a living donor of a kidney and to develop a nationwide mechanism for allocating organs for nondirected donation by living donors. This effort, however, does not go far enough. The proposal does not address directed donation and leaves many critical aspects of donation by living donors to the transplantation centers. Organ transplantation is big business, and each center is highly motivated to expand its share of the pie. They therefore have intolerable conflicts of interest when it comes to regulating themselves. Instead, UNOS should be charged with standardizing the process for evaluating potential donors, ensuring that independent advocates are assigned to help donors make an informed choice, developing mechanisms to deal with potential injury or death to the donor, setting standards for both directed and nondirected donation, and prohibiting transplantation when the chance of success is insufficient to justify the risks. Comprehensive oversight is necessary if the ethical pitfalls are to be adequately addressed^ref
• nondirected donation, in which the donor gives an organ to the general pool to be transplanted into the recipient at the top of the waiting list. The radical altruism that motivates a person to make a potentially life-threatening sacrifice for a stranger calls for careful scrutiny. One recent case involved a man who seemed pathologically obsessed with giving away everything, from his money to his organs, saying that doing so was "as much a necessity as food, water, and air." (Parker I. The gift: Zell Kravinsky gave away millions: but somehow it wasn't enough. The New Yorker. August 2, 2004:54-63). After donating one kidney to a stranger, he wondered how he might give away all his other organs in a dramatic suicide. Other psychologically suspect motivations need to be ruled out as well. Is the person trying to compensate for depression or low self-esteem, seeking media attention, or harboring hopes of becoming involved in the life of the recipient? Transplantation teams have an obligation to assess potential donors in all these dimensions and prohibit donations that arouse serious concern^ref.
Donable tissues : kidney, liver segment II, lung lobe, left pancreas, pancreatic islets
Epidemiology : today, according to the United Network for Organ Sharing (UNOS), almost half of all kidney donors in the USA are living. In 2004, living organ donors also provided a lobe of the liver in approximately 320 cases and a lobe of a lung in approximately 15 cases^ref.
Such grafts are invariably rejected unless the recipient is immunosuppressed, or the graft is to an immune-privileged site.
Click here for pathogenesis of transplant rejection.
Click here for danger theory.
Click here for Italian laws
Criteria for assignation :
• age
• compatibility
• human blood groups
• Rh group doesn't matter
• AB0 group : donor 0 to recipient 0 and B, donor A to recipient A and AB, donor AB to recipient AB, donor B to B and AB
• HLA types (HLA-A, HLA-B, HLA-DR), and MHC typization tools
• waiting time
Common contraindications for donors :
• cancers (breat cancer in females, prostate cancer in males), but nonmelanoma skin cancers is not a contraindication
• sepsis and infection from an antibiotic-resistant pathogen (body cooling impairs detection of many species), but localized infection at other body site is not a contraindication
• viral infections : HBV, HIV-1 patients may receive organs only in pilot programs, HCV patients may donate liver only for fulminating hepatitis, HHV-4 / EBV, HHV-5 / CMV, HHV-3 / VZV should be monitored
• some countries prevent inmates from donating organs
Overall donor risk :
• standard risk
• augmented risk : e.g. episodic finding of drug of abuse
• calculated risk : e.g. time elapsed since cancer remission
• unacceptable : e.g. HIV patients
• xenogeneic transplantation / xenotransplantation / xenotransplant / xenograft / heterograft / heterotransplantation / heterologous or heteroplastic graft (if the donor belongs to a species different from Homo sapiens)

"The dream of the ancients from time immemorial has been the junction of portions of different individuals, not only to counteract disease, but also to combine the potentials of different species. This desire inspired the birth of many mythical creatures which were purported to have capabilities normally beyond the power of a single species. The modern world has inherited these dreams in the form of the sphinx, the mermaid and the chimerical forms of many heraldic beasts." (Christiaan Barnard, 1967)^ref
History : because of the lack of donor organs, the use of biomechanical and nonhuman organs is being explored as a potential solution to this shortage. Xenotransplantation was actually performed long before clinical allotransplantation. In 1905, French surgeon Princeteau transplanted a slice of rabbit kidney into a uremic child. Despite noted improvement of renal function, the child died of pneumonia. Although many other examples of xenografts of different organs have been reported from this early period, human xenografts were quickly abandoned because they uniformly failed. More recently, in 1960, Reemtsma performed a kidney transplantation from a chimpanzee donor into a human recipient; aggressive immunosuppression led to a 9-month survival. In 1984, Bailey performed an orthotopic transplantation of a baboon heart into a human neonate with a hypoplastic left ventricle; the graft functioned for 20 days. Despite aggressive immunosuppression, graft failure occurred secondary to vascular rejection. A baboon-to-human liver transplantation was performed by Starzl in 1993. This graft functioned well for a time, although the patient died several months later from severe sepsis and organ rejection. Other xenotransplant efforts include transplantation of dopaminergic porcine fetal neural cells to the basal ganglia in order to treat Parkinson disease. Deacon et al performed one such transplantation in 1997. Cellular xenografts, such as pancreatic islet cell transplantation and neural cell transplantation, may be protected from rejection because of the absence of vascular tissues. In contrast, xenotransplantation may, in the future, be used as a lifesaving procedure for critically ill patients who are waiting for allografts but are dying because of the shortage of organs. This technique may be particularly helpful for patients with acute liver failure or cardiac failure^{ref1, ref2}
Hurdles to clinical xenotransplantation :
• size and function. Studies in which pig organs have been transplanted into nonhuman primates indicate that the kidneys,hearts, and lungs of pigs would function sufficiently well in a human to sustain life. By contrast, presumed incompatibilities between the complex metabolic systems of the pig and human liver would seem to preclude ready application of hepatic xenotransplantation. However porcine liver xenografts can function adequately in baboons, and pig hepatocytes have been observed to sustain the life of rats with cirrhosis. Even if physiological hurdles were found to be a barrier to xenotransplantation, genetic engineering could be applied to the roblem.
• immunotolerance can be established because the amount of nonspecific immunosuppression required to protect the organs from rejection would be clinically intolerable. The immune responses to xenotransplantation are much more severe than the immune responses to allotransplantation for at least 3 reasons :
• all individuals have innate immunity agains xenogeneic cells, and this innate immune response recruits adaptive immune responses against the graft mediating hyperacute rejection.
• xenogeneic transplants carry a diverse set of foreign antigens against which cellular and humoral immune responses can be elicited (in allotransplants, by contrast, the main foreign antigens are MHC antigens)
• immune regulation, which might partially control responses to allograft, might fail to do so in responses to xenografts
As the biological barriers to xenotransplantation depend, to a significant extent, on the way in which the graft is connected to the recipient, it is importtant to distinguish between
• isolated cell xenotransplants are nourished and maintained by the microenvironment, growth factors and ingrowth of capillaries of the recipient. On the other hand tissue xenotransplants are maintained by both donor and recipient growth factors, and have a mixed vascular supply, consisting of in-grown blood vessels of recipient origin and blood vessels formed by the spontaneous anastomosis of donor and recipient capillaries. In both cases xenotransplant failure may be due to
• primary non-function :
• inability of growth factors of the recipient to support newly implanted cells and/or failure of graft factors to support angiogenesis by host vessels.
• action of NK cells or recently activated T lymphocytes on the newly implanted graft
• action of complement on xenogeneic cells and tissue introduced into the blood (for example, pancreatic islets injected into the portal vein)
• cellular rejection
• whole-organ xenograft are connected to the recipient by anastomosis of large blood vessels of the donor and recipient. As aside from this connetion, the graft remains entirely of donor origin, organ xenografts are not generally compromised by incompatibility of the local environment in which they are placed and xenotransplant failure may be due to
• hyperacute rejection : the a-gal epitope (Gala1-3Galb1-(3)4GlcNAc-R) is abundantly synthesized on glycolipids and glycoproteins of non-primate mammals and New World monkeys by the glycosylation enzyme a1,3galactosyltransferase (a1,3GT). In humans, apes and Old World monkeys, this epitope is absent because the a1,3GT gene was inactivated in ancestral Old World primates. Instead, humans, apes and Old World monkeys produce the anti-Gal natural antibodies (nAb), which specifically interacts with a-gal epitopes and which constitutes approximately 1% of circulating immunoglobulins. Anti-Gal has functioned as an immunological barrier, preventing the transplantation of pig organs into humans, because anti-Gal binds to the a-gal epitopes expressed on pig cells. Binding of xenoreactive nAb to Gala1-3Gal activates complement and rapid insertion of terminal complement complexes in the cell membranes of the endothelial lining of blood vessels in the donor organ, which in turn causes graft destruction^ref. Approaches to prevention of hyperacute rejection include :
• xenoreactive antibodies (XA) can be depleted by column absorption
• complement can be inhibited by Cobra venom factor or soluble CR1 (sCR1), or genetic engineering of donor organs for the expression of the species-specific human complement-regulatory proteins DAF, CD59 / MIRL, and MCP.
• NK cells
• genetic engineering of a-1,3-galactosyltransferase 1 (GGAT1)^-/- pigs to eliminate Gal-a-1,3-Gal epitopes has become possible with cloning technologies. Anyway eliminating an antigen by gene targeting might uncover new epitopes!
• kidneys from GGAT1^-/- pigs enabled 8 baboons to survive for up to 81 days, compared with around 30 days for non-transgenic kidney (the longest that researchers have extended a baboon's life with a pig organ — although baboon-to-baboon transplants are still more successful). Along with the kidney, the researchers also transplanted pieces of pig thymus, which pump out immune cells that do not attack pig tissues.
• acute vascular rejection is caused by xenoreactive antibodies which bind to the xenograft causing activation of endothelium in the graft and possibly apoptosis. Approaches to prevention of acute vascular rejection include :
• pre-transplant infusion with donor haemotopoietic cells induces tolerance to Gal-a-1,3-Gal and other xenospecific antigens
• grafting donor bone marrow or stem cells, but the biological hurdles to engraftement of xenogeneic bone marrow cells, which include the action of antibodies and complement on the cells and the incompatibility of host growth factors, might make induction of tolerance to organ xenografts difficult to achieve.
• grafting donor thymus into initially immunocompetent recipients that are thymectomized and treated with T cell-depleting Abs allows reconstitution of the CD4 compartment, and these donor CD4 cells are rendered tolerant to donor-specific tissue. These hosts appear to have normal immunocompentece, in that they are capable of clearing opportunistic infections and responding to protein Ags presented by recipient class II MHC molecules. The donor thymus is not required to produce more T cells than normal syngeneic thymus to maintain a constant peripheral CD4 cell pool.
• knock-out of a-1,3-galactosyltransferase 1 (GGAT1) and possibly other pig genes to decrease antigen expression has become possible with cloning technologies. Anyway eliminating an antigen by gene targeting might uncover new epitopes !
• suppression of pro-coagulant or pro-inflammatory genes inhibits endothelial cell activation
• accommodation, an acquired resistance to humoral immune-mediated injury, has been induced by transient depletion of xenoreactive antibodies followed by the return of those antibodies without causing humoral rejection. In this setting, accommodation might be brought about by
• a change in xenoreactive antibodies
• a change in the antigens in the graft
• binding of xenoreactive antibodies or the action of inflammatory agonists, in subtoxic amounts induces changes in the graft, which make the graft inured to humoral injury.
• desensitization or loss of receptors for inflammatory agonists
• interruption of cell activation or effector pathways - for example, by IkB or BCL2
• production of proteins, such as CD59 / MIRL or haem oxygenase 1 (HO-1) that repair or block the detrimental effects of the agonists that would otherwise induce tissue injury
• cellular rejection
• chronic rejection : if it is caused by an immune response to the graft, as some experimental evidence indicates, then it should be common and severe in xenotransplants. If it is caused by qualities of the graft, such as preservation time, ischaemia and donor age, then it should not be much of a problem. In any case, because xenotransplantation offers an unlimited supply of organs, the impact of chronic rejection might be less serious as the chronically rejected organ can be replaced
• donor infectious organisms :
• chimpanzees (Pan troglodytes) : theoretically transmittable viruses
• simian immunodeficiency virus (SIV)
• cercopithecine herpes virus 1 / herpes virus B
• simian cytomegalovirus (SCMV)
• simian fomay virus
• monkeypox virus
• pigs (Sus scrofa) : the risk of the spread of pathogens should be less in xenotransplantation than in allotransplantation, because most pathogens of pigs do not infect humans, and because pigs can be raised to be free of known human pathogens. All pigs carry porcine endogenous retrovirus (PERV), but its potential effects on people are unknown and to date it has not been found to be transmitted to humans (strain A uses as receptors HuPAR-1 and HuPAR-2). In a model of human-pig chimerism, some human HSCs engrafted in pigs contain both human and porcine chromosomal DNA. These hybrid cells divide, express human and porcine proteins, and contribute to porcine nonhematopoietic tissues. In addition, the hybrid cells contain porcine endogenous retroviral DNA sequences and are able to transmit this virus to uninfected human cells in vitro. Thus, spontaneous fusion can occur in vivo between the cells of disparate species and in the absence of disease. The ability of these cell hybrids to acquire and transmit retroviral elements together with their ability to integrate into tissues could explain genetic recombination and generation of novel pathogens^ref.
• cows (Bos taurus)
Strategies :
• nuclei from a human patient might be transferred to enucleated stem cells of an animal, and the cells might then be grown in vitro or in an animal to generate differentiated human tissue that is autologous with the patient.
• pig embryonic tissues represent an attractive option for organ transplantation. However, the achievement of optimal organogenesis after transplantation, namely, maximal organ growth and function without teratoma development, represents a major challenge. Distinct gestational time windows were determinated for the growth of pig embryonic liver, pancreas, and lung precursors. Transplantation of embryonic-tissue precursors at various gestational ages [from E (embryonic day) 21 to E100] revealed a unique pattern of growth and differentiation for each embryonic organ. Maximal liver growth and function were achieved at the earliest teratoma-free gestational age (E28), whereas the growth and functional potential of the pancreas gradually increased toward E42 and E56 followed by a marked decline in insulin-secreting capacity at E80 and E100. Development of mature lung tissue containing essential respiratory system elements was observed at a relatively late gestational age (E56). These findings, showing distinct, optimal gestational time windows for transplantation of embryonic pig liver, pancreas, and lung, might explain, in part, the disappointing results in previous transplantation trials and could help enhance the chances for successful implementation of embryonic pig tissue in the treatment of a wide spectrum of human diseases^ref.
Web resources :
• Swine Leukocyte Antigen Database (SLAD)
• Bovine Leukocyte Antigens
Click here for ischemia reperfusion injury (IRI)
Placements :
• homotopic or orthotopic transplantation : transplantation of tissue from a donor into its normal anatomical position in the recipient.
• heterotopic transplantation :
• kidney transplantation
• experimental transplantation of tissue typical of one area to a different recipient site, usually a non-immune-privileged site
• subcutaneous tissue
• subcapsular space of the kidney
• mice given transplanted testicle tissue on to the backs are capable of growing mature goat, pig and monkey sperm 7 months later : this may one day help to preserve endangered species.
Good tissue practices (GTP) rule.
Transplanted material :
• cell transplantations (cell therapy)
• infusion graft : transplantation by injection of a suspension of cells
• adoptive transfer or adoptive immunization => adoptive immunity
• differentiated cells
• CNS neurons
• focal or regionally restricted neurologic diseases
• Parkinson's disease (PD) : the goal has been the engraftment and enhanced survival of dopamine-producing cells within the striatum, or by forestalling degeneration of dopaminergic neurons within the substantia nigra (SN). Anyway differentiated dopaminergic neurons don't survive after transplantation and some are rejected by the immune system. All strategies here reported didn't result in life quality improvement in double blind placebo-controlled trials even if neurons are alive and dopamine producing.
• xenogeneic pig neurons
• dopamine-producing cells from patient's own adrenal glands
• neurons from aborted fetuses (15-50% developed dyskinesias caused by overactive or poorly functioning neurons)
• dopaminergic neurons derived from cloned ES cells by
• transfection with a CMV plasmid driving expression of Nurr1 (a transcriptional factor involved in the differentiation of midbrain precursors into dopamine neurons)
• cell culture system that allows rapid and efficient derivation of most nervous system neural subtypes
• widely disseminated (in the brain and/or spinal cord) neurologic diseases (lysosomal storage diseases (LSD), leukodystrophies, inborn errors of metabolism, hypoxic-ischemic encephalopathy, Alzheimer's disease (AD), Huntington's disease (HD), multi-infarct dementia (MID), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), glioblastomas) : they have not typically been regarded as within the purview of neural transplantation
• transplantation of somatic cells derived from the hematopoietic system administered via bone marrow transplantation (BMT), with unsatisfactory results
• autologous skin cells genetically modified to express NGF when injected stereotaxically in up to 10 million numbers into 10 different brain sites they halve Alzheimer's disease (AD) patients' rate of mental decline 1 year on (by comparison, the best drug therapies offer only around a 5% decrease in the rate of decline) : brain scans also showed that the patients had more blood pumping around their brains than before their surgery, indicating that the injected cells were still alive and having an effect one year later. Skin cells are easy to obtain, culture and alter genetically and replicate when given space to grow in culture but stop dividing when they are implanted in the dense tissue of the brain, meaning that they are unlikely to form tumours : over time the transplanted cells may slow their production of NGF and be less effective
• neonatal pig choroid plexus cells encapsulated in alginate expressing neurotrophins has shown beneficial effects in rat^ref and primate models (225 nmol quinolinic acid injection in the ipsilateral striatum) for Huntington's disease (HD). Living Cell Technologies (LCT)'s (Auckland, New Zealand) BioPharma subsidiary in Providence, Rhode Island, which plans to carry out the human trials.
Glial scarring prevents implantation of transplanted neurons in both brain and retina.
• blood cells : the National and regional register of blood and plasma, established in 1991, makes it possible to know the production and distribution of blood and blood components in Italy. It represents an important instrument to programme the blood needs. The Register is filled out by every Transfusion Service (302 in 2004), according to the standard questionnaire established in the Minister Decree of 1996, it is sent to the relative Regional Health Board and, by this, to the Istituto Superiore di Sanità (the Italian National Institute of Health). The Register is essentially divided into two sections: the first one collects data concerning donors, donations, and plasma; the second one checks other important activities for the transfusion service (laboratory diagnostics, computerisation, quality controls, and committees for the good use of blood). In 2004 total donors were 1,451,641, blood donations were 2,274,513, and donations by aphaeretic procedures about 400,000. The amount of plasma produced was 725,112 litres, 531,395 of them were sent to industry for plasmaderivatives production. About 80,000 units of red cells were exchanged between regions to satisfy the national need^ref.

Donors : every people aged 18-60 and weighing > 50 kg, with SBP = 110-180 and DBP = 50-100, can donate blood. Multicomponent blood donation (MCBD). Exclusions may be :
• temporary :
• pregnancy (1 year)
• abortion (1 year)
• menstruating women
• gastric ulcer or duodenal ulcer
• hypersensitivities
• vaccination and/or prophylaxis :
• anti-malaria vaccination (3 years)
• anti-polio vaccination (14 days)
• yellow fever vaccination (14 days)
• drugs :
• NSAIDs (5 days)
• tetracyclines (30 days)
• aspecific immunoglobulins (1 year)
• infectious diseases
• HHV-4 / EBV (1 year)
• rubella virus (3 months)
• HHV-3 / VZV (3 months)
• influenzavirus (7 days)
• Toxoplasma gondii (1 year)
• Brucella melitensis (2 years)
• Rickettsia spp. (1 year)
• major surgery (1 year)
• minor surgery (3 months)
• tattoos (6 months)
• earlobe hole (6 months)
• occasional sexual intercourse (1 year)
• acupuncture (6 months)
• transfusion (5 years)
• permanent exclusion
• drug or alcohol addiction
• epilepsy
• severe diabetes mellitus
• severe systemic arterial hypertension or treatment with b-blockers
• autoimmune diseases
• diffuse dermatoses
• severe rheumatic diseases
• acting or previous hepatitis B or hepatitis C
• neoplasms
• cardiovascular diseases
• severe hematological diseases
• chronic nephropathies
• mental instability
• severe dysendocriniae
Transfusion : the introduction of whole blood or blood components directly into the bloodstream
• exchange, exsanguination, replacement or substitution transfusion / exsanguinotransfusion : repetitive withdrawal of small amounts of blood and replacement with donor blood, until a large proportion of the blood volume has been exchanged; used primarily in newborn infants with erythroblastosis fetalis and sometimes in patients with various other blood conditions
• fetomaternal transfusion : transplacental passage of fetal blood into the circulation of the mother; in small amounts it may go unnoticed, but in larger amounts it can cause anemia or edema in the fetus.
• direct or immediate transfusion : the transfer of blood from one person to another without use of an intermediate container or anticoagulant
• mediate or indirect transfusion : transfer of blood from a donor to a flask or other container, and then to the recipient
• intraperitoneal transfusion : infusion of blood into the peritoneal cavity
• intrauterine transfusion : transfusion performed on an unborn infant in utero, often referring to transfusion of Rh-negative blood into the infant's peritoneal cavity in the treatment of erythroblastosis fetalis in utero
• autotransfusion / autologous transfusion : reinfusion of blood or blood products derived from the patient's own circulation; contraindicated in neoplastic patients due to risk of spreading neoplastic emboli.
• intraoperative autotransfusion : the collection, processing, and reinfusion of a patient's blood shed from a wound or body cavity during surgery.
• postoperative autotransfusion : the collection, processing, and reinfusion of the patient's blood shed from the mediastinum following open heart or chest surgery or from the chest following traumatic hemothorax
Transfused components :
• whole blood :

Donation of 1 unit (450 ml +/- 10%) of whole blood causes a reduction of 1 g/dl of hemoglobin in the donor after 24 hrs.
WBC residue : 2-5 x 10⁹ WBC/unit
Storage : reduction of RBC 2,3-BPG and ATP content, increase of extracellular potassium and reduction in pH. Coagulation factors V, VIII, and XI reduce by 80-90% after 2 weeks. At +4 +/-2 °C... :
• up to 21 days in citrate-phosphate-dextrose (CPD)
• up to 35 days in citrate-phosphate-dextrose-adenine (CPDA)
Transfusion should ensure persistence of > 70% of transfused RBCs after 24 hrs; 2,3-BPG and ATP storages are regenerated within 24 hours.
Pretransfusional investigations : whole blood : blood group, irregular (not constant) anti-RBC Ab and E/S crossmatch test
immediate-spin (IS) crossmatch
An ABO-incompatible red blood cell (RBC) transfusion (i.e., transfusion of RBCs with A or B antigens to a recipient with the corresponding antibodies) is fatal in 10% of cases and is the main cause of death from transfusion. Errors leading to an ABO-incompatible transfusion can occur at any point in specimen collection, testing and patient identification. Fastidious adherence to proper patient identification and labelling procedures is required of all people involved in the transfusion process.
Type and screen : when a sample of a recipient's blood and requisition form arrive at the blood bank, they are checked against each other to ensure that the information is consistent and complete, as required by the standards for pretransfusion testing established by the American Association of Blood Banks, local hospital policy and national standards. If there is any discrepancy or if information is missing, the specimen will be rejected and the ward notified that a recollection is necessary. Even the most seemingly minor labelling error can be associated with an extremely high risk of recipient misidentification, hence these specimens are discarded.

procedure	estimated turnaround time, min (time from receipt of an acceptable specimen and requisition form at the blood bank to issuance of RBCs or completion of test. Turnaround times will vary between institutions)	risk of acute hemolysis, % (the estimated probability that the recipient will experience an overt acute hemolytic reaction if RBCs are administered after the procedure is completed. Overall, about 5% of recipients will have an unexpected antibody; the risk of an acue hemolytic reaction is diminished only when antibody screening methods are performed)
emergency issue of uncrossmatched RBCs	5	5
AB0 and RhD type only	15	5
type and screen	45	< 0.1
type and screen + computer crossmatch (this procedure can be performed when no unexpected antibodies are identified. The time listed represents the fastest time that crossmatched blood can be provided to a ward	60	< 0.1
type and screen + serological crossmatch (antibody identification can take several hours depending on the nature of the antibody. Locating rare RBC units that lack a high-incidence antigen, or combination of antigens, can take days and may require consultation of a rare-donor registry or the use of frozen RBCs)	> 120	< 0.1

If the specimen is acceptable for pretransfusion testing, the first step in ensuring serologic compatibility between the donor and recipient is to perform a type and screen, which takes about 45 minutes. It consists of 2 distinct tests. The "type" (or "group") test determines which ABO antigens are present on the the patient's RBCs. It also usually features a test for the RhD antigen. The type test is divided into 2 steps. The first step uses commercially available antibodies that will react with either the A or B antigens, if present, on the patient's RBCs and cause them to agglutinate. This is known as forward (cell) typing. RBCs from a person with type AB blood will react with both anti-A and anti-B antibodies, whereas those from a person with type O blood will not react with either antibody. The RhD antigen is tested in the same manner, with commercially available anti-D antibodies mixed with the RBCs (Box 1). The second step of the type test uses commercially available A1 and B cells that will react with antibodies, if present, in the recipient's plasma. This is called reverse (serum) typing. Almost everyone has naturally occurring antibodies to the ABO antigens they lack — a person with type O blood will have both anti-A and anti-B antibodies in their plasma, whereas a person with type AB blood will have neither of these antibodies in their plasma. These forward and reverse typing tests are used together to establish a patient's ABO type.
The "screen" test is done to determine whether the recipient has formed what are known as "unexpected" or "irregular" RBC antibodies. About 3–10% of recipients who have received multiple RBC transfusions will have antibodies to non-ABO antigens^{ref1, ref2}. This is in contrast to the regular, predictable occurrence of antibodies to the ABO antigens that the recipient lacks; hence the moniker "unexpected". The screen is performed by using 2 or 3 commercially available type O cells that, between them, express essentially all of the approximately 20 clinically significant RBC antigens. By incubating the recipient's plasma with these cells and looking for agglutination of the RBCs or hemolysis caused by antigen-antibody interactions, unexpected antibodies can be detected and the identification process begun. If unexpected antibodies are found, additional testing, sometimes taking several hours, is required to identify them and to locate antigen-negative RBC units for transfusion.  A type and screen is valid for up to 3 days if the recipient has received a transfusion or has been pregnant in the past 3 months. A pregnant woman can form antibodies to foreign antigens (i.e., paternally derived) on fetal cells should a feto-maternal hemorrhage occur; thus, it is important to repeat the type and screen if a woman requires a transfusion within 3 months of delivery. No standard exists for how long a type and screen is valid in patients who have not been transfused or pregnant in the preceding 3 months; for an exact duration, consult your local blood bank.
Crossmatch (XM) : a crossmatch is performed to ensure compatibility between the donor's RBCs and the recipient's plasma. It can be done serologically to ensure compatibility with both anti-ABO and non-ABO antibodies or by computer as a check on ABO compatibility. If the recipient has a negative antibody screen (has not formed unexpected antibodies), the computer can be used to electronically match the ABO type of the recipient with a compatible donor unit using laser wands and bar-code technology. The computer system must have the logic to recognize and allow an RBC unit to be issued if the ABO match between a donor and a recipient is compatible and to reject units that are incompatible. In the absence of computer crossmatch technology, a serologic crossmatch is required to ensure ABO compatibility. Steps in italics represent the main time-consuming procedures in pretransfusion testing. *If a computer crossmatch system is unavailable, a second verification of ABO compatibility between donor RBCs and recipient plasma is required

In the absence of a computer crossmatch system, a second verification of ABO compatibility must occur before a unit of RBCs can be issued. If no unexpected antibodies are detected after the type and screen tests, an ABO-compatible RBC unit is selected and mixed with the recipient's plasma. This mixture is briefly centrifuged and inspected for hemolysis and agglutination; if both are absent, ABO compatibility is verified and the RBC unit issued. This procedure must be repeated for each donor RBC unit. If unexpected antibodies are detected in the recipient's plasma, a similar procedure is used to verify ABO compatibility, but the donor RBC units are selected to be compatible with the recipient's antibody. *This step represents the first verification of ABO compatibility.

If a recipient has formed an unexpected antibody, the blood bank cannot use the computer crossmatch system. Instead, a serologic crossmatch is required. It involves mixing the recipient's plasma with a potential donor RBC unit (selected by immunologic testing to be antigen negative) and inspecting for agglutination or hemolysis to ensure that the RBC unit truly lacks the antigen corresponding to the patient's antibody. Uncrossmatched RBC units are always type O (universal donor) and often RhD negative, thus they can be safely transfused to virtually any recipient in an emergency situation when the typically short delay caused by pretransfusion testing to find ABO-matched units would compromise the patient's life. The XM has been modified many times and, in recent years, has been abbreviated. The 2 common types of XM currently being done are
• immediate spin XM for antibody-negative patients
• antiglobulin XM for the rest is generally considered optional, unless a clinically significant antibody is present
Originally, the XM was intended to be a final check for ABO compatibility and for the detection of unexpected antibodies. Electronic XM (EXM) was first introduced at the University of Michigan Medical Center in 1992 and is in use in at least 10 North American facilities, Scandinavia, Hong Kong and Australia. Some provide blood at remote sites lacking laboratory services.
Indications : acute hypovolemia (> 50% of blood mass lost in < 3 hours), neonatal exsanguinotransfusion (requires blood not older than 7 days; in HDN due to AB0 incompatibility, use mother- and newborn-compatible AB0 whole blood suspended in newborn-compatible plasma)
• packed RBCs (PRBC)

WBC residue : 2-5 x 10⁹ WBC/unit
Storage : at +4 +/-2 °C... :
• if HCT < 80% : up to 35 days in citrate-phosphate-dextrose-adenine (CPDA)
• if HCT > 80% : saline adenine glucose mannitol (SAGM), PAGS, or glycerol (10 years)
• low-glycerol method (LGM) (20%)  : freezed at -80°C, then kept at -65°C
• high-glycerol method (HGM) (40%) : more pronounced hemolysis, freezed in liquid nitrogen (-196°C), then kept at -120°C
Stability after washing during cold storage in SAGM, as measured by hemolysis, is better for HGM cells as compared to LGM cells^ref.
Compatibility :

recipient group	RBC antigen	plasma Ab	compatible RBCs	compatible plasma
0	-	anti-A and anti-B	0	0, A, B, AB
A	A	anti-B	A, 0	A, AB
B	B	anti-A	B, 0	B, AB
AB	A and B	-	AB, A, B, 0	AB
Rh(D)+	D	-	Rh(D)+, Rh(D)-	-
Rh(D)-	-	anti-D (immunized patients)	Rh(D)-	-

Indications : anemia (< 8 g/dl) unresponsive to drugs, chronic anemia < 7 g/dl, newborn anemia < 13 g/dl in the first day of extrauterine life or < 10 g/dl in following days.
Dose to transfuse [ml] = weight [kg] x 70 x (desired HGB increase) [g/dl] / (HGB in the blood unit [g/dl])
Do not transfuse more than 1-2 units per time, monitoring increase in HGB after 30 minutes-24 hours since end of transfusion in medical patients and after 48-72 hours in surgical patients. Usually 1 unit of PRBC should increase HGB by 1 g/dl.
• leukodepleted or leukocyte-reduced RBC units :

WBC residue after ... :
• removal of buffy coat : < 1.2 x 10⁹ WBC/unit
• filtration :
• post-storage filtration :
• bedside filtration. Side effects : posttransfusion hypotension with polyesther filters
• laboratory filtration
• pre-storage filtration < 5 x 10⁴
Indications :
• < 10⁸ WBC/unit : prophylaxis of nonhemolytic febrile transfusion reactions
• < 5 x 10⁶ WBC/unit :
• prevent GvHD
• prevent immunodepression
• prevent anti-leukocyte antigen immunization
• prevent transmission of CMV, EBV, HIV-1/2 and HTLV-I/II and/or reactivation of HIV-1, PrPSc (pre-storage filtration in UK)
• intrauterine transfusion (also irradiated)
Filtration produced a mean reduction in total WBCs of 3.2 log. New-generation RBC filters reduce WBC concentrations by 4 to 5 logs^ref. Monocytes, lymphocytes, and neutrophils were reduced by 4.1, 3.8, and 2.5 log, respectively. Lymphocyte subsets also demonstrated differential reduction with filtration. All WBC subsets showed ongoing loss during storage^ref. Universal leukocyte reduction (ULR) is being considered as a new standard, few data are available on the performance of WBC-reduction filtration in routine practice. The current FDA requirement for WBC-reduction in RBCs (<5 x 10⁶), the proposed FDA requirement (<1 x 10⁶), while a more stringent proposal (<5 x 10⁵) for residual WBCs per RBC unit. Among the WBC-reduced RBC units, 0.8% exceed 5 x 10⁶ WBCs per unit, 8.3% exceed 1 x 10⁶ WBCs per unit, and 14.3% exceeded 5 x 10⁵ WBCs per unit^ref.
• washed RBC : in NS at +4°C, until protein residue < 0.5 g/unit.

Storage : < 24 hours at +4 +/-2 °C
Indications : prevention of allergic reactions to plasma proteins (e.g. IgA deficiency, who should receive only blood components from other patients), neonatal transfusion (to reduce anticoagulant administration)
• irradiated RBCs : 2500 rad (25 Gy) of g-rays

Storage : < 28 days (loss of potassium), < 48 hours for intrauterine or neonatal transfusions (also leukodepleted)
Indications : prophylaxis of transfusion-associated GvHD
• platelets :

Source : the donor should have discontinued ASA in the last 72 hours
• platelet-rich plasma of a single unit (> 0.6 x 10¹¹ PLT/unit)
• pool of 4-8 buffy coats (> 2.5 x 10¹¹ PLT/unit)
• apheresis platelets :
• single-component blood donation : > 3.0 x 10¹¹ PLT/unit
• multi-component blood donation : > 2.0 x 10¹¹ PLT/unit
Storage :
• continued agitation at +22 +/-2 2 °C :
• closed system : 5 days
• open system : 24 hours
• cryopreserved with DMSO =>
• in gaseous phase of liquid nitrogen (-120°C) for 10 years
• in mechanical freezer (-65°C) for 1 year
Indications :
• autoimmune thrombocytopenia before treatment with antiblastic drugs
• autologous HSCT recipients
• rare phenotypes
• maternal platelets for newborns with maternal-fetal alloimmune thrombocytopenia
WBC residue :
• fractionation of whole blood : < 0.2 or < 0.05 x 10⁹ WBC/unit
• apheresis platelets : < 1 x 10⁹ WBC/unit
• leukodepleted platelet concentrates :
• apheresis platelets with leucoreduction system (LRS) : < 5 x 10⁴ WBC/unit
• filtration : < 5 x 10⁶ WBC/unit
Irradiated platelet concentrates : 25 Gy of g-rays
Washed platelet concentrates
Pretransfusional investigations : blood group, P/S cross-match and/or HLA typing (immunological refractariness), E/S compatibility crossmatch (if RBC residue > 2 ml). ABO compatibility for platelet transfusion is desirable but not required because of the small amount of plasma present in a standard dose of platelets (each unit contains about 60 mL of plasma, and 5 or 6 units make up a standard dose). However, platelets have a short shelf life (5 days) and ABO-matched pools may not be available for the recipient; therefore, most institutions will cross ABO boundaries when issuing platelets (e.g., issuing type A platelets to a type B recipient). Typically the only adverse event of crossing ABO lines is that the recipient may have a positive direct antiglobulin test result, but significant hemolysis is very rare. It is important to remember that platelets themselves have ABO antigens on their surface, and thus a donor– recipient ABO mismatch may result in poor recovery of platelets after transfusion.

recipient's AB0 type	compatible plasma	compatible RBCs	compatible platelets
			first choice	second choice
A	A, AB	A, 0	A, AB	B, 0
B	B, AB	B, 0	B, AB	A, 0
0	0, A, B, AB	0	0 (although type 0 RBCs do not have A or B antigens, the recipient's plasma contains anti-A and anti-B antibodies, which could reduce the recovery of transfused platelets bearing A or B antigens)	A, B, AB
AB	AB	0, A, B, AB	AB	A, B, 0

Even if platelets do not express Rh(D) antigen, do not trasnfuse platelets from Rh(D)⁺ donors to fertile female because residue RBC could induce alloimmunization; alternatively administer anti-D :
• 10 mg /tranfused platelet unit derived from whole blood containing < 0.5 ml RBCs
• 50-100 mg/transfused platelet unit derived from apheresis according to hematocrit and volume (20 mg anti-D neutralizes 1 ml Rh(D)⁺ RBCs)
In immunological refractoriness to platelet transfusion,
• cross-match according to HLA and AB0 antigens
• pretreatment with citrate removed HLA-I Ag
Indications :
• prophylaxis when PLT < 5,000-10,000/ml (< 10,000/ml if fever, infections, minor hemorrhage, < 20,000/ml if coagulopathy, heparin, antiblastic chemotherapy, amphotericin B). The 20,000/ml trigger^ref. The 10,000/ml transfusion trigger is associated with significantly greater exposure to low PLT counts. Nonbleeding patients with profound thrombocytopenia were at significantly greater risk of dying compared with nonthrombocytopenic patients^ref. A prophylactic PLT transfusion trigger level of less than 10 x 10(9) PLTs per L instead of less than 30 x 10(9) PLTs per L in allogeneic HPC transplant recipients was found to be safe and resulted in a decreased use of PLTs^ref. A slight reduction in PLT transfusions per patient in 10,000/ml compared with 20,000/ml was not statistically significant (odds ratio, 0.82; 95% confidence interval, 0.51-1.33; p = 0.416), yet a significantly higher proportion of patients in 10,000/ml had PLT counts less than or equal to 10,000/ml compared to 20,000/ml (p < 0.001). In patients who bled, however, there was no excess exposure to low PLT counts before bleeding started. A substantial number of patients who bled received PLT transfusions above the goal before bleeding started (82.9% in 10,000/ml, 41.5% in 20,000/ml) because of medical complications that associated with increased risk of bleeding. Bleeding incidence was similar in both study periods (21.9% in 20,000/ml, 16.4% in 10,000/ml; p = 0.526). Bleeding was significantly associated with reduced survival in both study periods^ref.
• therapy of active bleeding  if < 50,000/ml ore more if critical site (intracranial hemorrhage)
• acquired platelet functional defects (e.g., due to medications, or after cardiac bypass surgery)
Dose [units of whole-blood derived platelet concentrate] = (desired platelet increase/ml) x BSA / 10,000
1 apheresis-derived platelet concentrate unit equals to 5 whole-blood derived platelet concentrate units. Dose should be doubled in babies, fever, sepsis, splenomegaly.
Since 40% of infused platelets are immediately removed from circulation (splenic sequestration, adhesion to endothelium), transfusion of 3.2 x 10¹¹ PLT (4-5 whole-blood derived concentrates or 1 apheresis-derived concentrate) increases by 20,000/ml the platelet count for 24-72 hours. Correct count increment (CCI) after 1-2 and 18-24 hours since end of transfusion = (observed increment) x BSA x 10¹¹ / (number of transfused platelets) should be :
• > 7,500/ml after 1 hour
• > 5,000/ml after 18-24 hours
CCI < 7,500/ml after 1 hour suggest immunological refractoriness
CCI > 7,500/ml after 1 hour but < 5,000/ml after 18-24 hours suggest reduced survival due to nonimmunological factors (sepsis, fever, hepatosplenomegaly, DIC, DM, cardiac valve prosthesis, vasculitis, amphotericin B)
• leukocyte-reduced platelet units : prestorage WBC filtration of platelet concentrates is superior in reducing the absolute numbers of WBC. However, both pre- and poststorage WBC filtration significantly affect the proportions of WBC in the final product, decreasing the number of T cells while apparently increasing the proportion of MHC class II⁺ cell populations^ref.
• neutrophils : 1 U contains 10¹⁰ granulocytes.
• transfusion-associated GvHD can be prevented by irradiation
Storage : < 12 hours at +22 +/- 2°C without agitation. Collection may be increased :
• adding RBC-sedimentating agents such as HES, LWMD, gelatin, ...
• s.c. recombinant G-CSF use has increased the granulocyte yield by approximately 4-fold^{ref1, ref2, ref3}
• G-CSF + oral dexamethasone^{ref1, ref2}
Indications : multiple recent studies have shown that granulocyte transfusions can be helpful in controlling severe infections progressing despite the use of appropriate antibiotics, with a response rate of 40-80% with variability in results depending on patient characteristics. This benefit is limited to a small patient population as the incidence of prolonged reversible neutropenia is relatively small. Severe side effects have been rare in those studies.
• chronic granulomatous disease
• severe neutropenia (< 500/ml) with febrile bacterial infections (expecially Gram-negative septicemia) resistant to antibacterial therapy for 2-3 days, when life expectancy is reasonable and restart of granulopoiesis is expected after 1 week and before 2-3 weeks
• adult oncology patients and progenitor cell transplant recipients, in whom neutropenia complicated by severe infections persists as a significant problem, despite combination antibiotic therapy, recombinant cytokines, myeloid growth factors, and use of mobilized peripheral blood progenitor cells
Pretransfusional investigations : blood group (AB0 compatibility and cross-match if RBC > 2 ml/unit), ANCA (2-3 times a week during therapy), anti-HLA usually considered not relevant but actually it is. Nonalloimmunized patients can receive cells from nonmatched ABO compatible donors, while alloimmunized patients should receive granulocytes from either HLA-matched donors or donors selected by leukoagglutination or lymphocytotoxicity crossmatching^refcomponents from CMV-seropositive AlloPBSC donors
Dose : > 2 x 10¹⁰ granulocytes/m² in 2 administrations.
Transfusion of 1 granulocyte concentrate in a 70-kg patient induces an increase of ANC of only 200/ml. Leukocyte incompatibility adversely affected ANC increments after the transfusion of G-CSF-mobilized granulocyte components and clinical outcomes after PBSC transplantation. Beginning on transplant day 2, 23 evaluable recipients were scheduled to receive 4 alternate-day transsuggest that future efficacy trials should consider inclusion of unrelated community donors for timely institution of granulocyte transfusion therapy.
fusions of granulocyte components apheresed from a single donor given G-CSF. G-CSF was also given to recipients after transplantation. Recipient ANC was determined before and sequentially after each granulocyte transfusion to determine the peak ANC increment. Leukocyte compatibility was determined at study entry only by a lymphocytotoxicity screening assay (s-LCA) against a panel of HLA-defined cells. 8 recipients had positive s-LCA. On days 2 and 4, the mean peak ANC increments after granulocyte transfusion were comparable between the cohorts with positive and negative s-LCA. However, the mean peak ANC increments on day 6 (246/ml vs 724/ml; P =.05) and day 8 (283/ml vs 1079/ml; P =.06) were lower in the cohort with positive s-LCA, in spite of the transfusion of comparable component cell doses. Adverse reactions occurred with only 5 of 87 (5.7%) granulocyte transfusions and were not associated with leukocyte compatibility test results. Platelet increments, determined 1 hour after granulocyte transfusion, were comparable between the cohorts. Although the 2 cohorts received PBSC components with similar CD34⁺ cell doses, the cohort with a positive s-LCA had delayed neutrophil engraftment and a greater number of febrile days and required more days of intravenous antibiotics and platelet transfusions^ref. Anyway another study showed that the ANC increment after the first, second, and seventh transfusions in patients who had community donors was significantly higher or comparable to patients who had family donors, suggesting that future efficacy trials should consider inclusion of unrelated community donors for timely institution of granulocyte transfusion therapy^ref. There is a modest, but significant, benefit of G-CSF-mobilized HLA-matched prophylactic granulocyte transfusions in neutropenic allogeneic PBPC recipients^ref.
Side effects : as above + cough, fever, dyspnea, polypnea, respiratory failure in patients treated with amphotericin B. In an era of effective surveillance and preemptive therapy for CMV, AlloPBSC recipients can safely receive 2 transfusions of prophylactic G-CSF-mobilized granulocytes^ref
• natural killer (NK) cells : purification of human NK cells from leukopheresis products using a clinical-scale 2-step immunomagnetic method :
• CD3⁺ cells are first depleted and then CD56⁺ cells are enriched from the CD3⁺ cell-depleted products. The median percentage of CD3^-CD56⁺ NK cells in the final products is 91.0%, and the median recovery was 48.7%. The median depletion for CD3⁺CD56^- T cells was 5.3 log. Natural cytotoxicity of the purified cells us approximately 5-fold higher than that of unpurified mononuclear cells, and it could be further increased by stimulation of the purified cell with IL-2^ref
Complications :
• immediate reactions :
• immunological reactions :
• febrile nonhemolytic transfusion reaction (FNHTR) (1–4:100)

Prevention : leukodepleted blood derivatives; antipyretics before transfusion
Therapy : antipyretics
• allergic reaction (1–4:100)
• urticaria :

Prophylaxis : washed blood derivatives; antihistamines administered before transfusion
Therapy : i.v. antihistamines (chlorpheniramine 10 mg); after 30 min transfusion can be restarted slowly
• anaphylactic reaction (1:150,000)

Prophylaxis : washed blood derivatives; donor's blood derivatives with the same defect in IgA deficiency recipients
Therapy : adrenaline 0.4 ml s.c. OR 0.1 ml diluted in 10 ml NS i.v. in 5' in severe shock; glucocorticoids
• transfusion-related acute lung injury (TRALI) (1:5,000)
• noncardiogenic acute pulmonary edema, acute renal failure

Therapy : i.v. glucocorticoids, respiratory support
Prophylaxis : anti-WBC Ab-free plasma
• acute hemolytic reaction (1:12,000) : alloantibodies against recipient's RBCs found in donor's plasma or alloantibodies against donor's RBCs found in recipient's plasma
• fatal hemolytic reaction (1:100,000)
Therapy : prevent acute renal failure with i.v. fluids (NS 1000 ml in 1-2 hrs or 100 ml 20% mannitol in 5') and diuretics (furosemide 20-80 mg i.v. or ethacrinic acid 50-100 mg i.v.) to maintain diuresis > 100 ml/min, avoiding hyperhydration. Correct hypotension with dopamine 5 mg/kg/min. Treatment of DIC with FFP and eventually heparin (usually recommended in transfusions > 200 ml AB0-incompatible blood). Treatment of renal failure with hemodialysis
• platelet transfusion refractoriness : alloantibodies against HLA and/or anti-HPA in recipient's plasma
• passive alloimmune thrombocytopenia : alloantibodies against HPA in donor's plasma
• nonimmunological reactions :
• circulatory overload

Prophylaxis : low infusion rate (1 ml/kg/hr), concentrated blood derivatives, diuretics before transfusion
Therapy : diuretics (furosemide 40 mg i.v.), oxygen therapy, Digitalis glucosides
• bacterial contamination reaction :

Prophylaxis : controlled sampling, preparation and stocking, accurate visual inspection of blood derivatives before transfusion
Therapy : steroids, antibiotics, vasopressors, plasma expanders, therapy for DIC, move to ICU
• nonimmunological hemolysis

Prophylaxis : adequate preservation of RBC; no additives, accurate visual inspection of the unit before transfusion
Therapy : fluids, correct hypotension, renal function monitoring, dialysis in severe cases
• delayed complications :
• immunological reactions :
• delayed hemolytic reaction (1:1,000) : alloantibodies against RBCs of the donor produced by secondary immune response in the recipient
• transplant-associated hemolytic reactions : aloantibodies against recipient's RBC produced by immunocompetent cells of the donor
• transplant-associated alloimmune thrombocytopenia : alloantibodies against HPA antigens of the recipient produced by immunocompetent cells of the donor; OR alloantibodies against HPA antigens of the donor produced by immunocompetent cells of the recipient
• bystander immune haemolysis (BIH) : adsorption of alloantigens of Ag-Ab complexes on recipient's RBCs. Cross-reactive alloantibodies
• post-transfusion purpura
• post transfusion graft-versus-host disease (PT-GVHD) / transfusion associated graft versus host disease (TA-GVHD) (rare) : a serious complication of blood transfusion with a high mortality rate. It occurs when immunologically competent lymphocytes from the donor are introduced into an immunoincompetent host who is unable to destroy the donor lymphocytes. The donor lymphocytes engraft, recognize the host as foreign and then attack host tissues. GVHD occurs most commonly after allogenic HSCT and less often after transfusion of non-irradiated cellular blood components especially when the blood donor and recipient share similar HLA antigens^ref. In this case, the recipient does not recognize the transfused donor cells as foreign and cannot reject them. The transfused viable T-cells react against the second haplotype on HLA that are not shared, with the resulting clinical picture of TA-GVHD^ref. Involvement is multi-systemic and patients usually present with high grade fever, a maculopapular erythematous scaly rash, hepatocellular damage with elevated hepatic enzymes, profuse and acute onset diarrhea and hematological manifestation in the form of pancytopenia and its resulting complications^ref. Histological changes are non-specific and primarily affect the skin, liver and the gastro-intestinal tract^ref. Characteristic changes in the skin include epidermal basal cell vacuolation; mononuclear cell infiltration in the epidermis and degeneration of the epidermal basal layer. Bulla formation and ulceration of the skin may also be seen. The liver may show degeneration of the small bile ducts and periportal mononuclear infiltrates associated with hepatocellular and cholangiolar cholestasis. The bone marrow may be hypocellular or aplastic with a lymphocytic or histiocytic infiltration along with haemophagocytosis^ref. Other predisposing factors of GVHD are congenital or acquired immunodeficiency, young age and transfusion with fresh whole blood^{ref1, ref2}. Multi-systemic involvement (bicytopenia, maculopapular erythematous rash, fever, watery diarrhea and jaundice following the blood transfusions with related donor) and the high mortality rate associated with this condition necessitates that pediatricians should be aware of this largely preventable condition^{ref1, ref2}. Clinical signs and symptoms in the initial phase can be confused with a variety of other conditions like Stevens Johnson syndrome, viral infections, drug reactions & reactive and familial erythrophagocytic syndromes. Hence a high index of clinical suspicion and relevant pathological support is required for its diagnosis. TA-GVHD has been reported from India in 3 full term neonates, all of whom died^{ref1, ref2}. Corticosteroids, antithymocyte globulin, cyclosporine and/or growth factors have been recommended for treatment either singly or in various combinations. However, attempts at treatment of TA-GVHD are largely ineffective. Newer modalities that have been tried include nafmostat mesilate, chloroquin and daclizumab. Irradiation of blood products prior to transfusion has reduced if not eradicated transfusion- related GVHD^{ref1, ref2}. Other methods under investigation include photoinactivation with the use of psoralen S59 with UV-A light, or the use of photoactive phenothiazine dyes^ref. The rapid downhill course, poor response to therapy and high mortality associated with transfusion associated graft versus host disease make its prevention a priority. Therefore optimizing blood/component use, reducing inappropriate transfusions and more importantly avoiding the use of related donors for transfusions is a more realistic option of preventing transfusion associated graft-versus-host disease in clinical practice.
• immunomodulation
• alloimmunization :
• RBC allosensitization (1:100)
• HLA allosensitization (1:10)
• nonimmunological :
• iron overload / hemochromatosis
• transfusion-associated transmission (TAT) of hematogenous infections
• HBV (1:63,000)
• HCV (1:1,600,000)
• HIV-1 (1:1,960,000)
• HIV-2 (none reported)
• HTLV-I and -II (1:641,000)
• malaria (1:4,000,000)
• infectious agents rarely associated with transfusion, theoretically possible or of unknown risk include: HAV, parvovirus B-19, Babesia microti (babesiosis), Borrelia burgdorferi (Lyme disease), Trypanosoma cruzi (Chagas disease), and Treponema pallidum subsp.pallidum, HHV-8 and HGV.
Risk prevention : some 60% of global blood supplies go to 18% of the world's people, leaving 82% of the global population inadequately covered. So far, only 40 countries have established a 100% voluntary blood donation system, and < 30% of countries have a nationally coordinated blood transfusion service in place. HIV-contaminated blood still accounts for approximately 5% of HIV infections in Africa. While in many countries more and more testing is being done to make blood safe, the WHO said most developing nations do not test for diseases such as HIV-1 or HBV and HCV. Annually, some 6 million tests that should be done for infections are not done
• presumptive viremic blood donors (PVDs)
• testing of blood donors for HIV-1 and HCV RNA by means of nucleic acid amplification was introduced in the USA as an investigational screening test in mid-1999 to identify donations made during the window period before seroconversion : minipool nucleic acid–amplification testing has helped prevent the transmission of approximately 5 HIV-1 infections and 56 HCV infections annually and has reduced the residual risk of transfusion-transmitted HIV-1 and HCV to approximately 1 in 2 million blood units^ref. The prevalence rates of HBV, HCV, HIV-1, and HTLV infections are lower among tissue donors than in the general population. The prevalence of confirmed positive tests among tissue donors was 0.093% for anti-HIV, 0.229% for HBsAg, 1.091% for anti-HCV, and 0.068% for anti-HTLV. The incidence rates were estimated to be 30.118, 18.325, 12.380, and 5.586 per 100,000 person-years, respectively. The estima