BCTXP key terms

The highly polymorphic cell-surface proteins that present peptides to T cells and define tissue identity; matching donor and recipient HLA reduces alloimmune recognition of a transplanted organ.

The percentage of a reference donor population against which a candidate's serum reacts, estimating how broadly sensitized the patient is and how hard compatible organs will be to find.

A sensitization metric computed from the candidate's unacceptable HLA antigens weighted by their frequency in the donor pool, replacing older cell-based PRA testing with a more reproducible estimate.

A compatibility test between donor cells and recipient serum; a positive result signals preformed donor-specific antibody and predicts hyperacute or early antibody-mediated rejection.

Predicting physical crossmatch results by comparing the donor's HLA typing against the recipient's listed unacceptable antigens and antibody profile, allowing organ offers without waiting for a wet crossmatch.

Antibodies directed against a particular donor's HLA antigens, whether preformed before transplant or formed afterward; their presence and strength guide rejection risk assessment and treatment decisions.

The state of having broad anti-HLA antibodies from prior pregnancy, transfusion, transplant, or infection, which narrows acceptable donors and lengthens waiting time on the match run.

Immediate graft destruction within minutes to hours caused by preformed antibody activating complement and thrombosing the graft vasculature; it is now rare because of pretransplant crossmatching.

T-cell-mediated injury of the allograft, typically occurring days to months after transplant, marked by interstitial inflammation and tubulitis in kidney grafts and responsive to corticosteroid pulses.

Graft injury driven by donor-specific antibody with complement activation or endothelial injury, diagnosed using microvascular inflammation, C4d staining, and circulating antibody evidence.

An international consensus scheme that standardizes the histologic diagnosis and grading of allograft rejection and other graft pathology, enabling comparable reporting across centers and trials.

A crossmatch method in which donor lymphocytes are incubated with recipient serum and complement; cell lysis indicates complement-fixing donor-specific antibody and contraindicates transplant.

A more sensitive crossmatch technique using fluorescently labeled antibodies and flow analysis to detect low-level donor-specific antibody that a standard cytotoxicity assay could miss.

Pretransplant strategies such as plasmapheresis, intravenous immunoglobulin, or complement inhibition that lower antibody levels so a highly sensitized candidate can accept an otherwise incompatible organ.

A laboratory-based severity score using bilirubin, creatinine, and INR that ranks liver transplant candidates by short-term mortality risk and allocates deceased-donor livers accordingly.

A standardized or approved MELD adjustment granted to candidates whose mortality risk is underestimated by laboratory values, such as those with hepatocellular carcinoma or cholangitis.

The registry of candidates actively seeking an organ, ordered by urgency and compatibility rules so that offers are made to the most appropriate recipient when a donor becomes available.

A structured pretransplant assessment of mental health, substance use, social support, and adherence capacity that identifies risks and targets interventions before listing.

The federally designated agency responsible for identifying potential deceased donors, obtaining authorization, managing donors, and recovering organs within its service area.

Organ recovery from a donor declared dead by neurologic criteria while circulation is maintained on mechanical support, historically the most common source of deceased-donor organs.

Recovery of organs after withdrawal of life-sustaining treatment and circulatory arrest, requiring rapid procurement and carrying higher risks of ischemic injury, especially for livers and hearts.

The clinical protocol confirming irreversible loss of all brain function, including coma, absent brainstem reflexes, and apnea testing, with prerequisites and confounders excluded before declaration.

The interval between cold preservation flush of a recovered organ and its reperfusion in the recipient; longer times increase preservation injury and delayed graft function risk.

Preservation by flushing the organ with cold electrolyte solution and keeping it on ice, which slows metabolism but provides no active assessment or oxygen delivery.

Continuous pumping of cold or normothermic oxygenated perfusate through a recovered organ, allowing metabolic support and viability assessment while extending acceptable preservation intervals.

The need for dialysis within the first week after kidney transplant, usually reflecting ischemia-reperfusion injury; it complicates management and is associated with worse long-term graft survival.

Cellular damage caused by oxygen deprivation during preservation followed by the inflammatory burst on reperfusion, contributing to delayed function and increased immunogenicity of the graft.

Intensive immunosuppression given around the time of transplant, often lymphocyte-depleting or IL-2 receptor-blocking antibodies, to prevent early rejection while maintenance drugs reach steady state.

The long-term drug regimen, typically a calcineurin inhibitor plus an antimetabolite and corticosteroid, that sustains tolerance of the graft while limiting cumulative toxicity.

A calcineurin inhibitor and cornerstone of most maintenance regimens; it has a narrow therapeutic index requiring trough monitoring and causes nephrotoxicity, neurotoxicity, and glucose intolerance.

An antimetabolite that blocks lymphocyte proliferation by inhibiting inosine monophosphate dehydrogenase; it is teratogenic and commonly causes gastrointestinal upset and leukopenia.

Serial measurement of blood drug concentrations, usually calcineurin inhibitor troughs, to keep levels within a target range that balances rejection prevention against toxicity.

Failure to take immunosuppression or attend follow-up as prescribed; it is a leading modifiable cause of late rejection, donor-specific antibody formation, and graft loss.

A herpesvirus that reactivates or is transmitted with the graft under immunosuppression, causing fever, myelosuppression, colitis, and pneumonitis; prevention relies on prophylaxis or preemptive monitoring.

A virus that reactivates in immunosuppressed kidney recipients and causes polyomavirus-associated nephropathy with tubulointerstitial inflammation, often requiring reduction of immunosuppression rather than antiviral therapy.

A spectrum of lymphoid proliferations arising after transplant, usually Epstein-Barr virus-driven and linked to intensified immunosuppression; treatment centers on reducing immunosuppression and rituximab-based therapy.

Donor immune cells attacking recipient tissues, most familiar after hematopoietic stem cell transplant but also a rare complication of organs rich in lymphoid tissue such as the intestine.

The rules governing how deceased-donor organs are distributed among candidates, balancing utility, urgency, waiting time, and geographic equity under national oversight.

The national network, operated under federal contract, that maintains the waiting list, sets allocation policies, and oversees member compliance with transplant standards.

Model state legislation, adopted with variations nationwide, that governs how individuals may donate organs and establishes the legal framework for first-person authorization and donor registries.

The process of disclosing a procedure's risks, benefits, and alternatives so a patient or authorized representative can voluntarily agree, a legal and ethical prerequisite for transplant.