ABTC CCTN key terms

A calculated percentage indicating how many potential donors in a reference population have HLA antigens the candidate's antibodies would react against, estimating the breadth of sensitization before transplant.

A modern sensitization measure that weights each unacceptable HLA antigen by its actual frequency in the donor pool, giving a more accurate estimate of the chance of a compatible donor offer.

Development of antibodies against foreign HLA from prior transfusion, pregnancy, or transplantation, which narrows the compatible donor pool and raises immunologic risk.

A laboratory test mixing recipient serum with donor lymphocytes to detect preformed antibodies that could cause immediate graft injury; a positive result generally contraindicates transplant.

Comparison of donor and recipient human leukocyte antigen alleles, especially A, B, and DR, used to estimate immunologic compatibility and guide organ allocation.

The highly polymorphic cell-surface protein system that presents antigens to the immune system and is the principal target of transplant rejection responses.

Rapid graft destruction occurring within minutes to hours from preformed recipient antibodies activating complement against donor endothelium; the graft is usually unsalvageable and must be removed.

Immune-mediated graft injury developing days to months after transplant, classified as cellular or antibody-mediated, and typically treated with augmented immunosuppression.

Progressive, often irreversible graft dysfunction from longstanding immune and nonimmune injury, marked by fibrosis, vasculopathy, and declining organ function over months to years.

Antibodies directed at the specific HLA antigens of the transplanted organ, associated with antibody-mediated rejection and worse long-term graft survival.

Graft injury caused by donor-specific antibodies binding graft endothelium, producing complement activation, capillary inflammation, and dysfunction; diagnosed with histology and antibody testing.

Intensive immunosuppression given at the time of transplant, often a lymphocyte-depleting agent or IL-2 receptor blocker, to reduce early acute rejection risk.

Long-term combination drug regimen, typically a calcineurin inhibitor plus an antimetabolite and corticosteroid, used to prevent rejection while preserving enough immunity to fight infection.

A calcineurin inhibitor that blocks T-cell activation and is a cornerstone of maintenance immunosuppression; requires therapeutic drug monitoring because of narrow therapeutic range and nephrotoxicity.

An antimetabolite that inhibits lymphocyte proliferation, commonly paired with a calcineurin inhibitor; associated with gastrointestinal upset, bone marrow suppression, and teratogenicity.

Dose-related kidney injury, hypertension, tremor, and metabolic disturbances caused by tacrolimus or cyclosporine, managed by adjusting levels rather than simply escalating therapy.

Serial measurement of blood levels of narrow-index immunosuppressants to keep concentrations within a target range, balancing rejection risk against toxicity.

Infection by organisms that rarely cause disease in immunocompetent hosts, such as cytomegalovirus, Pneumocystis, or aspergillus, occurring when immunosuppression weakens host defenses.

A herpesvirus that causes significant morbidity after transplant, ranging from asymptomatic viremia to colitis, pneumonitis, and retinitis; managed with prophylaxis, monitoring, and preemptive treatment.

Preventive antimicrobial or antiviral therapy given after transplant to reduce the risk of specific infections during periods of greatest immunosuppression.

A spectrum of lymphoid proliferations arising after transplant, usually driven by Epstein-Barr virus in the setting of immunosuppression; treatment includes reducing immunosuppression and targeted therapy.

Donor immune cells attacking recipient tissues, most common after hematopoietic stem cell transplant, producing skin, gastrointestinal, and liver injury; prevented by matching and immunosuppression.

Progressive small-airway obstruction and declining lung function reflecting chronic lung allograft dysfunction, a major barrier to long-term survival after lung transplant.

Structured medical, psychosocial, and financial assessment of a volunteer organ donor to confirm acceptable risk, voluntariness, and absence of coercion before donation.

Assessment of a transplant candidate's mental health, substance use, social support, and adherence capacity to identify barriers and plan interventions before and after transplant.

The process of giving a patient or donor complete information about risks, benefits, and alternatives so they can voluntarily agree to a procedure or treatment.

The system that matches available organs to candidates using medical urgency, waiting time, compatibility, and geographic factors according to published policy.

A score derived from bilirubin, creatinine, and INR used to rank liver transplant candidates by short-term mortality risk and guide organ allocation.

A condition such as active malignancy, uncontrolled infection, or severe irreversible comorbidity that makes transplant unlikely to succeed or unacceptably risky.

The degree to which a patient follows the prescribed medication, monitoring, and lifestyle regimen; poor adherence is a leading cause of late rejection and graft loss.

Scheduled monitoring through laboratory tests, drug levels, imaging, or protocol biopsies to detect rejection or graft dysfunction before clinical symptoms appear.

Loss of adequate organ function requiring retransplant, dialysis, or other replacement therapy, caused by rejection, infection, technical complications, or recurrent disease.

A specialized nurse or clinician who manages candidate evaluation, waitlist logistics, education, and post-transplant follow-up across the care continuum.

The obligation to allocate scarce organs to achieve the greatest overall benefit, balancing urgency against expected outcomes and resource stewardship.

The risk of death while awaiting transplant, a key driver of allocation urgency and a metric used to evaluate program performance.