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SU13.1-4 | Transplantation — Practice Quiz
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Minutes after a deceased-donor kidney is revascularised in the recipient, the graft turns mottled and blue, becomes flaccid and fails. This catastrophic, immediate loss is caused by recipient antibodies already present against donor antigens. Which type of rejection has occurred?
Correct. Hyperacute rejection occurs within minutes to hours because of pre-formed recipient antibodies (e.g. against ABO or HLA antigens) that bind donor endothelium and trigger thrombosis — which is why cross-matching is done before transplantation.
Hyperacute rejection (minutes–hours) is antibody-mediated by pre-formed antibodies; acute rejection (days–weeks) is largely T-cell mediated; chronic rejection (months–years) causes progressive graft fibrosis.
Immediate graft failure within minutes of revascularisation due to pre-formed antibodies against donor antigens is hyperacute rejection; pre-transplant cross-matching is performed precisely to prevent it.
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When matching a deceased donor to a kidney-transplant recipient, beyond ABO blood-group compatibility, the degree of matching at which set of cell-surface antigens most strongly influences the risk of immune rejection?
Correct. The human leukocyte antigens (HLA), encoded by the major histocompatibility complex, are the principal targets of the alloimmune response; closer HLA matching reduces rejection risk.
HLA (MHC) antigens are the major immunological barrier to transplantation; ABO compatibility and a negative cross-match are also required, but HLA matching most influences alloimmune rejection risk.
After ABO compatibility, it is the human leukocyte antigens (HLA / MHC) that most strongly determine rejection risk, because they are the main targets of the recipient's alloimmune response.
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A transplant recipient is started on tacrolimus. This agent suppresses rejection chiefly by inhibiting calcineurin, thereby blocking T-cell activation. To which class of immunosuppressive drugs does tacrolimus belong?
Correct. Tacrolimus (like ciclosporin) is a calcineurin inhibitor; it blocks calcineurin-dependent T-cell activation and is a mainstay of maintenance immunosuppression.
Maintenance immunosuppression typically combines a calcineurin inhibitor (tacrolimus/ciclosporin), an antiproliferative agent (mycophenolate/azathioprine) and a corticosteroid — distinct classes acting at different points of the immune response.
Tacrolimus inhibits calcineurin to block T-cell activation, placing it in the calcineurin-inhibitor class (along with ciclosporin).
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A maintenance immunosuppression regimen for an organ-transplant recipient classically combines three drug classes acting at different points of the immune response. Which combination represents this standard triple therapy?
Correct. Standard triple maintenance therapy combines a calcineurin inhibitor (e.g. tacrolimus), an antiproliferative agent (e.g. mycophenolate) and a corticosteroid (e.g. prednisolone), targeting complementary steps to maximise efficacy and limit toxicity.
Triple therapy (calcineurin inhibitor + antiproliferative + steroid) balances efficacy against the major hazards of immunosuppression — infection (including opportunistic) and malignancy.
Standard triple maintenance immunosuppression pairs a calcineurin inhibitor, an antiproliferative agent and a corticosteroid — three distinct classes acting at complementary points of the immune response.
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A 24-year-old man on a ventilator after a road traffic accident has lost all brainstem reflexes and is being assessed for deceased organ donation. Before donation can proceed, the law requires formal certification of which state?
Correct. Deceased-donor organ donation from a ventilated donor requires formal certification of brain-stem death by a designated board, as recognised and regulated under THOTA. This legal definition of death permits organ retrieval while circulation is artificially maintained.
Brain-stem death is the legally recognised basis (under THOTA) for deceased organ donation; its formal certification is what allows organ retrieval while the donor remains ventilated.
Donation from a ventilated, neurologically devastated donor requires formal certification of brain-stem death (brain death) — the legally recognised definition under THOTA that permits organ retrieval while circulation is maintained.
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In India, organ donation and transplantation — including the definition of brain death, regulation of living-related and deceased donation, and the prevention of commercial trade in organs — are governed principally by which legislation?
Correct. The Transplantation of Human Organs Act (THOTA), 1994, amended in 2011 (renamed the Transplantation of Human Organs and Tissues Act), is the governing framework — it recognises brain death, regulates living and deceased donation and prohibits commercial dealing in organs.
THOTA 1994 (amended 2011) is the legal backbone of Indian transplantation: it defines brain death, regulates living-related and deceased donation, and prohibits commercial organ trade.
Organ donation and transplantation in India are governed by the Transplantation of Human Organs Act (THOTA), 1994, amended in 2011 — covering brain-death recognition, regulation of donation and the ban on organ trade.
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