Hyperacute rejection in renal transplantation occurs within minutes to hours of reperfusion and is mediated by:
- A CD8+ cytotoxic T-lymphocytes targeting donor HLA antigens
- B Preformed recipient anti-donor antibodies activating complement (type II hypersensitivity) ✓
- C NK cell-mediated lysis of donor endothelium
- D Neutrophil-mediated ischaemia-reperfusion injury
Correct answer: B. Preformed recipient anti-donor antibodies activating complement (type II hypersensitivity)
Explanation
Hyperacute rejection is caused by preformed recipient antibodies (anti-ABO or anti-HLA class I) binding to donor vascular endothelium, activating complement and the coagulation cascade, leading to widespread intravascular thrombosis and irreversible graft loss within minutes. It is prevented by ABO compatibility testing and pre-transplant cross-matching. Acute rejection is T-cell mediated; chronic rejection involves antibody-mediated intimal proliferation.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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