In a cross-match assay prior to renal transplantation, the recipient's serum is incubated with donor lymphocytes and complement is added. Cell lysis is observed. This positive cross-match indicates the presence of which type of pre-formed antibody?
- A Donor-specific anti-HLA antibodies (DSA) ✓
- B Anti-ABO isohemagglutinins
- C Anti-donor IgM cold agglutinins
- D Complement-fixing anti-T-cell antibodies
Correct answer: A. Donor-specific anti-HLA antibodies (DSA)
Explanation
The complement-dependent cytotoxicity (CDC) cross-match detects pre-formed donor-specific anti-HLA antibodies (DSA) in the recipient. A positive result is a contraindication to transplantation as it predicts hyperacute rejection within minutes to hours, mediated by antibody binding to endothelial HLA antigens followed by complement activation and thrombosis. ABO incompatibility is screened separately; cold agglutinins are not relevant to CDC cross-match.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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