Before a deceased donor renal transplant, the complement-dependent cytotoxicity crossmatch between recipient serum and donor lymphocytes is positive. What does this result indicate?

• A ABO blood group incompatibility between donor and recipient
• B Latent cytomegalovirus infection in the donor
• C Poor HLA matching at the DR locus only
• D Preformed circulating cytotoxic antibodies against donor HLA antigens, a contraindication to proceeding ✓

Explanation

A positive lymphocytotoxic crossmatch means the recipient's serum contains preformed antibodies that bind donor lymphocytes and fix complement, lysing them. Transplanting across a positive crossmatch carries a very high risk of hyperacute rejection and is an absolute contraindication in routine practice. ABO compatibility is assessed separately, and HLA matching is determined by tissue typing, not the crossmatch. This test detects sensitisation from prior transfusions, pregnancies, or failed grafts.

Reference: Schwartz Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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