During HLA typing for renal transplantation, a prospective recipient has a positive cross-match with the donor's T-lymphocytes using complement-dependent cytotoxicity (CDC). The same serum gives a negative B-cell cross-match. What is the most appropriate next step?

• A Proceed with transplantation since B-cell cross-match is negative
• B Perform desensitization with plasmapheresis and proceed after T-cell cross-match turns negative
• C Abort transplantation; a positive T-cell CDC cross-match is an absolute contraindication due to risk of hyperacute rejection ✓
• D The finding indicates non-specific cytotoxicity; repeat the test after three months

Explanation

A positive T-cell CDC cross-match indicates the recipient harbours pre-formed antibodies (usually anti-HLA class I) against donor T-cell antigens. Transplanting across a positive T-cell cross-match almost invariably leads to hyperacute rejection mediated by complement activation within minutes to hours, destroying the graft. This is considered an absolute contraindication. The negative B-cell cross-match simply means no high-titre anti-HLA class II antibodies are present, but the T-cell finding alone is decisive.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.