In HLA typing for renal transplantation, the mixed lymphocyte reaction (MLR) tests specifically for compatibility at which HLA locus?

• A HLA-A
• B HLA-B
• C HLA-C
• D HLA-DR (Class II) ✓

Explanation

The mixed lymphocyte reaction (MLR/MLC) primarily detects incompatibility at HLA Class II loci, especially HLA-DR and HLA-DQ, because CD4+ T helper cells respond to allogeneic Class II antigens on stimulator cells. HLA-A and HLA-B are Class I antigens primarily detected by serological or molecular typing methods, not by MLR. MLR is now largely replaced by molecular HLA typing but remains conceptually important for NEET PG.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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