Association between an HLA haplotype and low responsiveness to schistosomal worm antigen in man.

Immune responsiveness to schistosomal worm antigen was investigated in the individuals infected with Schistosoma japonicum by measuring the antigen-specific proliferative response of the peripheral T lymphocytes in vitro. Out of 57 infected individuals, 10 (17.5%) were low responders, whereas 47 (82.5%) were high responders to this antigen. The strong association between the HLA-Aw24-Bw52-Dw12 haplotype and the low responder group was demonstrated. Because the association of the low responder group was strongest with the HLA-D specificity, Dw12, and because the HLA-D region was assumed to be comparable to the I region of the murine H-2 complex, it was suggested that the low responsiveness to schistosomal worm antigen was controlled by a single dominant immune suppression gene that was in strong linkage disequilibrium with HLA-Dw12.