Differences in the distribution of HLA antigens in localized and generalized form of onchocerciasis.

Fifty-nine unrelated Liberians have been studied for human leukocyte antigens (HLA). Twenty-three individuals were classified as localized and 24 as generalized onchocerciasis, and the remaining 12 subjects showed no signs of the infection. HLA-typing documented differences in phenotype frequencies for class I (A, B, C) and class II (DR) antigens between the 3 groups of tested subjects. The strongest differences were observed between the localized form and the group without infection with a predominance of HLA-B35 (52% vs. 25%), Cw4 (48% vs. 25%), DR3 (57% vs. 17%), DR5 (65% vs. 8%, DRw52 (96% vs. 33%), and a decrease of DR1 (4% vs. 42%). Differences could also be stated for distinct HLA antigen combinations comprising these relevant antigens. The findings in part hold also true for the comparison of the total group of onchocerciasis (localized plus generalized form) versus the group without infection, however, at a lower level of difference. This pilot study indicates that both forms of onchocerciasis represent different immunological types of host responsiveness.