HLA-linked control of predisposition to lepromatous leprosy.

In a study of the relation between HLA and lepromatous leprosy, HLA haplotype segregation was analyzed in 28 families with multiple cases of different types of leprosy. The inheritance of HLA-DR2, HLA-DR3, and HLA-MT1, which had previously been shown to be associated with susceptibility to leprosy or with a leprosy type, was analyzed separately. Segregation occurred in a significantly nonrandom fashion in both polar tuberculoid leprosy and lepromatous leprosy. This finding indicated HLA-encoded control of a predisposition to both of these forms of the disease. In both cases the segregation observed among healthy siblings was random. Thus, susceptibility to leprosy per se is probably not controlled by HLA-linked genes. HLA-DR3 was inherited preferentially by children with polar tuberculoid leprosy rather than lepromatous disease (P = .02), and HLA-MT1 was inherited preferentially by children with lepromatous leprosy (P = .04). The results confirmed the association of these genetic markers with leprosy type.