Human leukocyte antigen and leprosy: study in northern Louisiana and review.

We examined the relationship of human leukocyte antigen (HLA) phenotype to leprosy in six sporadic cases in northern Louisiana and in the world literature through pooling of the results of several studies. We found that HLA antigens DR2 and DQwl were associated with leprosy in the six cases in northern Louisiana (relative risks, 4.57 for DR2 and 4.53 for DQwl), but the results are not statistically significant. We pooled the Louisiana study and other population studies of HLA and leprosy. The results of the pooling show DR2 and DQwl to be associated with leprosy (relative risks, 2.65 for DR2 and 2.73 for DQwl), and these associations are highly statistically significant (P less than 1 x 10(-8) for DR2 and P = 3.6 x 10(-8) for DQwl). Further, we pooled studies of lepromatous leprosy patients vs. controls and studies of tuberculoid leprosy patients vs. controls and found that DR2 and DQwl are associated with both the lepromatous and the tuberculoid forms of leprosy and that these associations are statistically significant. We consider the associations of DR2 and DQwl in these population studies to be evidence for an HLA-associated genetic influence on susceptibility to leprosy.