HLA-DRB1 and leprosy: We identified four amino acids in HLA-DRβ1 (phenylalanine and aspartic acid in positions 13 and 57), HLA-B (glutamic acid in position 63), and HLA-A (lysine in position 19) that fully explained the associations of class I and class II alleles with leprosy in our sample (S5 and S6 Tables).