“…Alleles HLA-A*31 and HLA-B*55, with higher frequencies in the patients group, may also contribute to an impaired humoral response and thus be involved in susceptibility to leptospirosis, as they were associated with IgG subgroup deficiency (IgGSD) in a North American cohort [22]. Some HLA alleles outside the 8.1 haplotype with increased frequencies in the patient group have been associated with other infections, namely, HIV (HLA-B*55, HLA-B*58, and HLA-Cw*04 have a positive association with disease progression) [23], HBV (HLA-DRB1*13 appears to be protective) [24], HCV (HLA-Cw*04 is related to the persistence of the infection) [25], tuberculosis (HLA-DQB1*05 confers susceptibility) [26], dengue hemorrhagic fever (HLA-A*31 relates to susceptibility and HLA-DRB1*04 to protection) [27,28], and human papillomavirus (HPV; HLA-DRB1*04, HLA-DRB1*13, and HLA-DQB1*05 appear to provide some protection) [29,30]. The influence of HLA class I polymorphisms in the susceptibility to leptospirosis is probably related to alterations in the affinity of the HLA molecule binding site to the leptospiral antigens.…”