AbstractBackgroundThe present study sought to investigate the association between HLA-A, HLA-B and HLA-DRB1 genes and susceptibility or resistance to the different clinical manifestations of American cutaneous leishmaniasis (ACL) in southern Brazil.MethodsThe sample consisted of 169 patients with a diagnosis of ACL and 270 healthy subjects for comparison. HLA-A, HLA-B and HLA-DRB1 were typed by PCR-SSO reverse dot blot.ResultsResults showed a trend towards susceptibility to cutaneous lesions for alleles HLA-DRB1*13 (P=0.0228;Pc=0.3420; OR=1.66; 95%CI=1.08 – 2.56), HLA-B*35 (P=0.0218;Pc=0.6758; OR=1.67; 95%CI=1.08 – 2.29) and HLA-B*44 (P=0.0290;Pc=0.8990; OR=1.67; 95%CI=1.05 – 2.64). Subjects with allele HLA-B*27 (P=0.0180;Pc=0.5580; OR=7.1111; 95%CI=1.7850 – 28.3286) tended towards susceptibility to mucocutaneous lesions, those with HLA-B*49 (P=0.0101;Pc=0.3131; OR=6.4000; 95%CI=1.8472 – 22.1743) to recurrent ACL, and HLA-B*52 (P=0.0044;Pc=0.1360; OR=12.61; 95%CI=3.08 – 51.66), to re-infection. Presence of HLA-B*45 (P=0.0107;Pc=0.3317) tended to provide protection against the cutaneous form of ACL. The most frequent haplotypes that may be associated with susceptibility to ACL were A*02 B*44 DRB1*07 (P= 0.0236) and A*24 B*35 DRB1*01 (P= 0.0236).ConclusionSome Class I and Class II HLA genes appear to contribute towards susceptibility to and protection against different clinical manifestations of ACL. Other genetic marker studies may contribute toward future prophylactic and therapeutic interventions in ACL.