Candidate gene case-control and functional study shows macrophage inhibitory factor (MIF) polymorphism is associated with cutaneous leishmaniasis.

American tegumentary leishmaniasis (ATL) is an infectious disease caused mostly by Leishmania(Viannia)braziliensis in Southeast Brazil. The clinical manifestations are vast, ranging from asymptomatic to severe mucosal leishmaniasis (ML). It has been suggested that variation of the pathogen does not fully explain the response spectrum and the variability of clinical manifestations. Previous data have shown that host genetics also play a role in disease outcome. Herein, we have tested the association of TNF, IL10, IL12 and MIF single nucleotide polymorphisms (SNPs) using a case-control study design including 110 cutaneous leishmaniasis (CL) patients and 682 healthy subjects. The genotype-phenotype correlation was also assessed using leishmania antigens to stimulate peripheral blood mononuclear cells obtained from cured CL patients. Results demonstrated that the MIF -173C allele is associated with leishmaniasis outcome and also with lower levels of MIF in culture supernatants. Also, the TNF -308AA genotype was statistically increased among leishmaniasis patients. The results showed here suggest that the lower levels of MIF produced by MIF -173C carriers could influence the host-Leishmania interaction, favoring infection and disease progression. On the other hand, high TNF levels can contribute to tissue damage, consequently leading to skin lesions.