Polymorphism in tumor necrosis factor genes associated with mucocutaneous leishmaniasis

Abstract

Recent studies have shown that mucocutaneous leishmaniasis (MCL), a severe and debilitating form of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis infection, is accompanied by high circulating levels of tumor necrosis factor (TNF)-α. Analysis of TNF polymorphisms in Venezuelan ACL patients and endemic unaffected controls unaffected controls demonstrates a high relative risk (RR) of 7.5 (P <0.001) of MCL disease in homozygotes for allele 2 of a polymorphism in intron 2 of the TNF-β gene, especially in females (RR = 9.5; P <0.001) compared with males (RR = 4; P <0.05). A significantly higher frequency (P <0.05) of allele 2 at the -308- basepair TNF-α gene polymorphism was also observed in MCL patients (0.18) compared with endemic control subjects (0.069), again associated with a high relative risk of disease (RR = 3.5; P <0.05) even in the heterozygous condition. Because both the TNF-α and TNF-β polymorphisms have previously been linked with functional differences in TNF-α levels, these data suggest that susceptibility to the mucocutaneous form of disease may be directly associated with regulatory polymorphisms affecting TNF-α production.