Polymorphisms in the TOLLIP Gene Influence Susceptibility to Cutaneous Leishmaniasis Caused by Leishmania guyanensis in the Amazonas State of Brazil

INTRODUCTION: The clinical outcome to Leishmania-infection is determined by the individual adaptive immune T helper cell responses and their interactions with parasitized host cells. An early development of a proinflammatory immune response (Th1 response) is necessary for Leishmania-infection resolution. The Toll-interacting protein (TOLLIP) regulates human Toll-like receptors signaling pathways by down regulating the proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) and inducing the ant-inflammatory cytokine interleukin-10 (IL-10). Polymorphisms in the TOLLIP gene are associated with infectious diseases. MATERIAL AND METHODS: The polymorphisms rs5743899 and rs3750920 in the TOLLIP gene were genotyped by polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis in 631 patients with cutaneous leishmaniasis (CL) caused by L. guyanensis and 530 individuals with no history of leishmaniasis. RESULTS: The G and T alleles of the rs5743899 and rs3750920 were more common in patients with CL than in healthy individuals (P = 2.6 x10(-8) ; odds ratio [OR], 1.7 [ 95% confidence interval (CI) 1.4–2.0] and P = 1.9 x10(-8) ; OR, 1.6 [95% CI 1.4–1.9] respectively). The r(2) and D’ linkage disequilibrium between the two polymorphisms are 0.05 and 0.473 with a confidence bounds of 0.37 to 0.57 respectively. CONCLUSION: The two polymorphisms are independently associated with an increased risk of developing CL.