Meta-analysis of -308G > A polymorphism in TNFα gene and susceptibility to leishmaniasis

The clinical spectrum of leishmaniasis depends on several factors, including Leishmania species and immunogenetic factors. Tumor necrosis factor α (TNFα) plays a central role in immunity against intracellular infections. Many studies have reported that TNFα-308G > A polymorphism is associated with susceptibility to intracellular infections and influences TNFα production. Some studies on the implications of TNFα-308G > A polymorphism in the susceptibility to cutaneous leishmaniasis and visceral leishmaniasis showed controversial results. To draw an overall conclusion using accurate data analysis by increasing the number of cases studied, a meta-analysis was performed based on data from the studies included in the analysis. A total of 1264 patients and 2350 controls were enrolled in the meta-analysis. The results showed no significant association between allele G and allele A of -308G > A polymorphism and leishmaniasis by taking the two subgroups separately [OR_CL = 0.99 (0.84-1.18) and OR_VL = 1.19 (0.88-1.59)] or together [OR = 1.04 (0.90-1.20)]. This meta-analysis insinuates the absence of statistical evidence for an association between allele G and allele A of TNFα-308G > A polymorphism and Leishmania infection outcome. This suggests that TNFα, despite its crucial role in the immune response against Leishmania infection, is not the sole determinant factor. Other factors, such as gene-gene and gene-environment interactions, receptors, and signaling pathway efficiency, may influence TNFα function.