Association between the IL-6 gene polymorphism and tuberculosis risk: a meta-analysis

Background: The gene polymorphism of interleukin-6 (IL-6) has been shown to be implicated in tuberculosis susceptibility in many studies, but with conflicting results. This study aimed to provide more accurate estimation of the relationship between IL-6 gene polymorphism and tuberculosis risk through a meta-analysis Method: A literature search was performed in PubMed, EMBASE, and other databases. Data were retrieved, and pooled odds ratio (OR) with 95% CI were calculated. Statistical analyses were performed by using STATA 12.0. Results: Twelve publications with 2635 cases and 3049 controls were included. The pooled analysis demonstrated significant evidence of association between IL-6 (-174G/C) and low risk of tuberculosis in dominant model (CC+GC vs GG: OR =0.693, 95% CI 0.581-0.826, p<0.001). Subgroup analysis got similar results for IL-6 (-174G/C) in Asians and Latinos, but the significance did not exist in Caucasians. IL-6 (-572C/G) polymorphism was also associated with low risk of tuberculosis in dominant model (CC+GC vs GG: OR =0.719, 95% CI 0.577-0.896, p=0.003). No publication bias was detected in either of the polymorphisms. Conclusion: In summary, IL-6 -572 C/G polymorphism may be associated with a decreased risk of tuberculosis, and C allele is the protective factor against tuberculosis for IL-6 -174G/C among Asians and Latinos, but not in Caucasian population.