Lack of association of Toll-like receptor 9 polymorphisms with susceptibility to systemic lupus erythematosus in an Asian population: a meta-analysis

The association of Toll-like receptor 9 (TLR9) gene polymorphisms with systemic lupus erythematosus (SLE) risk remains controversial and ambiguous. To more precisely estimate the relationship between TLR9 gene polymorphisms and the susceptibility to SLE, a meta-analysis was performed. A total of seven independent studies were involved in this analysis. Meta-analysis was performed for three TLR9 gene polymorphisms (rs187084, rs352139, and rs352140). We have compared allele or genotype frequencies of the polymorphisms in SLE patients and controls. When available studies were pooled into the meta-analysis, there was no evidence showing a significant association between rs187084 and SLE risk in an Asian population (for C vs. T: OR = 0.81, P = 0.117; for CC vs. TT: OR = 0.71, P = 0.158; for CT vs. TT: OR = 0.86, P = 0.085; for CC + CT vs. TT: OR = 0.78, P = 0.093; for CC vs. CT + TT: OR = 0.81, P = 0.285). Similar results were found between rs352139 and SLE. No significant association was detected in any genetic model in the Asian population either (for G vs. A: OR = 1.11, P = 0.095; for GG vs. AA: OR = 1.32, P = 0.238; for GA vs. AA: OR = 1.17, P = 0.084; for GG + GA vs. AA: OR = 1.17, P = 0.073; for GG vs. GA + AA: OR = 1.17, P = 0.404). We found no association between TLR9 gene rs352140 polymorphism and SLE in the Asian population (for A vs. G: OR = 1.02, P = 0.728). In conclusion, there is still not enough evidence to indicate an association between TLR9 gene rs187084, rs352139, and rs352140 polymorphisms and the development of SLE in the Asian population.