Systemic lupus erythematosus and toll-like receptor 9 polymorphisms: A meta-analysis of genetic association studies.

Objective: This study aimed to examine whether polymorphisms in toll-like receptor 9 (TLR9) contribute to vulnerability to systemic lupus erythematosus (SLE).

Methods: We searched the MEDLINE, Embase, and Web of Science databases for relevant articles. We conducted a meta-analysis to examine the association between the TLR9 rs187084, rs352139, rs352140, and rs5743836 polymorphisms and SLE risk.

Results: A total of 5447 patients with SLE and 6588 control participants across 26 trials from 24 articles were included. The TLR9 rs187084 T allele was significantly associated with SLE (odds ratio, 1.146; 95% confidence interval, 1.033-1.273; = 0.010). In a meta-analysis, the TLR9 rs187084 T allele was associated with SLE in the Asian population but not in the Arab population, demonstrating the existence of ethnicity-specific effects. Using homozygote contrast and recessive models, the researchers also found that the TLR9 rs187084 T/C polymorphism was associated with SLE. The TLR9 rs352139 G allele was not associated with SLE in this meta-analysis. After accounting for ethnic differences, we found that the TLR9 rs352139 G allele was not associated with SLE in Asians and Arabs. Furthermore, homozygote contrast and dominant models found no association between the TLR9 rs352139 G/A polymorphism and SLE. TLR9 polymorphisms at rs352140 and rs5743836 were not associated with an increased risk of SLE in any genetic prediction model, including people of Asian, European, or Latin American ancestry.

Conclusions: SLE susceptibility is associated with the TLR9 rs187084 polymorphism in the Asian population and the rs187084, rs352139, rs352140, and rs5743836 polymorphisms in the Asian, European, and Latin American populations, respectively.