A meta-analysis of the association of IL-6 -174 G/C and -572 G/C polymorphisms with systemic lupus erythematosus risk.

The results from previous studies on association of IL-6 -174 G/C and -572 G/C polymorphisms with the risk of systemic lupus erythematosus (SLE) remained inconsistent. Therefore, a meta-analysis was performed to assess the association between these two polymorphisms and SLE susceptibility. A literature-based search was conducted to identify all relevant studies. Pooled data were estimated by fixed- and random-effects models when appropriate. Nine publications were included in the meta-analysis, seven for -174 G/C polymorphism and three for -572 G/C polymorphism. The results indicated that IL-6 -174 G/C polymorphism was significantly associated with SLE risk for recessive model and allele analysis in overall populations (OR 1.64, 95 % CI 1.10-2.45, P = 0.016; and 1.34, 1.05-1.72, P = 0.019, respectively, for recessive model and allele analysis) or in Caucasians (OR 1.37, 95 % CI 1.04-1.82, P = 0.027; and 1.27, 1.04-1.54, P = 0.018, respectively, for recessive model and allele analysis). Also, significant association between IL-6 -572 G/C polymorphism and SLE was found under recessive model (OR 1.49, 95 % CI 1.10-2.01, P = 0.009), but not under dominant model and allele analysis (OR 1.05, 95 % CI 0.77-1.43, P = 0.750; and 1.21, 1.00-1.48, P = 0.054, respectively, for dominant model and allele analysis). Additionally, our meta-analysis showed that IL-6 -174 G/C polymorphism was significantly associated with discoid skin lesions (P < 0.05). The present study indicates that IL-6 -174 G/C and -572 G/C polymorphisms could be candidates for susceptibility to SLE. Furthermore, a large number of studies should be performed to explore the association of IL-6 polymorphisms with the risk and clinical characteristics of SLE patients in different ethnics.