Meta-analysis of IL-6 -174G/C polymorphism and psoriasis risk

Previous studies examining the association between interleukin-6 (IL-6) -174G/C polymorphism and psoriasis risk have produced inconsistent results. The aim of this study was to offer a comprehensive review of the association between IL-6 -174G/C polymorphism and psoriasis risk through a meta-analysis. Literature search of PubMed and Embase databases was conducted to identify all eligible studies published before October 29, 2015. Four case-control studies involving 651 psoriasis cases and 552 controls were included in this meta-analysis. Data were extracted, and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the associations. Combined analysis revealed a significant association between this polymorphism and psoriasis risk under the recessive model (OR = 1.69, 95%CI = 1.12-2.55, P = 0.013 for GG vs GC + CC), and the heterozygous comparison model (OR = 1.70, 95%CI = 1.29-2.23, P < 0.001 for GG vs GC). However, no significant association was observed under the allelic model (OR = 1.37, 95%CI = 0.99-1.89, P = 0.060 for G vs C), the dominant model (OR = 1.25, 95%CI = 0.92-1.71, P = 0.152 for GG + GC vs CC), and the homozygote comparison model (OR = 1.62, 95%CI = 0.79-3.32, P = 0.186 for GG vs CC). We conclude that the IL-6 -174G/C polymorphism contributes to psoriasis risk. However, further studies should be performed to validate our results.