Update on the association between interleukin-12 p40 gene polymorphism and risk of psoriasis: A meta-analysis

BackgroundPsoriasis is a common inflammatory skin disease with a strong genetic component. Interleukin (IL)-12 is one of the key cytokines in immune regulation and is overexpressed in psoriasis. The aim of this study was to update the meta-analysis for the association between IL-12 p40 gene (IL-12B) rs3212227 polymorphism and risk of psoriasis.MethodsWe performed a literature search from inception to December 2014. Review Manger 5.2 was used for meta-analysis. Odds ratios and their 95% confidence intervals were calculated under five genotype models: C versus A, CC + AC versus AA, CC versus AA + AC, CC versus AA, and CC versus AC. In addition, subgroup analyses were performed by ethnicity.ResultsNine studies involving 6520 psoriasis patients and 11,150 healthy controls were included. Two included studies were newly published studies, which were not analyzed in previous meta-analyses. The overall meta-analysis showed the significant association between psoriasis and IL-12B rs3212227 in all the genotype models, indicating that carriers of genotype CC or allele C had a less risk of psoriasis. Meanwhile, subgroup analyses showed this association existed in not only European, but also Asian populations.ConclusionThis meta-analysis demonstrated that IL-12B rs3212227 was associated with the risk of psoriasis in European and Asian populations.