Department of Intensive Care Unit, The First Hospital of China Medical University , Shenyang, People's Republic of China.
Interleukin-4 (IL-4) is a pleiotropic cytokine that plays an important role in the immune system. Emerging evidences have shown that the common polymorphism (-590C/T; rs2243250 C>T) in the IL-4 gene may play an important role in the development of various liver diseases, but individually published studies revealed inconclusive results. This meta-analysis aims to derive a more precise estimation of the association between the IL-4 -590C/T polymorphism and susceptibility to liver disease. A literature search of PubMed, Embase, Web of Science and China BioMedicine databases was conducted on articles published before January 1st, 2013. Crude odds ratio with 95% confidence intervals were calculated to assess the strength of this association. Ten case-control studies were assessed with a total 1,140 patients and 1,649 healthy controls. The meta-analysis results indicated that the IL-4 -590T polymorphism might increase the risks of hepatitis B (HBV) and hepatitis C (HCV) infections. Further subgroup analyses showed significant associations between the IL-4 -590T polymorphism and increased risks of liver diseases among Caucasian populations, but similar associations were not found among Asian populations. Univariate and multivariate meta-regression analyses showed that differences in ethnicity and clinical subtype are the major sources of heterogeneity. No publication bias was detected in this meta-analysis. In conclusion, the current meta-analysis indicates that the IL-4 -590T polymorphism may play an important role in increasing HBV and HCV infection risks, especially among Caucasian populations.