Association between interferon- γ3 +874 T/A polymorphism and susceptibility to autoimmune diseases: A meta-analysis

Objective The aim of this study was to explore whether the interferon (IFN)-γ3 +874 T/A polymorphism plays a role in modifying the risk of autoimmune diseases. Methods A meta-analysis was conducted on the association between the IFN-Î3 +874 T/A polymorphism and autoimmune diseases. Results Eighteen studies with a total of 2952 patients and 3832 controls were included in the meta-analysis. The meta-analysis revealed no association between autoimmune diseases and the IFN-γ3 +874 T allele in all study subjects (odds ratio (OR)=1.023, 95% confidence interval (CI) = 0.894-1.171, p = 0.738), but stratification by ethnicity indicated an association between the IFN-Î3 +874 T allele and autoimmune diseases in Latin American subjects (OR = 0.780, 95% CI = 0.629-0.953, p = 0.015). Meta-analysis also revealed an association between autoimmune diseases and the IFN-γ3 +874 T/A polymorphism in Caucasian and Middle Eastern subjects under a dominant inheritance model (OR = 0.686, 95% CI = 0.489-0.964, p = 0.003; OR = 1.414, 95% CI = 1.102-1.813, p = 0.006). Meta-analysis by autoimmune disease type indicated an association between ITP and the IFN-γ3 +874 T allele (OR = 1.753, 95% CI = 1.228-2.503, p = 0.002), but not for vasculitis, vitiligo, and auto-immune thyroid disease. Meta-analysis also showed a significant association between the IFN-γ3 +874 T/A polymorphism and systemic lupus erythematosus (SLE) under the dominant model (OR = 1.668, 95% CI = 1.114-2.497, p = 0.013). Conclusions This meta-analysis indicates that the IFN-γ3 +874 T/A polymorphism may play a significant role in modifying the risk of autoimmune diseases in Caucasian, Latin American, and Middle Eastern subjects, and in particular shows that the IFN-γ3 +874 T/A polymorphism is associated with increased genetic susceptibility to idiopathic thrombocytopenic purpura and SLE.