The remaining 21 studies (8, 21–40) met with inclusion criteria for this analysis and were thus incorporated into this study, including 13 pertaining to the TNF-α rs361525 polymorphism (5, 5, and 2 case-control studies related to PBC, HBV, and ALC, respectively) and 9 pertaining to the IFN-γ rs2430561 polymorphism. The gene discussed is TNF; the disease is primary biliary cholangitis.