Associations of polymorphisms in CTLA-4 and IL-18 with liver diseases: evidence from a meta-analysis

Background Associations between polymorphisms in cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) / interleukin-18 (IL-18) and susceptibility to liver diseases were already reported by many publications. The aim of this meta-analysis was to clarify associations between polymorphisms in CTLA-4/IL-18 and liver diseases by combing the results of all relevant publications. Methods Eligible publications were searched from Pubmed, Embase, WOS and CNKI. The latest literature searching update was performed on 2nd October, 2019. We used Review Manager to combine the results of individual studies. Results Sixty-seven studies were included in this study. Combined results revealed that CTLA-4 rs231775 (dominant comparison: OR 0.83, 95 % CI 0.79-0.88; recessive comparison: OR 1.33, 95 % CI 1.23-1.43; allele comparison: OR 0.84, 95 % CI 0.78-0.90), IL-18 rs1946518 (dominant comparison: OR 0.85, 95 % CI 0.78-0.92; recessive comparison: OR 1.29, 95 % CI 1.13-1.48; allele comparison: OR 0.79, 95 % CI 0.71-0.88) and IL-18 rs187238 (dominant comparison: OR 1.28, 95 % CI 1.07-1.53; over-dominant comparison: OR 0.81, 95 % CI 0.68-0.97; allele comparison: OR 1.22, 95 % CI 1.07-1.39) polymorphisms were all significantly associated with liver diseases in the general population. We also obtained similar significant associations for CTLA-4 rs231775, CTLA-4 rs5742909, CTLA-4 rs3087243, IL-18 rs1946518 and IL-18 rs187238 polymorphisms in subgroup analyses. Conclusions Collectively, this meta-analysis proved that CTLA-4 rs231775, CTLA-4 rs5742909, CTLA-4 rs3087243, IL-18 rs1946518 and IL-18 rs187238 polymorphisms may confer susceptibility to various types of liver diseases.