Abstract: Objective The aim of this study was to explore plasma cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene polymorphisms in patients with primary biliary cholangitis(PBC). Methods A total of 30 patients with PBC and 35 healthy persons were included in our hospital between September 2015 and December 2020, and the gene polymorphisms of CTLA-4 at rs231775, rs4675369 and rs7599230 loci were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The Logistic regression analysis was applied to reveal the risk factors for PCB occurrence. Results The percentages of CTLA-4 genotypes (CC, CT, TT) at rs7599230 locus in patients with PBC were 16.7%, 46.7% and 36.6%, not significantly different compared with those in healthy persons (20.0%,45.7%, 34.3%, respectively, P>0.05), and the percentages of alleles (C, T) in patients with PBC were 40.0% and 60.0%, also not significantly different compared with those in healthy individuals (42.9% and 57.1%, respectively, P>0.05); the percentages of CTLA-4 genotype GG and allele G at rs231775 locus in patients with PBC were 40.0% and 61.7%, significantly higher than 14.2% and 35.7% in healthy persons (P<0.05), while the percentages of of AA genotype and allele A were 16.7% and 38.3%, significantly lower than 42.9% and 64.3% in healthy persons (P<0.05); the percentages of CTLA-4 genotype GG and allele G at rs4675369 locus in patients with PBC were 43.3% and 65.0%, significantly higher than 17.1% and 41.4% in healthy individuals (P<0.05), while the percentages of AA genotype and allele A were 13.4% and 35.0%, significantly lower than 34.3% and 58.6% in healthy control (P<0.05); after the correction of gender and age by unconditional Logistic regression model, we found that the GG genotype at rs4675369 locus (OR: 1.523, 95%CI: 1.113-2.085) and the GG genotype at rs231775 locus (OR:1.636, 95%CI: 1.161-2.305) were the risk genotype for the occurrence of PBC. Conclusion Our findings suggest that the GG genotype at rs231775 and rs4675369 loci of CTLA-4 gene might be the susceptible genotype for PBC occurrence, and needs further investigation.

Key words: Primary biliary cholangitis, Cytotoxic T lymphocyte associated antige-4, Gene polymorphism, Susceptibility