Abstract: Objective To investigate the changes of peripheral blood T lymphocyte subsets and efficacy of ursodesoxycholic acid （UDCA） and vitamin D combination in treatment of patients with primary biliary cholangitis （PBC）. Methods A total of 92 patients with PBC were randomly divided into two groups in our hospital between January 2014 and December 2015. The patients in control group were treated with UDCA,while the patients in observation group with oral vitamin D and UDCA. The serum levels of 25-hydroxy vitamin D [25（OH）D],peripheral blood CD4⁺Treg and Th17 cells,and liver function index before and after treatment were obtained. Results Before treatment,the differences of all indexes between the two groups were not statistically significantly different （P>0.05）;At the end of one-year treatment,serum 25（OH）D levels and proportion of CD4⁺Treg cells in the observation group were significant higher（P<0.05）,while the proportion of Th17 cells,alanine aminotransferas （ALT）,aspartate transaminas （AST） level,alkaline phosphatas （ALP） level,and γ-glutamyltrans-ferase（GGT） levels were significantly lower than in the control group（P<0.05）；the proportion of CD4⁺Treg cells was significantly positively correlated with peripheral 25（OH）D and GGT levels（P<0.05）. Conclusion Vitamin D supplementation is beneficial for the treatment of PBC patients，which may be related to the activation of CD4+Treg cells.

Key words: Primary biliary cirrhosis, Vitamin D, T lymphocytes, Therapy