Objective To evaluate the changes of adenosine metabolism pathway related molecules and their contribution to inflammatory injury in primary biliary cholangitis (PBC).Methods The consecutive samples of 49 subjects with PBC from The First People's Hospital of Taicang and The Second People's Hospital of Changshu were recruited from October 2016 to October 2017,and 36 healthy controls were involved in this study.The expression of CD39 and CD73 on CD4+T cells and Foxp3 + regulatory T cells were assayed by flow cytometry and the concentration of adenosine triphosphate (ATP) in serum was analyzed by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS).The correlations between Tregs,ATP and liver function were analyzed,i.e.,alanine aminotransferase (ALT),aspartate aminotransferase (AST),gamma-glutamyltransferase (GGT),alkaline phosphatase (ALP) and Mayo scores.Results In the patients with PBC,low proportions of CD4+CD39+T cells were noted compared with healthy controls [(5.28 ± 1.92) ％ vs (11.0l ± 3.19) ％,t =10.25,P ＜ 0.01].The patients with PBC also had significantly low proportion of CD4+CD25 + Foxp3+ CD39+ T cells compared with healthy controls [(23.75 ± 9.48) ％ vs (54.68 ± 5.18) ％,t =13.79,P ＜0.01].No significant difference of the proportion of CD4+CD73+T or CD4+CD25+ Foxp3+CD39+T cells was found between PBC and control groups (t values were 2.235 and 1.083,P ＞ 0.05).The level of serum ATP was higher in the patients with PBC than that of healthy controls [(200.28 ± 79.41) μg/L vs (89.20 ± 33.76) μg/L,t =8.367,P ＜ 0.01].A significant correlation was demonstrated between the proportion of CD39 + Treg in total Treg cells and the levels of ATP (r =-0.413,P =0.003),GGT (r=-0.378,P=0.007) and Mayo score (r=-0.382,P=0.007).Conclusion The low proportion of CD39+ Treg cells may contribute to the down-regulation of ATP hydrolysis in the patients with PBC.No significant change of CD73 + Treg cells was found in PBC patients.