Abstract: Objective The aim of this study was to explore the diagnostic efficacy of peripheral blood regulatory T cells (Treg)/helper T cells 17 (Th17) and theirrelated cytokines in predicting significant liver fibrosis in patients with primary biliary cholangitis (PBC). Methods 59 patients with PBC and 59 healthy persons were encountered in our hospital between January 2019 and December 2021. All PBC patients underwent routine liver biopsy. The percentages of peripheral blood Treg/Th17 cells were detected by flow cytometry. Serum IL-10, IL-6 and IL-17 levels were detected by ELISA. The receiver operating characteristic (ROC) curves were drawn by SPSS 20.0 software, and the diagnostic performance of peripheral blood Treg/Th17 cell’s parameters in predicting significant liver fibrosis was evaluated by area under the curve (AUC). Results The percentages of peripheral blood Treg and Th17 cells, and Th17/Treg cell ratio in patients with PBC were(3.1±0.5)%, (5.9±0.9)% and (1.9±0.3), all significantly higher than [(1.6±0.3)%, (2.3±0.5)% and (1.4±0.1), respectively, P＜0.05] in healthy persons; serum IL-10, IL-6 and IL-17 levels in patients with PBC were (19.5±3.4)ng/L, (10.3±2.2)ng/L and (21.2±3.1)ng/L, all significantly higher than [(13.9±2.7)ng/L, (6.4±1.5)ng/L and (5.1±0.9)ng/L, respectively, P＜0.05] in healthy persons; the liver histopathological examination showed non-significant liver fibrosis in 20 cases, and significant liver fibrosis in 39 cases in our series; the percentages of cells and their related serum cytokine levels in patients with significant liver fibrosis were much higher than in those with non-significant liver fibrosis(P＜0.05); the ROC analysis demonstrated that the AUC was 0.956 when all the six parameter combination in predicting significant liver fibrosis in patients with PBC, much higher than 0.760, 0.746, 0.776, 0.747, 0.736 and 0.769 (P＜0.05) by any one of them. Conclusion The percentages of peripheral blood Treg and Th17 cells, and their related serum cytokine levels increase in patients with PBC, which might be related to liver fibrosis, and needs further investigation.

Key words: Primary biliary cholangitis, Liver fibrosis, Regulatory T cell, Helper T cell, Cytokines, Diagnosis