Therapeutic Potential of The Low-dose IL-2 Through Targeting the Th17/Treg Axis in Primary Biliary Cholangitis Mice

Abstract Background/aims : Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease. The imbalance of Th17/Treg cells has been reported in PBC patients. low-dose IL-2 can alleviate disease severity through modulating CD4 + T cell subsets in patients with autoimmune diseases. Hence, the present study aimed to examine the effects and mechanism of low-dose IL-2 in PBC mouse models. Methods PBC models were induced in female C57BL/6 mice by two immunizations with 2OA-BSA at two-week intervals, and poly I: C every three days. PBC mice were divided into the IL-2 treated and untreated groups and low-dose IL-2 was injected at three different time points. Th17 and Tregs were analyzed by flow cytometry, and the related cytokines were analyzed by ELISA. Liver histopathology was examined by H&E and immunohistochemical staining. Results Twelve weeks after modeling, the serum AMA was positive and the ALP was significantly increased in PBC mice ( P ༜0.05). The pathology showed lymphocyte infiltration in the portal area, damage, and reactive proliferation of the small bile duct ( P ༜0.05). The flow cytometric showed the imbalance of Th17/Treg cells in the liver of PBC mice, with decreased Treg cells, increased Th17 cells and Th17/Treg ratio ( P < 0.05). After the low-dose IL-2 intervention, biochemical index and liver pathologies showed improvement at 12 weeks. Besides, the imbalance of Th17 and Treg cells recovered. Public database mining showed that Th17 cell differentiation may contribute to poor response in PBC patients. Conclusion Low-dose IL-2 can significantly improve liver biochemistry and pathology by reversing the imbalance of Th17 and Treg cells, suggesting that it may be a potential therapeutic target for PBC.