Abstract: Objective The aim of this study was to explore bile acid (BA) composition changes and their impact of response to immunosuppressant or ursodeoxycholic acid (UCDA) therapy in patients with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC). Methods 28 patients with AIH and 55 patients with PBC were encountered in our hospital between January 2020 and January 2023, and they received prednisone or UDCA therapy. Serum free BAs, including cholic acid (CA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA) and lithocholic acid (LCA), lycine-binding BAs(G-BAs), including glycocholic acid (GCA), glycodeoxycholic acid (GDCA), glycodeoxycholic acid (GCDCA) and glycodeoxycholic acid (GUDCA), and taurocholate-binding bile acid (T-BAs), including taurine cholic acid (TCA), taurine deoxycholic acid (TDCA), taurine deoxycholic acid (TCDCA) and taurine lithocholic acid (TLCA) levels were detected by liquid chromatography tandem mass spectrometry. Results By end of six month treatment, complete response to therapy in patients with AIH was found in 20 cases (71.4%) and in patients with PBC was found in 42 cases (76.4%); serum CA, CDCA, UDCA and LCA levels in AIH responders were (1.6±0.5)ng/ml, (2.6±0.4)ng/ml, (2.0±0.3)ng/ml and (0.7±0.4)ng/ml, all significantly lower than [(2.4±0.7)ng/ml, (2.9±0.4)ng/ml, (2.4±1.0)ng/ml and (0.9±0.7)ng/ml, respectively, P<0.05], serum GCA, GDCA, GCDCA and GUDCA levels were (1.3±0.5)ng/ml, (2.6±0.3)ng/ml, (2.9±0.3)ng/ml and (1.6±0.5)ng/ml, all significantly lower than [(3.0±1.0)ng/ml, (3.2±0.6)ng/ml, (3.8±0.8)ng/ml and (2.6±1.2)ng/ml, respectively, P<0.05], and serum TCA, TDCA, TCDCA and TLCA levels were (0.5±0.1)ng/ml, (2.6±0.2)ng/ml, (2.5±0.3)ng/ml and (0.1±0.0)ng/ml, all significantly lower than [(2.1±1.2)ng/ml, (3.3±0.6)ng/ml, (2.7±0.4)ng/ml and (0.4±0.1)ng/ml, respectively, P<0.05] in non-responders; serum CA, CDCA, UDCA and LCA levels in PBC responders were(1.7±0.4)ng/ml, (2.7±0.4)ng/ml, (2.1±0.4)ng/ml and (0.8±0.4)ng/ml, all significantly lower than [(2.3±0.9)ng/ml, (3.0±0.4)ng/ml, (2.5±0.7)ng/ml and (1.3±0.7)ng/ml, respectively, P<0.05], serum GCA, GDCA, GCDCA and GUDCA levels were (1.4±0.7)ng/ml, (2.6±0.4)ng/ml, (3.0±0.5)ng/ml and (2.0±0.9)ng/ml, all significantly lower than [(2.9±0.9)ng/ml, (3.2±0.5)ng/ml, (3.8±0.7)ng/ml and (3.0±1.1)ng/ml, respectively, P<0.05], and serum TCA, TDCA, TCDCA and TLCA levels were (0.5±0.2)ng/ml, (2.7±0.3)ng/ml, (2.5±0.4)ng/ml and (0.2±0.1)ng/ml, all significantly lower than [(2.1±0.9)ng/ml, (3.2±0.5)ng/ml, (2.8±0.4)ng/ml and (0.5±0.2)ng/ml, respectively, P<0.05] in non-responders. Conclusion There are significant differences in serum bile acid levels between patients with PBC and with AIH, and serum BAs changes might be involved in pathogenesis of autoimmune liver diseases, and have some influence on outcomes of the diseases.

Key words: Autoimmune hepatitis, Primary biliary cholangitis, Bile acids, Ursodeoxycholic acid, Immunosuppressant, Therapy, Response