Primary biliary cirrhosis - Autoimmune hepatitis overlap syndrome: A rationale for corticosteroids use based on a nation-wide retrospective study in Japan

Aims: Primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) may simultaneously coexist in some patients, designated as PBC-AIH overlap syndrome. Previous studies suggest that combination therapy of ursodeoxycholic acid (UDCA) and corticosteroids may be effective. In the current study, we aimed to describe clinical features of these cases and to propose a rationale for combination treatment in PBC-AIH overlap. Methods: We enrolled patients with PBC-AIH overlap from eight referral centers for liver diseases in Japan, and clinical, biochemical and immunological features were examined. Liver histology of all patients at diagnosis were analyzed altogether in detail. Eighty-nine and 44 patients with PBC and AIH alone were included and served as controls. Results: We identified 33 patients with PBC-AIH overlap. The mean follow-up period was 6.1years. On liver histology, the HA (hepatitis activity) score was significantly higher than the CA (cholangitis activity) score (P<0.001). At the end of the follow-up period, corticosteroids were used in 23 patients (72%), and neither liver-related death nor liver transplantation had been noted. The sensitivity and specificity of the simplified AIH scoring system for prediction of patients who required corticosteroids during clinical course was 92% and 75% in the training set (n=17), and 91% and 80% in the validation set (n=16) of overlap. Only 3% of PBC patients were diagnosed as having indication for corticosteroid use. Conclusion: In PBC-AIH overlap, AIH-like features are dominant in liver histology. The simplified AIH scoring system could predict patients who needed corticosteroids with a higher specificity.