Use of Nakanuma staging and cytokeratin 7 staining for diagnosing recurrent primary biliary cholangitis after living‐donor liver transplantation

AIM Diagnosis of primary biliary cholangitis (PBC), which recurs in approximately 30% of liver transplant recipients, is histology-based, but no staging system has been established for recurrent PBC (rPBC). We used the Nakanuma staging system and cytokeratin 7 (CK7) staining to examine post-transplant liver biopsy specimens retrospectively and to evaluate histological features of rPBC. METHODS From 107 patients who underwent living donor liver transplantation for PBC, 60 recipients with 214 liver biopsies after 1-year post transplant were enrolled. Fibrosis, bile duct loss (BL), cholangitis activity, hepatitis activity, and CK7-positive hepatocytes were scored. Nakanuma staging was based on fibrosis and BL scores. We examined the correlation of scores and clinicolaboratory data among rPBC patients. We also evaluated whether chronological change of stage was correlated with liver-related failure. RESULTS Of 214 biopsies, 52 were protocol biopsy; 162 were episodic. Higher BL, cholangitis activity, and hepatitis activity scores were associated with rPBC diagnosis. At median follow up of 10.0 years (range 1.4-18.7 years), 29 (48%) patients were diagnosed with rPBC at 4.6 years (range 1.3-14.5 years). Liver-related failure occurred in five rPBC cases; three from rPBC, and two from chronic rejection. At rPBC diagnosis, higher BL and CK7 scores were more frequent in patients who developed liver-related failure than in other patients (P = 0.04, P