Prevalence of Primary Biliary Cholangitis in a Cohort of Primary Sjögren’s Syndrome Patients

Objective To analyze the prevalence and clinical progression of primary biliary cholangitis (PBC) in patients with primary Sjögren's syndrome (pSS) and possible associations between biochemical and immunological features and the development of PBC. Methods We retrospectively reviewed a cohort of 115 pSS patients followed up in an outpatient clinic from 1987 to 2020, without a history of liver disease, and looked for the presence of PBC through analysis of several biochemical, immunological, and histologic characteristics. Results Twenty patients (17.4%) had chronic cholestatic liver biochemistry. After exclusion of extrahepatic liver disease by abdominal ultrasound, 13 of them were tested for antimitochondrial autoantibodies (AMA) detected by indirect immunofluorescence (IF), of which five tested positive, fulfilling the diagnostic criteria for PBC. Three of the five PBC patients and three of the eight chronic cholestasis AMA-negative patients were further investigated with liver biopsy, which showed features of PBC in all three PBC patients and in one of the chronic cholestasis AMA-negative patients, allowing for the diagnosis of AMA-negative PBC in the latter. The remaining two AMA-negative patients had liver histology compatible with autoimmune hepatitis and unspecific findings, respectively. Overall, six (5.2%) patients with pSS had AMA-positive PBC (n=5) or AMA-negative PBC (n=1). Comparing immunological characteristics between PBC and non-PBC patients, we found that PBC patients had a higher mean maximum erythrocyte sedimentation rate (ESR) during follow-up than patients without PBC. All PBC patients were treated with ursodeoxycholic acid (UDCA) and after treatment with UDCA, only one patient showed biochemical and clinical progression of PBC, with increasing alkaline phosphatase and total bilirubin levels, eventually progressing to cirrhosis. Conclusions Among patients with pSS, PBC had an overall prevalence of six of 115 (5.2%). Higher ESR was a feature associated with PBC patients. In our cohort, after initiation of UDCA treatment, PBC showed predominantly slow progress, with only one patient progressing to cirrhosis during follow-up.