RESUMO
BACKGROUND: It is unclear whether autoimmune cholangitis (AIC) is a separate disease entity or primary biliary cirrhosis (PBC) without antimitochondrial antibodies (AMA) since fluctuation of AMA titres by immunofluorescence (IF) is often observed during the course of PBC. The aim of this study was to determine the serial changes in AMA profiles during the course of initially diagnosed PBC or AIC. METHODS: In this prospective study, 32 patients with PBC or AIC were followed-up for at least 20 months and tested for AMA by IF, enzyme-linked immunosorbent assay (ELISA), and immunoblotting (IB). RESULTS: When positive AMA result was defined as 'AMA by IF positive', 'AMA by IF and/or ELISA positive', and 'AMA by IB positive', the diagnosis of PBC or AIC did not change in 78%, 91%, and 97%, respectively, throughout follow-up. However, the diagnosis changed in one patient, and three patients were diagnosed as AIC throughout follow-up, despite the use of all three assays. CONCLUSIONS: Our results suggested that the diagnosis of PBC and AIC was dependent on the 'phase' of the respective disease in 22% of the patients when negative AMA result was defined as 'AMA by IF negative'. This may result in recommending IB analysis before making the diagnosis of AIC.
