A scoring system for primary biliary cirrhosis and its application for variant forms of autoimmune liver disease

Background: Although primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) are two independent autoimmune liver diseases, it is sometimes difficult to characterize the variant forms of autoimmune liver disease. A PBC scoring system, in combination with the AIH scoring system may be helpful to characterize such patients. Methods: A PBC scoring system was introduced that selected 14 categories characteristic of PBC. One hundred and thirty-four patients with PBC, 31 patients with autoimmune cholangitis (AIC), 22 patients with overlap syndrome, and 48 patients with AIH were included in the study. The AIC patients fulfilled the PBC criteria but were negative for anti-mitochondrial antibody and positive for anti-nuclear antibody. Overlap syndrome patients fulfilled both the PBC and AIH criteria. Results: The total scores (means ± SD) for the PBC, AIC, overlap syndrome, and AIH patients were 23.3 ± 4.7, 9.3 ± 4.4, 18.0 ± 5.9, and 3.6 ± 3.3, respectively. When definite and probable PBC patients were defined as those with a total score of over 17 and 9–17, respectively, all except for 1 patient could be classified as definite or probable PBC. Four of the 48 AIH patients were classified as probable PBC. PBC scores for the variant autoimmune liver diseases showed a wide deviation. Plotting both PBC and AIH scores in a rectangular coordinate enabled us to locate each patient with variant forms according to the deviation from classical PBC or AIH. Conclusions: The PBC scoring system might be useful in characterizing the features of variant forms of autoimmune liver disease. Received: March 6, 2002 / Accepted: June 14, 2002 Reprint requests to: K. Yamamoto Editorial on page 106