Diversity of humoral responses to the centromere proteins among HCV-related chronic liver disease, PBC and AIH patients

Summary Background Anticentromere antibodies (ACAs) have been observed in patients with autoimmune hepatitis (AIH) and hepatitis C virus (HCV)-related chronic liver disease (CLD-C) as well as those with primary biliary cirrhosis (PBC). However, little is known about the differences in immune responses to the centromere proteins among these liver diseases. Objective By synthesizing recombinant proteins consisting of the N- and C-termini of major centromere proteins, we investigated the humoral responses against them in each disease. Results Eight of the 754 (1%) patients with CLD-C, 14 of the 57 (25%) patients with PBC and six of the 38 (16%) patients with AIH were seropositive for ACAs. There were no significant differences in ACA titers determined by an indirect immunofluorescent method among the groups of patients with CLD-C, PBC and AIH. However, the analysis of immunoreactivities against each recombinant protein revealed that the titers of IgG-subclass autoantibodies against the C-terminus of centromere protein (CENP)-B were significantly higher in the CLD-C patients than in the AIH patients. Likewise, the titers of IgM-subclass autoantibodies against the N-terminus of CENP-A were significantly higher in the PBC group than in the CLD-C group. The ACA-positive patients who developed liver cirrhosis had significantly higher titers of the IgA-subclass autoantibodies against the C-terminus of CENP-C than those who did not. Conclusion These findings suggest that immunoreactivities against the fragments of centromere proteins show distinct patterns among CLD-C, PBC and AIH and that the determination of immunoreactivities against the centromere proteins may be useful for the prediction of disease progression.