Background: Besides the autoantibodies included in the diagnostic criteria of type 1 autoimmune hepatitis, many other autoantibodies have been described in this condition. Recently, antibodies against cyclic citrullinated peptide have been validated as specific diagnostic and prognostic markers of rheumatoid arthritis.
Aim: To assess whether these antibodies are part of the autoantibody repertoire of type 1 autoimmune hepatitis and correlate with rheumatological manifestations.
Methods: Antibodies against cyclic citrullinated peptide were tested by a commercially available enzyme-linked immunosorbent assay.
Results: The antibodies were found in 12 of 133 (9%) type 1 autoimmune hepatitis, two of 49 (4%) with primary biliary cirrhosis, one of 80 (1%) with hepatitis C virus-related chronic liver disease and 53 of 89 (60%) with rheumatoid arthritis serum samples. High titres were found only in rheumatoid arthritis and type 1 autoimmune hepatitis. No clinical (in particular rheumatological manifestations), biochemical or immunoserological differences were detectable between antibodies against cyclic citrullinated peptide positive and negative type 1 autoimmune hepatitis sera, with the exception of rheumatoid factor, always negative in the positive ones.
Conclusions: Antibodies against cyclic citrullinated peptide can be detected in a subgroup of patients with type 1 autoimmune hepatitis. They might be part of the wide range of autoantibody production characteristic of this condition and/or, less probably, be predictive of future rheumatoid arthritis development.