Autoantibodies in patients with chronic hepatitis C virus infection: pitfalls for the diagnosis of rheumatic diseases.

Hepatitis C virus infection (HCV) is one of the best mimes in medicine. About 40-70% of patients suffering from this disorder develop at least one extra-hepatic disorder that can have a rheumatic nature (arthralgias, arthritis, vasculitis and sicca syndrome) and must be differentiated from the primitive rheumatic diseases. In addition, HCV infection can also alter the laboratory tests. Several alterations of first line laboratory tests can be usually found in both chronic HCV infection and chronic inflammatory rheumatic disorders. In the present review we analyze the interference of HCV in tests more specifically used in rheumatology: rheumatoid factor and other autoantibodies (ANA, anti-ENA, ANCA, anti-DNA, antiphospholipid, anti-CCP). In patients suffering from HCV infection, the diagnosis of connective tissue diseases (CTD) or rheumatoid arthritis (RA) should be made only when the detected symptoms or laboratory data are not inducible by HCV, otherwise only a diagnosis of "possible CTD" or "possible RA" should be considered.