Hepatitis C virus (HCV) causes various extrahepatic immunologic abnormalities. Recently, an association between HCV
infection and
antiphospholipid syndrome, including
thrombocytopenia, has been reported. However, the precise relationship between
thrombocytopenia and
anticardiolipin antibodies in patients with chronic HCV
infection is not fully understood; likewise, the association of
antiphospholipid syndrome and various
liver diseases is not well understood. To evaluate the prevalence and importance of
antiphospholipid antibodies in various chronic
liver diseases, we determined the levels of
anticardiolipin antibodies, platelet numbers, and levels of platelet-associated
immunoglobulin G (PA-
IgG) and
thrombin-antithrombin III complex (TAT) in patients with chronic HCV
infection, chronic hepatitis B virus (HBV)
infection, and
primary biliary cirrhosis (PBC). The prevalence of
anticardiolipin antibodies in patients with HCV
infection was significantly higher than that in control subjects or individuals with the other
liver diseases examined. However, there was no significant correlation between
anticardiolipin antibodies and platelet counts or TAT. The frequency of thrombotic complications was similar in
anticardiolipin antibody-positive and -negative patients with chronic HCV
infection. Further, sera from all but one
anticardiolipin antibody-positive HCV patient were negative for
phospholipid-dependent anti-beta2
glycoprotein I
antibodies. Our results suggest that
anticardiolipin antibodies are frequently found in patients with chronic HCV
infection, but they do not appear to be of clinical importance. Immunologic disturbances induced by HCV or prolonged tissue damage in systemic organs as a result of the extrahepatic manifestations of HCV
infection may induce the production of
antibodies to various
cardiolipin-
binding proteins or
phospholipids.