Anti-actin antibodies of IgM and IgG class in chronic liver diseases detected by fluorometric immunoassay.

Using a sensitive fluoroimmunoassay, anti-actin antibodies (AA) of the IgM and IgG classes were measured in 240 patients with various chronic liver diseases and in 211 patients with non-hepatic autoimmune muscle, heart, malignant and inflammatory bowel diseases. Thirty-two out of 40 patients (80%) with autoimmune chronic active hepatitis (CAH) had AA only of the IgG class (geom. mean X = 1.78, SEM +/- 0.07) and only three patients (8%) had both IgG and IgM AA, the latter in lower titres. In patients with primary biliary cirrhosis (PBC) and AMA-positive cholestatic CAH, AA of both IgM and IgG classes were equally represented (60% IgG and 64% IgM AA in PBC, 73% IgG and 51% IgM AA in cholestatic CAH) but the titres were very low (geom. mean IgG AA in PBC 1.035, SEM +/- 0.03, in cholestatic CAH 1.18, SEM +/- 0.02). In contrast to autoimmune (lupoid) CAH, AA were rare in HBsAg positive CAH (9/43, 21%) and only present in low titres. However, in six out of 21 patients with anti-HBs and anti-HBc-positive chronic active hepatitis, high AA of IgG class were found, suggesting the autoimmune type of liver disease. In NANB virus-induced chronic liver disease after blood transfusion, AA were only occasionally found (IgG antibodies 1/19, IgM antibodies 3/19) and none were found in the eight patients with sporadic NANB hepatitis. They were also rare in 30 patients with alcoholic liver disease (3/30, 10%).(ABSTRACT TRUNCATED AT 250 WORDS)