ELISA ASSAY FOR IGG AUTOANTIBODY TO G-ACTIN - COMPARISON OF CHRONIC ACTIVE HEPATITIS AND ACUTE VIRAL-HEPATITIS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 51  (3) , 611-616
Abstract
An ELISA [enzyme-linked immunosorbent assay] was developed to test for human IgG autoantibody to rabbit skeletal muscle G-actin in liver disease. To express results of the ELISA, a single reference serum with known high anti-actin activity was used, and binding of test sera was assessed as a percentage of that displayed by the reference antiserum. Antibody to G-actin was measured in 40 sera from patients with chronic active hepatitis (CAH), 39 from acute viral hepatitis A (Hep A), 46 from acute viral hepatitis B (Hep B), 23 from non-A, non-B hepatitis (Hep non-A, non-B), 31 from systemic lupus erythematosus (SLE), 21 from scleroderma and 93 from normal persons. The results were compared with those obtained using indirect immunofluorescence tests with frozen sections of rodent stomach or fibroblast monolayers as substrates. Anti-G-actin activity of serum was significantly higher (P < 0.001) in CAH (mean 63% .+-. 23, range 18-110) than in controls (mean 15% .+-. 12, range 0-51), systemic lupus erythematosus (mean 25% .+-. 16, range 8-76), scleroderma (mean 23% .+-. 13, range 3-59), Hep A (mean 24% .+-. 11, range 6-25), Hep B (17% .+-. 8, range 2-36), or Hep non-A, non-B (mean 23% .+-. 11, range 7-53). There was no significant difference (P > 0.05) in the occurrence of anti-G-actin activity of serum in Hep A, Hep B or non-A, non-B compared with controls. At an ELISA reading of .gtoreq. 40% (mean + 2 SD of controls) the assay detected autoantibodies to G-actin in 85% of CAH, compared to 80% on fibroblast monolayers and 70% on rodent stomach. The ELISA described is a simple, sensitive and quantitative assay for autoantibody to G-actin. It should prove useful in assessing subspecificities of actin antibodies in liver diseases, and in differential diagnosis, particularly CAH from acute viral hepatitis.