Radioimmunoassay of IgG and IgM anti-albumin autoantibodies in human serum

An antigen-coated plate radioimmunoassay used to detect autoantibodies of IgG and IgM classes against human serum albumin is described. It comprises 3 steps: (a) adsorption of glutaraldehyde-polymerized human serum albumin on the wells of a plastic plate, (b) incubation of the serum to be tested with the antigen in the wells, and (c) the addition of radiolabelled antibodies against human IgG or IgM. The method has been used to estimate the level of anti-albumin autoantibodies (AAA) belonging to IgG or IgM classes in the sera of normal subjects and patients with liver diseases.