Human triclonal anti-IgG gammopathy. I. Iso-electric focusing characteristics of the IgG, IgA and IgM anti-IgG and their heavy and light chains.

Human IgG, IgA and IgM anti-IgG autoantibodies have been isolated from the serum of an individual with Felty's syndrome. These were initially noted as soluble circulating serum complexes by analytical ultracentrifugation. Isolation was accomplished by solid phase immunoadsorption and each of the three antibody populations obtained was shown to be of restricted heterogeneity by liquid and polyacrylamide gel electrofocussing methods. Type kappa light chains were obtained from each protein. Co-isoelectric focusing experiments of all possible pairs of these light chains showed them to have identical net charge characteristics. Heavy chains obtained from each protein were also monoclonal and of differing isoelectric point. The availability of this serum provides a human model with which to study the changes which may occur in autoantibodies during the autoimmune response.