Restricted clonality of antithyroglobulin antibodies in an M-component of Hashimoto's serum.

Abstract

In serum of a 70 y. female with Hashimoto's thyroiditis we have identified an M-component IgG which is predominantly composed by a single class of antihuman thyroglobulin antibody. Our assumption is supported by Scatchard analysis and by the high concentration of lambda chains in serum and IgG fraction which are absorbed by h-thyroglobulin. Attempts to dissociate the monoclonal antibody treating the immunoprecipitate at acidic pH, were unsuccessful; only a few percent (3.7) of the antibodies could be released from immunoprecipitate and those were polyclonal. In order to explain the immunoprecipitating reaction of the monoclonal antibody, it is suggested that the antibody is reacting with a repetitive structure of the h-thyroglobulin molecule.