Evidence for the presence of follicle-stimulating hormone receptor antibody in human serum.

A male patient presented with polyostotic fibrous dysplasia, elevated serum gonadotropin levels, primary gonadal failure, and an immunoglobulin M (IgM) monoclonal gammopathy. When the patient's serum was added to radioiodinated human follicle-stimulating hormone (125I-hFSH)-bovine testis membrane-receptor complex solubilized by detergent, followed by the addition of antihuman immunoglobulin G ((anti-hIgG), the preformed complex was precipitated. No such precipitation was seen when normal human or rabbit serum, serum from a patient with polyostotic fibrous dysplasia, or serum from other patients with polyclonal gammopathies were utilized. The patient's serum did not precipitate free 125I-hFSH. Detergent-solubilized testis receptor not complexed to hFSH, as well as highly purified radioiodinated receptor were also precipitated when this serum was added followed by anti-hIgG. Our results indicate that serum from the patient contained antibodies to FSH testis receptor. It is possible that antibodies to gonadal receptors may exist in other patients, although it is not yet possible to assume a causal relationship between the presence of receptor antibodies and gonadal failure.