[Autoantibody to luteinizing hormone in patient with systemic lupus erythematosus (author's transl)]

One hundred microgram of luteinizing hormone releasing hormone was intravenously injected into 19 female patients with systemic lupus erythematosus and plasma luteinizing hormone levels before and after the injection were determined with a method of solid phase radioimmunoassay. In 4 patients among them, the basal levels of luteinizing hormone were abnormaly high. A question about the existence of autoantibodies to luteinizing hormone in the patient's plasma raised to explain the reason for the high level of luteinizing hormone. The results from 3 experiments for solution of this question were as follows. 1) The patient's plasma was proved to have a binding activity with labeled luteinizing hormone. 2) This binding activity is specifically inhibited by purified luteinizing hormone. 3) This binding activity was located in gamma-globulin fraction. From the results, the existence of autoantibodies to luteinizing hormone in the 2 patients' plasma was concluded.