Thymoma-specific antibodies in sera from patients with myasthenia gravis demonstrated by indirect haemagglutination.

An indirect haemagglutination technique for the demonstration of antibodies to skeletal muscle is described. Eight out of 9 sera from unoperated myasthenia gravis (MG) patients with thymoma and 6 out of 22 sera taken from MG patients who had been operated upon for a thymoma, contained antibodies to this antigen. Twenty-five sera from MG patients with histologically verified thymus hyperplasia did not contain such antibodies. There was no relationship between these antibodies and antibodies to acetylcholine receptor.