Identifying the presence of antibodies against endometrial antigens. A preliminary study

Serum and peritoneal fluid from women with and without evidence of endometriosis were tested for the presence of antibodies against endometrial tissue antigens with Western blot analysis. Serum antibodies against endometrial cytosolic antigens of molecular weight 45, 52, 58, 62 and 66 kd were present in samples obtained from women both with and without endometriosis. The patients with endometriosis had serum antibodies against 34-kd endometrial cytosolic antigen, which was not present in serum from fertile women without endometriosis. The peritoneal fluid from patients with endometriosis also reacted with 34-kd endometrial antigen but not the peritoneal fluid from control fertile women. There was no difference in the antigens detected with serum antibody when endometrium from fertile women without evidence of endometriosis and from women with endometriosis was used as a source of antigen. The presence of serum antibody against 34-kd endometrial antigen is specific to endometriosis. However, this antigen is expressed by endometrium of women both with or without endometriosis. Isolation and identification of this antigen may lead to development of a noninvasive aid for the diagnosis of endometriosis.