Autoimmunity in infertile patients with endometriosis.

General and specific immune function was studied in infertile patients with endometriosis and in controls with proved fertility and absence of pelvic pathology. General nonspecific parameters studied included serum IgG, IgA, IgM, C3, C4, and total complement levels. Immunofluorescence and Ouchterlony immunodiffusion techniques were used to study specific immune function by assaying for endometrial antibodies in serum and peritoneal fluid. Peritoneal fluid volume was also assessed. IgA levels were decreased in infertile patients with endometriosis. IgG, C3, and C4 levels were also decreased in the follicular phase of the menstrual cycle in these patients. The volume of peritoneal fluid was increased in these patients and a significant number of these had low C4 levels. The immunodiffusion studies identified antiendometrial antibodies in the serum and peritoneal fluid in infertile patients with endometriosis. This study has shown that the immune system is altered in infertile patients with endometriosis.