Immunoproteins in the endometrium: clinical correlates of the presence of complement fractions C3 and C4.

The presence of complement fractions C3 and C4 in endometrial tissue was studied in a consecutive series of patients undergoing diagnostic laparoscopy, to determine their specific association with endometriosis. The incidence of complement in eutopic endometrium of patients grouped according to four diagnoses was: endometriosis, 66% positive (23 of 35); active pelvic inflammatory disease, 85% positive (11 of 13); combined endometriosis with pelvic inflammatory disease, 25% positive (one of four); laparoscopically normal pelvis, 67% positive (10 of 15). These differences were not statistically significant. Complement was equally likely to be found in proliferative, secretory, menstrual, or inflammatory endometrium. Endometrial complement was found less frequently in patients with severe endometriosis as compared with those with the mild form. Among patients with endometriosis and infertility, complement was much more likely to be found in patients with primary infertility than in those with secondary infertility (p less than 0.007). In short-term follow-up of these patients, the absence of complement in the eutopic endometrium appeared to be a good predictor of subsequent pregnancies.