HORMONAL-REGULATION OF COMPLEMENT FACTOR-B IN HUMAN ENDOMETRIUM

PROBLEM: Recent investigations have demonstrated the presence of compl ement components in human endometrium in a cycle-specific manner. Lute al phase endometrium has been shown to synthesize complement C3 de nov o. whereas proliferative endometrium produces little or no C3. Likewis e factor B. which is critical to the activation of the alternative pat hway of complement. has been shown to be present only in the glandular epithelium of luteal phase endometrium. This investigation was design ed to determine if factor B is present in the endometrium in a high pr ogesterone state such as pregnancy or with exogenous progesterone trea tment. METHOD: Endometrial biopsies were obtained from patients on pro gesterone therapy. The endometrium of early pregnancy was evaluated by obtaining biopsies from patients with ectopic pregnancies as well as from patients undergoing therapeutic termination. Immunohistochemistry was performed on each biopsy using monoclonal antibodies to factor B. RESULTS: Our results demonstrate the presence of factor B in the glan dular epithelial cells of the endometrium of patients treated with exo genous progesterone therapy. Additionally, factor B was localized to t he glandular compartment of the endometrium from patients with ectopic gestations. Interestingly, the evaluation of an implantation site fro m an early gestation demonstrated factor B in the maternal decidua onl y; trophoblast did not exhibit the presence of factor B. CONCLUSION: F actor B exists in the endometrium in a hormone-dependent manner and is not expressed in fetal tissue in early gestation.