IMMUNOLOCALIZATION OF THE APOPTOSIS REGULATING PROTEINS BCL-2 AND BAXIN HUMAN ENDOMETRIUM AND ISOLATED PERITONEAL-FLUID MACROPHAGES IN ENDOMETRIOSIS

Endometriosis, a debilitating disease associated with infertility, is characterized by the prolonged presence of ectopic endometrial tissue and the involvement of activated peritoneal fluid macrophages. Apoptos is, which occurs in both endometrium and peritoneal fluid macrophages, is controlled in part by members of the Bcl-2/Bax family of proteins. Here, through immunohistochemical staining, we investigated the Bcl-2 /Bax status in endometrium and peritoneal fluid macrophages in endomet riosis. Bcl-2/Bax immunoreactivity was found predominately in the glan dular epithelial cells, mainly during the proliferative phase of the m enstrual cycle for Bcl-2 but throughout the entire menstrual cycle for Bar. Ectopic endometrium contained a population of Bcl-2 positive, Ba x negative tissue macrophages. Fluorescence-activated cell sorting of isolated peritoneal fluid macrophages showed that women with endometri osis had a significantly higher proportion of Bcl-2 positive macrophag es than the non-endometriotic group. The proportion of Bax positive pe ritoneal fluid macrophages was significantly elevated in women without endometriosis. The increased proportion of Bcl-2 positive macrophages found in women with endometriosis may predispose these cells to resis t apoptosis. The continued survival of these active cells could have i mportant consequences for the survival and proliferation of the ectopi c endometrial tissue.