Altered maturation and function of peritoneal macrophages: possible role in pathogenesis of endometriosis.

Human peritoneal macrophages from healthy women and patients with endometriosis were analyzed with flow cytometry for size distribution, cell membrane antigen expression, and membrane function. Endometriosis was associated with a significantly increased number of peritoneal macrophages and a higher proportion of large macrophages with increased expression of three antigen markers. Peritoneal macrophages from normal patients exhibited diminished cell membrane capping function as compared with that of endometriosis-related macrophages or blood monocytes. On the basis of these findings, a hypothesis is formulated suggesting that endometriosis is associated with an increased influx of macrophages that are allowed to undergo further maturation-activation. The resultant population of large macrophages may contribute to the maintenance of the disease or associated infertility.