Dysregulation of the Fas/FasL system in mononuclear cells recovered from peritoneal fluid of women with endometriosis.

In endometriosis, regurgitating endometrial cells fail to undergo apoptosis and implant themselves outside the uterus, particularly in the peritoneum. We studied Fas and FasL behaviour by evaluating the percentages of mFas and mFasL-bearing mononuclear cells from peritoneal fluid, the level of Fas and FasL gene expression at both mRNA and protein levels in the same cells, and the sFas and sFasL values in peritoneal fluid of 80 endometriotic women, at four stages of disease severity. We found no variation in percentage of mFas-bearing mononuclear cells; high and unchanging levels of Fas mRNA and protein, and high and invariable sFas values.