IMMUNOSUPPRESSIVE ACTIVITY OF PERITONEAL-FLUID IN WOMEN WITH ENDOMETRIOSIS

Objective: To investigate the immunosuppressive effect of peritoneal f luid and follicular fluid on both natural killer-mediated cytotoxicity and phytohemagglutinin-induced lymphocyte proliferation. Methods: The peritoneal fluid of women with endometriosis was compared to both fer tile and infertile control fluids. Lymphocytes were pretreated for 2 o r 20 hours with peritoneal or follicular fluids, and their cytotoxicit y toward K562 tumor cells was measured. We also investigated the phyto hemagglutinin-induced stimulation of lymphocytes co-cultured with peri toneal or follicular fluid. Results: Peritoneal fluid from women with endometriosis had a significantly greater immunosuppressive effect on natural killer-mediated cytotoxicity and on phytohemagglutinin stimula tion of lymphocytes compared to peritoneal fluid of fertile women with out endometriosis (P < .01 and P < .05, respectively). Using the perit oneal fluid of infertile women without endometriosis, these difference s were significant only when compared to women with severe endometrios is. Inhibition of the natural killer activity increased when the incub ation period was prolonged from 2 to 20 hours (P < .04). There was no correlation between the immunosuppressive effect of peritoneal fluid a nd the volume of peritoneal fluid, the day of the menstrual period, or estradiol, progesterone, prostaglandin E2, or prostaglandin F2alpha l evels. In peritoneal fluid, the factor responsible for inhibition of n atural killer activity was not removed with charcoal treatment. In fol licular fluid, on the other hand, the inhibition of natural killer act ivity decreased significantly after treatment with charcoal. Conclusio n: Natural killer activity is suppressed by the peritoneal fluid of wo men with severe endometriosis; this may be important in the pathogenes is of endometriosis. The factor responsible for the inhibition of natu ral killer activity in peritoneal fluid is different from that in foll icular fluid.