Effect of peritoneal fluid in women with endometriosis on natural killer cell activity and its relationship with prostaglandins and interleukin-6

Objective To investigate the effect of the peritoneal fluid (PF) in women with endometriosis (EM) on the natural killer (NK) cell activity and its relantionship with prostaglandins(PGs) and interleukin-6(IL-6). Methods The LDH releasing assay was used for measurement of the change of NK cell activity after preincubation with PF of EM. The concentration of IL-6, PGE 2and PGF 2α were measured by radioimmunoassay. Results After incubated with PF of women with and without EM for two hours, the inhibition rate of NK cell activity decreased by 37.1%(18.9% and 65.2%(21.8% respectively.The difference was significant statistically (P0.01). The inhibition rate was correlated with the severity of EM(r=0.6025, P0.05). On prolonation of the incubation duration, the NK cell activity decreased more significantly. The concentration of IL-6 of PF in women with mild EM was significantly higher than women without EM. The concentration of PGE 2and PGF 2α also increased significantly in women with endometrosis, which were correlated with the suppressive effect of NK activity in women with stage Ⅰ and Ⅱ EM. Conclusion PF of EM can significantly decrease NK cell activity in vitro, the suppressive effect of the NK activity is correlated with the concentration of IL-6 of PF in women with stage Ⅰ and Ⅱ EM.