Analysis of expression intensity of NK cell receptor in peritoneal fluid in endometriosis

To clarify the details of peritoneal fluid NK (pfNK) cell involvement in endometriosis, we investigated the expression of anctivating and inhibitory receptors on pfNK cells and cytokine production by pfNK cells in endometriosis. The patients who need surgical treatment for Endometriosis (endometriosis group, n=32) and other gynecological benign disease without endometriosis (controls, n=30) were included for this study. Peritoneal fluid were collected at the time of surgery. The exprssion of pfNK cells (CD56+ cells) were assayed for activating receptors (CD16, NKp46, NKG2C, NKG2D), inhibitory receptors (CD158a, NKG2A), and intra-cellular cytokines (TNF-α, IFN-γ, IL-4, IL-10, TGF-β) by 6 flow cytometry. CD56 dim /NKp46 + NK cells were significantly decreased in endometriosis group compared to controls. (p<0.05). Furthermore, NKG2C + /NKp46 + NK cells were significantly decreased in endometriosis group compared to controls. (p<0.05) On the other hand, NKp46 + /NKG2D + NK cells were significant increased in endometriosis group compared to controls (p<0.05). IFN-γ-producing NK cells in endometriosis group was significantly higher than that in controls (P<0.05). pf NK cells differ in cytotoxicity according to the expression intensity of NKG2C, NKG2D, and NKp46 receptors, which may be related to their abnormal cytokine production. In women with endometriosis, the decrease of cytotoxicity for pf NK cells causes the progression of pelvic endometriosis.