Increased Natural Killer Cell Activities in Patients Treated with Gonadotropin Releasing Hormone Agonist

Abstract

Natural killer (NK) cell activity in patients treated with gonadotropin-releasing hormone agonists (GnRH-a) was studied. The subjects were 8 patients with endometriosis (6 with ovarian endometrial cyst, 2 with adenomyosis) and 3 patients with uterine leiomyoma. Changes in serum estradiol (E<sub>2</sub>) concentration and NK cell activity in peripheral blood were analyzed before and after GnRH-a treatment (buserelin 900 μg/day for 4–5 months). NK cell activity was determined by <sup>51</sup>Cr release assay and E<sub>2</sub> by radioimmunoassay. NK cell activity before GnRH-a treatment was 37.7 ± 19.0%, and after therapy activity increased significantly to 50.8 ± 18.2%. However, no significant correlation between the increase in NK cell activity and the decrease in E<sub>2</sub> concentration was found. Results indicate that the standard GnRH-a treatment for endometriosis and uterine leiomyoma might increase NK cell activity. The etiology of the increase of NK activity with GnRH-a treatment is likely related to factors other than E<sub>2</sub> concentration.