Interleukin-17A is present in neutrophils in endometrioma and stimulates the secretion of growth-regulated oncogene–α (Gro-α) from endometrioma stromal cells

Objective: To investigate a new role of interleukin (IL)-17A in endometriosis. Design: Laboratory study. Setting: University hospital. Patient(s): Patients with ovarian endometrioma undergoing laparoscopy or laparotomy. Intervention(s): Primary culture of endometrioma stromal cells (EoSCs) was stimulated with IL-17A. Sections of endometrioma tissue were immunostained with antibodies for IL-17A, growth-regulated oncogene–α (Gro-α), and elastase, a marker of neutrophils. They were also examined with immunofluorescent double staining for IL-17A and myeloperoxidase, another marker of neutrophils. Main Outcome Measure(s): Concentration of Gro-α was measured using a specific ELISA. Neutrophil chemotaxis was measured with Boyden chamber method. Immunostained sections were examined under microscope. Result(s): Interleukin-17A increased the secretion of Gro-α from EoSCs dose-dependently. The conditioned medium of EoSCs stimulated with IL-17A attracted more neutrophils than that of EoSCs stimulated with vehicle, and the increase was inhibited by the addition of Gro-α-neutralizing antibody. On immunostaining, IL-17A and Gro-α were detected in similar areas of the stroma beneath the epithelium, where Gro-α was detected in cells with a stromal cell appearance whereas IL-17A was detected in neutrophils as determined by detection of elastase. Fluorescent immunostaining corroborated that myeloperoxidase-positive neutrophils were also positive for IL-17A. Conclusion(s): It is suggested that IL-17A produced by neutrophils stimulates Gro-α secretion from EoSCs, thereby recruiting more neutrophils and inducing perpetuating inflammation in endometriosis. [ABSTRACT FROM AUTHOR]