Interleukin-15 and Interleukin-7 are the Major Cytokines to Maintain Endometriosis.

The objective of this study was to evaluate cytokines related to natural killer and T-regulatory cells in endometriotic lesions, peritoneal fluid (PF) and the peripheral blood (PB) of patients with deep infiltrative endometriosis. A case-control study was conducted in a tertiary referral hospital. Sixty-four consecutive patients after laparoscopy were divided into 2 groups: with endometriosis (Group A - n = 32) and without endometriosis (Group B - n = 32). Interleukin (IL)-2, IL-4, IL-7, IL-10, IL-12, IL-15, transforming growth factor β1, and IFNγ concentration was measured using a LuminexTM multiplex suspension bead array. Tissues from endometriotic lesions of patients with endometriosis and from eutopic endometrium were evaluated, as well as PF and PB of all patients. Compared to the other analyzed groups, IL-15 concentration was significantly higher in the ectopic endometrium and IL-7 in the eutopic endometrium of the endometriosis group (p < 0.05). Compared to endometriosis group, IFNγ, IL-7, and IL-15 were observed to be significantly higher in the PF of the control group, and IL-10 was lower in the control group (p < 0.05). In PB, compared to endometriosis group, IL-4, IL-10, IL-12, IL-15, and IFNγ concentrations were significantly higher in the control group (p < 0.05). Our hypothesis is that deep endometriosis is a disease out of control. This disease's nature is of progression and invasion of adjacent structures, and proof of this disease state is the disorganized secretion of cytokine regulation and inflammation, which seem to be among the factors responsible for the maintenance of the disease.