Altered eutopic endometrial T-regulatory and T-helper 17 lymphocyte ratio in women with unexplained subfertility

Perturbations in T-helper lymphocyte profiles have previously been associated with endometriosis related subfertility and conception failure. Hence a retrospective in vitro study was conducted to evaluate the relationship between T-regulatory (Treg) and T-helper 17 (Th17) lymphocytes in the eutopic endometrium of women with unexplained subfertility and correlate these profiles to their conception status.

Eutopic endometrial biopsies were collected during the mid-secretory phase of the menstrual cycle, from women with unexplained subfertility. These samples were evaluated immunohistochemically for Treg and Th17 lymphocytes as well as the related proinflammatory cytokine, Interleukin-17 (IL-17). These eutopic endometrial T lymphocyte subpopulations were compared to the patients' conception status in subsequent cycles.

Though Treg cells were not indicative of conception success in subsequent cycles, patients who maintained their subfertile (no conception) status were observed to have a higher Th17 cell count in their eutopic endometrium. The ratio of Treg:Th17 cell counts was significantly correlated to patient conception status as well. These trends stayed consistent irrespective of concurrent endometriosis.

Patients with a high proinflammatory Th17 lymphocyte profile and low Treg:Th17 ratio in their eutopic endometrium during the secretory phase of their menstrual cycle are more likely to not conceive in subsequent cycles.