The enrichment of Arg1+ILC2s and ILCregs facilitates the progression of endometriosis: A preliminary study.

Innate lymphoid cells (ILCs) are a kind of lymphocytes that reside in the tissue and have an essential function in the immune microenvironment. However, the relationship between endometriosis (EMS) and ILCs is complex and not fully understood. This study examines several groups of ILCs in the peripheral blood (PB), peritoneal fluid (PF) and endometrium of patients with EMS via flow cytometry. The study observed an increase in PB ILCs, particularly ILC2s and ILCregs subsets and Arg1+ILC2s in the EMS patients were highly activated. EMS patients had significantly higher levels of serum interleukin (IL)-10/33/25 compared to controls. We also found an elevation of Arg1+ILC2s in the PF and higher levels of ILC2s and ILCregs in ectopic endometrium compared with eutopic. Importantly, a positive correlation was observed between the enrichment of Arg1+ILC2s and ILCregs in the PB of EMS patients. The findings indicate that the involvement of Arg1+ILC2s and ILCregs fosters potentially endometriosis progression.