In patients from Group 1, the number of CD-138 + plasma cells was significantly increased; histological examination showed diffuse plasmacytic infiltration of the endometrial stroma, severe periglandular sclerosis of the stroma, and monomorphic type of glands, which is an immune-histomorphological confirmation of chronic endometritis with reactive endometrial hyperplasia. The gene discussed is SDC1; the disease is chronic endometritis.