E2A is involved in promoting forkhead box P3 (FOXP3) and retinoid-related orphan receptor gamma t (RORγt) gene transcription,which are pivotal transcription factors of T regulatory cells and Thl7 cells,respectively.Little is known about the involvement of E2A in pregnancy process.This study aimed to investigate the expression of E2A,cytotoxic T-lymphocyte-associated protein 4 (CTLA-4),and Foxp3 in luteal phase endometrium of women suffering recurrent miscarriage (RM) (n=21) and control group (n=11) by immunohistochemistry,with the Vectra(R) automated quantitative pathology imaging system for analysis.The percentage of E2A+ cells and CTLA-4+ cells was significantly higher in the endometrium of women with RM than in the controls.There was positive correlation between E2A and CTLA-4 (r=0.523,P=0.002),E2A and FOXP3 (r=0.380,P=0.032),and FOXP3 and CTLA-4 (r=0.625,P=0.000) in the mid-secretory phase of endometrium for all subjects.It was concluded that the abnormal expression of endometrial E2A existed in mid-secretory endometrium of women with RM,and there was a positive correlation between E2A and FOXP3,and E2A and CTLA-4,suggesting the possible regulation role of E2A involved in regulating endometrium receptivity.