QUANTITATIVE-ANALYSIS OF T-LYMPHOCYTE SUBSETS IN PREGNANT AND NONPREGNANT HUMAN ENDOMETRIUM

The purpose of this study was to characterize and quantify T lymphocyt e populations and to investigate T cell antigen receptor (TcR) express ion in human endometrium throughout the menstrual cycle and in early p regnancy. Frozen sections of endometrium were labeled using the highly sensitive avidin-biotin method and a panel of monoclonal antibodies. CD3-positive, CD8-positive, CD4-positive, TcR alpha beta-positive, and TcR gamma delta-positive cells were demonstrated in all phases of the menstrual cycle and in early pregnancy. There were no differences bet ween pregnant and nonpregnant human endometrium in the proportion that each T cell subpopulation formed relative to the total CD3-positive T cell population. However, significantly fewer T cells were detected i n early pregnant compared with nonpregnant endometrium. Our results cl arify the TcR expression by T cells in pregnant and nonpregnant human endometrium and indicate that endometrial T cells are unlikely to play a significant role in implantation and the maintenance of human pregn ancy since they decrease in number considerably in the first trimester of gestation.