Immunohistochemical properties of the endothelial cells in the human uterus during the menstrual cycle.

Expression of vascular cell adhesion molecule (VCAM) and endothelial leukocyte adhesion molecule (ELAM)-1 on human uterine endothelium was examined by immunohistochemistry. Endomyometrial blocks were obtained from 26 hysterectomy specimens (n = 6, menstrual; n = 6, follicular; n = 14, luteal). VCAM and ELAM-1 expression was compared to that of the classic endothelial markers Factor VIIIRA, CD31, CD34 and CD36, which were found to be present in samples taken from all stages of the cycle. Factor VIIIRA, CD31 and CD34 were expressed on most endothelium whereas CD36 was expressed primarily on that of small vessels. CD36 was also found to be strongly expressed on endometrial epithelium and no changes were apparent during the menstrual cycle. ELAM-1 expression was not detected in any of the tissues examined. VCAM expression varied during the cycle, appearing on endometrial endothelium in the mid- and late luteal phases, stages at which large granular lymphocytes migrate into endometrium. VCAM or a VCAM-like molecule may be involved in migration of large granular lymphocytes into endometrium.