Epithelial cell layer thickness and immune cell populations in the normal human vagina at different stages of the menstrual cycle

OBJECTIVE: The aim of our study was to examine vaginal tissue during 3 phases of the menstrual cycle for the number of cell layers and epithelial immune cells. STUDY DESIGN: Vaginal biopsies were performed during 3 phases of the normal menstrual cycle (menstrual, days 1-5; preovulatory, days 7-12; and postovulatory, days 19-24) in 74 subjects. A subset of women had vaginal tissues stained with specific monoclonal antibody markers for Langerhans cells (CD1a), macrophages (KP1), T and B lymphocytes (CD4, CD8, CD21) and neutrophils (CD15). The number of cell layers and the number of immune cells in the vaginal tissue biopsy specimen were determined by a single observer who was blinded to clinical data. RESULTS: At 3 phases of the normal menstrual cycle, the mean number of epithelial cell layers underwent a small but statistically significant decrease from 27.8 +/- 0.7 on days 1-5 and 28.1 +/- 0.6 on days 7-12 to 26.0 +/- 0.7 on days 19-24 of the cycle (P = .01). Nonovulating women had a reduced mean epithelial cell layer count on days 7-12 (23.7 +/- 1.4) compared with the epithelial cell layer count in ovulating women (28.8 +/- 0.7; P = .005). No significant changes were observed in the mean number per high-power field of Langerhans cells, macrophages, CD4 or CD8 lymphocytes, and neutrophil cell populations during the 3 phases of the cycle. B lymphocytes were not observed in the vaginal tissues. CONCLUSION: A small but statistically significant reduction in the number of vaginal epithelial cells was observed over the menstrual cycle. This reduction is not likely to be clinically significant. Immune cell populations in the vaginal tissues appeared stable throughout the menstrual cycle.