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 phas es of the menstrual cycle for the number of cell layers and epithelial immu ne cells. STUDY DESIGN: Vaginal biopsies were performed during 3 phases of the normal menstrual cycle (menstrual, days 1-5; preovulatory, days 7-12; and postovu latory, days 19-24) in 74 subjects. A subset of women had vaginal tissues s tained 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 vag inal tissue biopsy specimen were determined by a single observer who was bl inded to clinical data. RESULTS: At 3 phases of the normal menstrual cycle, the mean number of epit helial 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 me an epithelial cell layer count on days 7-12 (23.7 +/- 1.4) compared with th e 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 fiel d of Langerhans cells, macrophages, CD4 or CD8 lymphocytes, and neutrophil cell populations during the 3 phases of the cycle. B lymphocytes were not o bserved in the vaginal tissues. CONCLUSION: A small but statistically significant reduction in the number o f vaginal epithelial cells was observed over the menstrual cycle. This redu ction is not likely to be clinically significant. Immune cell populations i n the vaginal tissues appeared stable throughout the menstrual cycle.