Flow Cytometric Analysis of Leukocytes in the Human Female Reproductive Tract: Comparison of Fallopian Tube, Uterus, Cervix, and Vagina

TLDR

The tissues of the human female reproductive tract may differ in their contributions to mucosal immunity. The study aimed to develop a uniform method for quantitatively comparing leukocytes across the fallopian tube, uterus, cervix, and vagina. Tissue samples (0.5–1.0 g) were enzymatically dispersed and analyzed by three‑color flow cytometry using CD45 positivity and low far‑red autofluorescence to phenotype T cells, B cells, macrophages, and granulocytes. Leukocytes comprised 6–20 % of cells, with the fallopian tube and uterus having higher proportions; T cells dominated (30–60 %) across tissues, while granulocytes were abundant only in the fallopian tube; post‑menopausal uterine endometrium contained fewer leukocytes than pre‑menopausal tissue, confirming that the method can quantitatively compare leukocyte populations and revealing tissue‑specific differences, notably the high granulocyte content of the fallopian tube.

Abstract

PROBLEM: The tissues of the human female reproductive tract (Fallopian tube, uterus, cervix, and vagina) may play different roles in the provision of mucosal immunity. The purpose of this study was to develop a uniform method suitable for quantitative comparison of the leukocytes from all these tissues. METHOD OF STUDY: Tissues, typically 0.5‐1.0 g, were dispersed by enzyme treatment. A flow cytometric gating procedure based on CD45‐positivity and low far‐red autofluorescence permitted unfractionated, freshly dispersed cells to be phenotyped with respect to T lymphocytes, B lymphocytes, macrophages, and granulocytes. RESULTS: Reproductive tract tissues contain leukocytes that represent approximately 6–20% of the total number of cells, with the Fallopian tubes and uterus containing a higher proportion of leukocytes than the cervix and vagina. The uterine endometrium from postmenopausal women has fewer leukocytes than does uterine endometrium from pre‐menopausal women. T lymphocytes are a major constituent (30–60%) of leukocytes from all tissues. The Fallopian tube contains granulocytes as another major constituent; granulocytes are significantly less numerous in the other tissues. All tissues contain B lymphocytes and macrophages as clearly detectable but minor components. CONCLUSIONS: Three‐color flow cytometry is an appropriate method for quantitative comparison of leukocytes from the different tissues of the female reproductive tract, during all phases of the menstrual cycle and within post‐menopausal samples. Results indicate that the tissues differ from each other, particularly with respect to the large number of granulocytes in the Fallopian tubes.