Depot medroxyprogesterone acetate increases immune cell numbers and activation markers in human vaginal mucosal tissues

Abstract

The relationship between exogenous contraceptive hormones and permissiveness of the female genital tract to human immunodeficiency virus type 1 (HIV-1) is the subject of renewed debate. To better characterize the effect of depot medroxyprogesterone acetate (DMPA) on HIV-1 cellular targets and epithelial integrity in the vagina, we compared leukocyte populations, markers of activation and proliferation, and the density of intercellular junctional proteins in the vaginal epithelium of women during the follicular and luteal phases of the menstrual cycle and approximately 12 weeks after receiving a DMPA injection. This prospective cohort study involved 15 healthy women. Vaginal biopsies were obtained in the follicular and luteal phases of the menstrual cycle, and approximately 12 weeks following a 150-mg intramuscular injection of DMPA. Leukocyte populations, activation phenotype, and epithelial tight junction and adherens proteins were evaluated by immunohistochemistry. After receiving DMPA, the numbers of CD45, CD3, CD8, CD68, HLA-DR, and CCR5 bearing immune cells were significantly (p<0.05) increased in vaginal tissues, compared to the follicular and/or luteal phases of untreated cycles. There were no significant differences in immune cell populations between the follicular and luteal phases of the control cycle. There were also no statistically significant differences in epithelial thickness and density of epithelial tight junction and adherens proteins among the follicular, luteal, and post-DMPA treatment sampling points. In this pilot study, vaginal immune cell populations were significantly altered by exogenous progesterone, resulting in increased numbers of T cells, macrophages, and HLA-DR- and CCR5-positive cells.

FIG. 1.

Individual changes in vaginal immune cell populations comparing follicular phase and after depot medroxyprogesterone acetate (DMPA) treatment. Total cell density (cells/mm²) for each subject was plotted for the selected immune cell markers. In spite of substantial variability in individual responses, the majority of the samples showed increased numbers of immune cells and activation markers. In some cases, the increase was several fold in magnitude. All cells were quantified in the epithelium, except for CCR5⁺ and CD4⁺ cells, which were detected only in the lamina propria.

FIG. 2.

Vaginal immune cells in follicular, luteal, and post-DMPA treatment. Immunohistochemistry staining of paraffin-embedded tissue blocks of vaginal biopsies taken during the follicular phase (A, D, G, J), luteal phase (B, E, H, K), and 3 months after DMPA injection (C, F, I, L). Vaginal tissues exposed to DMPA showed significantly increased density of CD3⁺ (A, B, C), CD8⁺ (D, E, F), and CCR5⁺ (G, H, I) cells compared to the luteal phase, and greater expression of HLA-DR⁺ (J, K, L) cells compared to the follicular phase. Cell phenotypes were identified using specific monoclonal antibodies against each marker, and cell density was expressed per square millimeter of tissue (cells/mm²).

FIG. 3.

DMPA treatment does not alter epithelial junction protein density. Immunolabeling for the epithelial tight junction protein E-cadherin (A–C) and adherens junction protein ZO-1 (D–F) in vaginal tissue biopsies obtained during the follicular (A, D) and luteal phases (B, E), and following administration of DMPA (C, F). No statistically significant difference in density was observed. Protein expression was calculated using the integrated optical density (IOD) in each area based on positive staining color.