Figure 4.

Oral contraception alters CD45RA/CCR7 memory phenotype marker expression in CD4⁺ Treg cells. Peripheral blood drawn at early-, mid-, and late-cycle stages from naturally cycling women (N), women using oral contraception (OC), and men was analyzed by flow cytometry to assess CD45RA and CCR7 expression in CD3⁺CD4⁺CD25⁺FOXP3⁺CD127^−/lo Treg cells, allowing classification of cells into naïve (CD45RA⁺CCR7⁺), central memory (CM; CD45RA⁻CCR7⁺), effector memory (EM; CD45RA^-CCR7⁻), or terminally differentiated effector memory (EMRA; CD45RA⁺CCR7⁻) subsets. Panels show the relative proportion of naïve, CM, EM, and EMRA cells among Treg cells (A), the number of naïve cells (B), the number of CM Treg cells (C), the number of EM Treg cells (D), and the number of EMRA Treg cells (E). Data are shown by group as estimated marginal means (A, and left side, bar graphs B-D) calculated by linear mixed model analysis (Model 1, all participants). Individual data points are also shown for each woman at each cycle phase in the N and OC groups (right side, bar graphs B-D), with mean ± SE of the mean indicated. In (A), the effects of participant group were analyzed by Chi-square analysis. In (B) to (D), the effects of participant group, female sex, OC use, and time of cycle were assessed by linear mixed model analysis and pairwise comparisons (n = 10-17 participants/group). ^a,b,cDifferent superscripts indicate differences between participant group (Model 1). ǂSignificant effect of sex (Model 1). ^ϕSignificant effect of cycle stage (Model 2). *Significant effect of OC at specific cycle stages (Model 2). All Ps < 0.05.