Fig. 6

a Representative flow cytometry data, demonstrating the gating strategy used on PBMC for Treg identification and analysis. FSC-area vs. FSC-height was used for doublet discrimination. A “dump” channel was used to gate out dead cells (LIVE/DEAD fixable viability stain), CD14⁺ monocytes and CD19⁺ B cells, and lymphocytes were subsequently selected by FSC vs. SSC. CD4⁺ T cells were gated on the basis of CD4 vs. CD3 staining, then examined for expression of Ki67 and ICOS. Tregs were identified within the CD4⁺ T cell population as CD25^hiCD127^lo and Foxp3⁺. b Longitudinal empirical data, linear mixed models and estimated means (left, centre and right-hand panels respectively) for Ki67+ and ICOS+ expression on CD4+ T cells, and the Treg proportion of CD4 cells (P-values: * <0.05, ** <0.01, *** <0.001, **** < 0.0001)