Fig. 3: Low-dose IL-2 treatment inhibits the differentiation of IL-21-producing CD4⁺ T cells.

a Expression levels of 30 differentially expressed markers in the four assessed IL-21-producing CD4⁺ T cell subsets from in vitro stimulated CD4⁺ T cells: CXCR5⁺ T_CM and CXCR5^lowIL-21⁺ sorted from the CD25^–/low Tconv gate; and CD25⁺ T_FH and CD25⁺IL-21⁺ T_FH sorted from the CD127^lowCD25^hi Treg gate. b Expression of CXCR5 (AbSeq) and IL21 in the four assessed IL-21⁺ CD4⁺ T cell subsets. c, d UMAP plots depicting the clustering of in vitro stimulated CD4⁺ T cells (n = 209,543 cells). Cells are coloured according to the respective IL-21⁺ cluster assignment (c); or by normalised and scaled IL-21 expression levels (d). Dark and light grey denote cells sorted from the CD127^lowCD25^hi Treg gate and CD25^–/low Tconv gate, respectively, that are not in IL-21⁺ clusters. e Gene expression changes between IL-21⁺ and IL-21^– cells within each of the four assessed IL-21⁺ CD4⁺ T cell clusters. Genes with absolute log₂ fold change >= 1.2 and FDR-adjusted P values <0.01 in at least one cluster were selected. Fold change and P values were calculated using a generalized linear model implemented in DESeq2 (see “Methods”). f Relative frequency changes of IL-21⁺ cells within the two CD4⁺ T cell subsets displaying higher expression levels of IL-21: the CXCR5^lowIL-21⁺ subset (left panel) and the CD25⁺IL-21⁺ T_FH subset (right panel), comparing Day 27 and Day 55 with Day 0, respectively. Each dot represents cells from a single participant. Dots with the same colour represent the same participant. n = 13 participants. Each box ranges from the first quartile (Q1) to the third quartile (Q3), with a central line indicating the median. The bottom and top whiskers extend to the most extreme data points within Q1−1.5 × (Q3 − Q1) and Q3 + 1.5 × (Q3 − Q1), respectively. P values were calculated by comparing the relative frequency values between the two time points using a two-sided Wilcoxon signed-rank test. Source data for (a, e, f) are provided as a Source Data file.