T cell phenotype in non-transplanted patients with heterozygous ITPR3 variants. (A) Distribution of maturation-associated T cell subsets in patients (P2, P4, and P5) versus three pediatric HDs displayed as (I) UMAP projections in concatenated HD (left) and patient (right) samples and (II) stacked bar charts for CD4⁺ (left) and CD8⁺ T cells (right); HD data has been combined and mean and standard deviation (error bars) are plotted. Statistical significance is displayed in the chart in the center of the figure; *P < 0.05, Mann–Whitney U test, across three independent experiments. Maturation-associated subsets are colored according to phenotype and include naïve (TN: CD45RA⁺CD27⁺CCR7⁺CD95⁻; blue), stem central memory (TSCM: CD45RA⁺CD27⁺CCR7⁺CD95⁺; red), central memory (TCM: CD45RA⁻CD27⁺CCR7⁺CD95⁺; grey), transitional memory (TM: CD45RA⁻CD27⁺CCR7⁻CD95⁺; dark green), effector memory (TEM: CD45RA⁻ CD27⁻CCR7⁻CD95⁺; lilac), and terminally differentiated (TD: CD45RA⁺CD27⁻CCR7⁻CD95⁺; orange) CD4⁺ and CD8⁺ T cells, as well as effector CD27^dim (CD45RA⁺CD27^dimCCR7⁻CD95⁺; light green) CD8⁺ T cells. (B) Bar chart showing the percentage of CD31⁺ RTEs within naïve CD4⁺ T cells in patients versus pediatric HDs. (C) Bar chart (right) showing the percentage of PD-1⁺ cells in CD4⁺ and CD8⁺ T cells in patients versus pediatric HDs; representative histograms (left) are shown for P5 and one HD. (D) Bar chart (right) showing the percentage of CD8⁺ T cells positive for (I) granzyme B and (II) perforin in patients versus pediatric HDs. Representative histograms (left) are shown for P2 and one HD. (E) Representative TCRVβ spectratyping shown for P4 on isolated CD3⁺ T cells. All Vβ families are represented; all but one (TRBV30) have a skewed and sparse profile with oligoclonal expansions present and a median number of seven peaks. (F) Bar chart showing absolute numbers of Tregs in patients versus pediatric HDs. (G) Bar chart (right) showing the percentage of iNKT cells within T cells in patients versus pediatric HDs. Representative flow cytometry plots (left) for P5 and one HD are displayed. (H) Representative flow cytometry plots for P2 and one HD showing the percentage of TCR γδ⁺ and ⍺β⁺ cells with total CD3⁺ T cells. For B–D and F–G, representative of three independent experiments, bars represent the median values and lines and the interquartile range. *P < 0.05, Mann–Whitney U test. All statistics were performed using bilateral t tests. n/a, not available.