Autoimmunity. (A) Percentage of VH4-34–expressing B cells before (data includes other patients with WAS who did not undergo GT, data not available for patient 5) and after GT; showing flow cytometry example from a representative patient (patient 4). Statistics performed between HCs and pre-GT groups: Mann-Whitney U test. (B) Evolution of CD21^loCD38^lo B cells (%) after GT. (C) Evolution of Tregs (CD4⁺CD25^hiCD127^lo; left: percentage; right: absolute values) after GT; arrows represent onset of autoimmunity flares. (D) Treg (CD4⁺CD25^hiCD127^loFOXP3⁺) WASp expression (percentage WASp⁺ cells) after GT (2 years after GT). (E) Evolution of transitional B cells (left: percentage; right: absolute values) after GT. (F) Percentage of IL-10–producing B cells (Bregs) in various B-cell subsets in HCs, including transitional (CD19⁺CD24^hiCD38^hi), MZ-like (CD19⁺CD24⁺CD38⁻), and mature (CD19⁺CD24^intCD38^int) B cells. Statistics: Wilcoxon signed-rank test. (G) Percentage of Bregs in patients before and after GT (2 and 5 years after GT) with either absence (AI⁻) or presence (AI⁺) of after GT autoimmunity; showing flow cytometry example from a representative patient (patient 2). (H) Comparative levels of Bregs (left: percentage; right: absolute values) in patients with (AI⁺) and without (AI⁻) post-GT autoimmunity. Graphs represent median with interquartile range. Statistics: Mann-Whitney U test. (I) Percentage of Bregs within transitional B cells in patients before and after GT (2 and 5 years after GT). ∗P ≤ .05, ∗∗P ≤ .01, ∗∗∗P ≤ .001. MFI, mean fluorescence intensity.