Regulatory T cells and recent thymic emigrants. (A) Peripheral blood flow cytometric analyses, gated on CD4⁺ T cells and analyzed for Tfh-like cells (boxed as CXCR5⁺ CD45RA⁻). (B) Regulatory T cells (boxed CD127^low, CD25^high). Percentage of CD4 T cells within the gated subsets is shown. Histograms show intracellular staining for Foxp3 expression in cells within the CD127^low, CD25^high gate (red histogram) and within the cells excluded from this gate (blue histogram). (C) Frequencies of circulating Tfh-like cells (cTfh) and Tregs (*P = .03; ***P < .0001). (D) Frequencies of CD31⁺ CD4⁺ recent thymic emigrants (E) among CD4 T cells from healthy controls (open circles); healthy sibling (black-filled circles); NFKB2 mutant siblings and parent (black-filled squares). (E) Flow cytometric analysis of peripheral blood mononuclear cells for recent thymic emigrants (CD31⁺ CD4⁺).