Cytokine secretion and expression of transcription factors in WAS. (A) Flow cytometric analysis of IL-21⁺ cells in WAS patients and HCs. (B) Percentage of IL-21⁺ cells within CD4⁺CXCR5⁺ T cells in WAS patients (n = 11; P1-P11) and HCs (n = 15). (C) Gene expression of IL-21 mRNA of CD4⁺ T cells in WAS patients (n = 5; P1, P6-P9) and HCs (n = 6). (D) Gene expression of BCL6 mRNA of CD4⁺ T cells in WAS patients (n = 5) and HCs (n = 6). (E) Gene expression of PRDM1 mRNA of CD4⁺ T cells in WAS patients (n = 5) and HCs (n = 6). (F) Gene expression of IL-21 mRNA of Tfh cells in WAS patients and HCs (n = 6). (G) Gene expression of BCL6 mRNA of Tfh cells in WAS patients and HCs (n = 6). (H) Gene expression of PRDM1 mRNA of Tfh cells in WAS patients and HCs (n = 6).