T cell subsets frequencies were then interrogated by PCA: STAT3, XLA, and SIgAD groups did not show any evident alteration (Supplementary Figures S4A,B), with the exception of one SIgAD patient with severe autoimmune cytopenia clustering far from the SIgAD group (A13) and two XLA patients (X2 and X4) with TEM/EMRA CD8+ cell expansion (Supplementary Figure 4B). The gene discussed is CD8A; the disease is selective IgA deficiency disease.