Patients with pES show alterations in different immune compartments of T and B cells. (A) Age-normalized percentage of CD4⁺ naïve T-cell population in different patient groups. (B-C) Percentage of HLA-DR⁺CD38⁺ expression on effector memory compartment of CD4⁺ and CD8⁺ T cells in different patient groups. (D) Flow cytometry plots showing expression of CSMB (CD19⁺CD27⁺IgM⁻IgD⁻) on CD19⁺ B cells in HC and patient with pES. (E) Percentage of CSMB in HCs (n = 24), patients with pES (n = 24), and patients with cITP (n = 22). (F-H) Plots showing frequency of cTfh, CD4⁺ T‐cell activation, and CSMB in the longitudinal follow-up of patients with pES (n = 6). Data represent mean ± SEM values for each group. Kruskal-Wallis 1-way ANOVA followed by Dunn’s multiple comparison test for nonnormally distributed samples and ordinary 1-way ANOVA followed by Tukey’s multiple comparison test for normally distributed samples were used for statistical comparison. *P < .05; **P < .01; ***P < .001; ****P < .0001; ns, not significant.