Multiparameter profiling of the peripheral blood for patients with ITP before TPO-RA discontinuation. (A) Uniform manifold approximation and projection (UMAP) and clustering of 45 548 single cells from 8 patients at baseline (n = 4 with SCROT and n = 4 with NSR) based on scRNA-seq results. Cell type labels were assigned to clusters based on a manually curated list of marker genes. (B) Relative cluster distribution of all cells from SCROT and NSR donor groups. Bar indicates median. (C-D) Number of CD19⁺ B cells and CD19⁺CD27⁺IgD⁻CD38⁻ memory B cells (MBCs) assessed via flow cytometry at baseline for patients with SCROT, SROT, and NSR. (E-F) Percentages of CD27⁺CD38^int/+CD71⁺ activated B cells (ABCs) and CD27^highCD38^high antibody–secreting cells (ASCs) assessed via flow cytometry at baseline for patients with SCROT, SROT, and NSR. (G) Optical densities (ODs) of anti-GPIIbIIIa antibodies (Abs) measured using specific immobilization of platelet antigen assay at baseline for patients with SCROT, SROT, and NSR. (H-K) Percentages of CD3⁺CD4⁺CCR7⁻CD45RA⁻ memory (T_EM), CD3⁺CD4⁺CCR7⁺CD45RA⁻ central memory (T_CM), CD3⁺CD4⁺CXCR5⁺ICOS⁺PD-1⁺ circulating T-follicular helper (cTFH), and CD3⁺CD4⁺CD25^highCD127^low Treg CD4⁺ at baseline for patients with SCROT, SROT, and NSR. (L) Frequency of GPIIbIIIa-specific CD4⁺ T cells assessed via flow cytometry, with an adapted antigen-reactive T-cell enrichment technology at baseline for patients with SCROT (platelet count >100 × 10⁹/L, SROT [platelet count 30 × 10⁹/L to 100 × 10⁹/L], and NSR [platelet count <30 × 10⁹/L and or bleeding]). Bars indicate median. Kruskal-Wallis and Wilcoxon-Mann-Whitney tests were used as appropriate. Mono, monocyte; NK, natural killer; pDCs, plasmacytoid dendritic cells; RBCs, red blood cells.