Healthy and diseased cells displayed distinct phenotype and signaling signatures. (A) PBMCs from 3 patients with PV and 3 HCs, untreated or treated with 500 U/mL IFN-α, were cultivated in CFU assays for 10 days. The cells were detached and used for scRNA-seq. The uniform manifold approximation and projection for dimension reduction (UMAP) is shown, which depicts the different cell types identified. (B) The relative amounts of different cell types per sample were analyzed. The distribution of cells in untreated HC and untreated PV samples is shown. None of the comparisons reached significance. Left: erythrocytic vs immune associated cells. Middle: different maturation stages of erythrocytic cells. Right: lymphocytic vs myeloid cells. (C) Genotyping of transcripts using locus-specific amplification of the JAK2V617F locus in the scRNA-seq samples. Mutated (hom), het, and WT cells are highlighted in the UMAP plot. (D) Comparison of mutant VAF as calculated from scRNAseq data with next-generation sequencing VAF from peripheral blood from the same patients (E) Comparison of the activity in the indicated pathways. All pathways were previously shown to be differentially expressed in JAK2V617F vs JAK2WT vs HC cells. (F) Integration of the scRNA-seq data in an additional differentiation trajectory model.⁴⁴ Left: location of the analyzed samples in the metacell model. Right: statistical analysis of the differences in cell types. ns, not significant, ∗P < .05; ∗∗ P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001.