Deciphering transcriptome alterations in bone marrow hematopoiesis at single-cell resolution in immune thrombocytopenia

Purpose and Methods: Immune thrombocytopenia (ITP), an autoimmune disorder, is mainly caused by megakaryocyte dysfunction, although the underlying mechanisms remain unclear. Here, we performed single-cell transcriptome profiling of bone marrow (BM) CD34+ hematopoietic stem and progenitor cells (HSPCs) to determine defects in megakaryopoiesis in ITP. Results: Gene expression, cell-cell interactions, and transcriptional regulatory networks varied in HSPCs of ITP, particularly in natural killer/T cell progenitors and a pre-B cell subset, highlighting the selective immune aberratixon associated with defective megakaryopoiesis in ITP. CD9 can be used to enrich megakaryocyte-biased HSPCs, and CD9+Lin-CD34+CD45RA- HSPCs have the potential to be novel diagnostic and therapeutic targets in ITP. Further analysis revealed that megakaryocytic progenitors (MkP) can be divided into seven subclusters with different gene expression patterns and functions. The ITP-associated DEGs were MkP subtype-specific, with most DEGs concentrated in the subcluster possessing dual functions of immunomodulation and platelet generation. Conclusions: This study comprehensively dissects defective hematopoiesis and provides novel therapeutic targets for ITP. Overall design: We performed scRNA-seq of BM CD34+ HSPCs from four newly diagnosed treatment-naïve ITP patients and four healthy donors on the 10X Chromium platform to determine the megakaryopoiesis defects in ITP.