CLL cells convert to myeloid lineage in vivo. (A) Representative FACS plots of donor cells on day 4.5 posttransplantation (n = 15). (B) Percentages of donor peripheral blood engraftment and different subpopulations (n = 15). Donor CLL cells are from 4 deidentified CLL patients. Each circle represents an individual mouse. (C) Representative BIOMED-2 genomic PCR for detection of IgH gene rearrangements in FACS-sorted pretransplanted CLL cells and posttransplanted subpopulations. The detection of positive peaks was expected between the regions of 250 to 295 bp and 310 to 360 bp. Note that the same IgH gene rearrangements were detected in the pretransplanted CLL cells (CD45⁺CD19⁺CD20^dim) and posttransplanted donor-derived immature cells (CD45⁺CD19⁻CD11b⁻) and myeloid cells (CD45⁺CD19⁻CD11b⁺) cells (n = 2). (D) Twelve distinct clusters were detected in CLL samples by single-cell RNA sequencing. Note the coexpression of Notch1/2 and Map3k14/NIK with lower expression of BACH2 in cluster 7 (dashed rectangle). BMT, bone marrow transplantation; h, human; m, mouse; PBL, peripheral blood leukocytes.