CD19 and myelodysplastic syndrome: The most notable change was the significant reduction of Pre-B/Pro-B cells in both CHIP and MDS compared to Control (Fig. 5A, Supplementary Fig. 2I), consistent with the diminished (mature) B cell signatures seen in our NanoString data and the reduced frequencies of CD10+/CD19+ B cells detected by flow cytometry (Fig. 1E, F, and Supplementary Fig. 1C).