MDS patients have a significant increase in MDSCs that negatively correlates with lymphocyte populations. (A) PBMCs from normal donors and MDS patients were stained with anti-CD45, anti-CD33, anti-CD11b, anti-CD14, and anti-HLA-DR mAbs and the percent of MDSCs (phenotypically defined as CD33⁺/CD11b⁺/CD14⁻/HLA-DR^lo/−) of the all-cell fraction was evaluated (****P < .0001). (B-D) Based on the all-cell fraction, the correlation between percent MDSCs and percent CD7⁺ lymphocytes, percent T cells, percent NKT cells, and percent NK cells among all MDS patients (B), lower-risk MDS patients (C), and higher-risk MDS patients (D) is shown. Correlation coefficients (r) and statistical significance are indicated in the figure.