Despite the low percentage of IMCs identified as CD11b+CD33+CD14-HLADR-CD34+ cells, CML Gr-MDSCs are more immature cells compared to autologous PMNs, and showed lower levels of expression of CD11b, CD15, and CD16, and lower Arg1 expression and activity (6). This evidence concerns the gene ARG1 and chronic myelogenous leukemia, BCR-ABL1 positive.