CD19 and acute myeloid leukemia: CD9 expression was observed on monocytes on normal BM and normal peripheral blood, and absence of CD9 expression was observed on granulocytes as previously reported (Figure 1A).23 We analyzed CD9 expression on normal hematogones (HTG) (CD38++ CD19+ CD45 dim), on physiologic myeloblasts gated as CD45dim/SSClow cells after exclusion of hematogones from 25 normal BM and on blast cells from 112 AML patients with the same gating.