Identification of P‐selectin glycoprotein ligand‐1 as a useful marker in acute myeloid leukaemias

Immunophenotyping is considered to be less valuable in the diagnosis of acute myeloid leukaemias (AML) compared with acute lymphoid leukaemias. Here, we present data on the use of quantitative flow cytometry (QFC) of P‐selectin glycoprotein ligand 1 (PSGL‐1, CD162) and three‐colour immunophenotyping including CD162 staining in the identification of myeloid precursors in AML. Analysis of normal peripheral blood (n = 20) and normal bone marrow (n = 5) samples and on 20 samples from de novo M1, M2, M4 and M5 AML patients demonstrated that PSGL‐1 is differentially expressed on various mature and immature leucocyte subsets. It was found by QFC that neutrophils expressed 26500 ± 4500 and monocytes 47200 ± 9900 copies of PSGL‐1 on their surface, whereas AML blasts from M1 and M2 AML patients expressed significantly less PSGL‐1 (12 000 ± 5300) than mature neutrophils (P