The detection of CD14 and CD16 in paraffin-embedded bone marrow biopsies is useful for the diagnosis of chronic myelomonocytic leukemia.

Histopathological study of bone marrow biopsy (BMB) in chronic myelomonocytic leukemia (CMML) is often difficult and might benefit from an immunohistochemical approach. We immunostained 15 cases of CMML, focusing at two new antibodies staining for CD14 and CD16 on paraffin-embedded tissues. CD68 (KP1), CD68 (PG-M1), and CD163 were not differentially expressed between CMML and chronic myelogenous leukemia (CML). In CMML BMB, we found a significant increase in the number of CD14+ monocytes. This increase was made of dispersed cells in the interstitium, often exhibiting bilobated nuclei, and being difficult to differentiate from neutrophils. There was no expansion of CD16+ monocyte-like cells. However, we found a significant decrease in the number of granulocytes expressing CD16, MPO, and CD15 in CMML compared to CML and control BMB, probably related to dysgranulopoiesis. Indeed, BMB immunohistochemistry can be helpful in CMML by identifying both the monocyte expansion with CD14 and the dysgranulopoiesis with CD16.