To determine if a clinically applicable flow cytometry methodology could identify chronic myelomonocytic leukemia (CMML) cases.
Monocyte subset screening (CD14/CD16 expression) was performed on 68 blood and 25 bone marrow specimens with a monocytosis and/or flagged as possible CMML. Fifty thousand total events were obtained per case. Cases were categorized as CMML, atypical chronic myeloid leukemia (aCML), or non-CMML + non-aCML by clinicopathologic diagnosis.
The methodology differentiated blood and bone marrow CMML cases from non-CMML + non-aCML but not three aCML cases in the clinical setting. Furthermore, a decreased percentage of nonclassical monocytes (CD14dimCD16+) showed better sensitivity than the previously described approach that relied on increased percentage of classical monocytes (CD14brightCD16-).
Quantification of monocyte subsets is useful in clinical practice as a diagnostic marker of CMML in blood and bone marrow specimens. The percentage of nonclassical monocytes should be included in analysis of monocyte subsets.