[Analysis of peripheral blood monocyte subsets in chronic myelomonocytic leukemia: a single-center study].

Objective

To evaluate the clinical value of peripheral blood monocyte subset analysis in the diagnosis and treatment of chronic myelomonocytic leukemia (CMML) . Method: We retrospectively enrolled 51 patients newly diagnosed with CMML at Guangdong Provincial People's Hospital between June 1, 2020, and December 31, 2024, according to the WHO 2022 diagnostic criteria. Twenty-three patients with other myeloid neoplasms (excluding CMML) and peripheral monocytosis (absolute count ≥0.5×10(9)/L and percentage ≥10%) were included as the control group. All patients underwent bone marrow aspiration for examinations including bone marrow smears, biopsies, cytogenetics, and gene mutation analysis to establish a definitive diagnosis. Concurrently, flow cytometry was used to determine the proportions of peripheral blood monocyte subsets: classical (MO1, CD14(+)CD16(-)) , intermediate (MO2, CD14(+)CD16(+)) , and non-classical (MO3, CD14(low)CD16(+)) . Differences between the groups were compared, and diagnostic efficacy was evaluated using receiver operating characteristic (ROC) curves. Result: Among the 51 CMML patients, the proportion of the peripheral blood MO1 subset was significantly higher than that in patients with other myeloid neoplasms (P=0.027) , whereas there were no significant differences in the MO2 and MO3 subsets (all P>0.05) . Further analysis revealed that 43 (84.31%) of the CMML patients met the WHO diagnostic threshold for the MO1 subset (≥94%) , while the remaining 8 patients did not; 46 patients (90.20%) had MO3 subset proportions below the threshold proposed by Hudson (≤1.13%) , while the remaining 5 patients were above this threshold. In-depth analysis showed that among the 8 patients who did not meet the WHO criteria, 7 were experiencing inflammation. Similarly, all 5 patients who did not meet the Hudson criteria were in an inflammatory state. Subsequent ROC curve analysis of this cohort identified a cut-off value for the MO1 subset of 97.55% [Area Under the Curve (AUC) =0.661, P=0.027], which aligns with the WHO criteria.

Conclusion

Peripheral blood monocyte subset analysis, particularly MO1 subset analysis, can effectively assist in CMML diagnosis, but exclusion of inflammatory conditions is required.