[Role of Flow Cytometry in the Diagnosis of Chronic Myeloid Leukemia]

To analyze the immunological phenotype of chronic myeloid leukemia (CML), and explore its characteristics and significance.

The immunophenotypes of 40 CML children and 40 controls were analyzed by multicolor flow cytometry. CD45/SSC, as the basic gate, was used to delineate neutrophils. Then, the distribution of cluster differentiation (CD) molecules on the surface of granulocytes was analyzed in three ranges (≥1%, ≥5%, and ≥20%), and the expression rates of CD molecules (≥1% included in the statistical analysis) and the mean fluorescence intensity (MFI) were compared between the two groups.

The proportion of granulocytes in the CML group was (82.1±6.4)%, which was significantly higher than (57.8±11.8)% in the control group (P <0.001). The expression rates of CD15/CD11b/CD33/CD13 in CML and control groups were high, and both distributed in the range of ≥20%. The differentiation trajectory of CD33/CD13 was normal and there were no significant differences in the expression rate and MFI between the two groups. However, both the expression rate of CD11b and CD15 MFI in the CML group were significantly lower than those in the control group (P <0.001). There were no significant differences in the expression rate and MFI of CD10 between the two groups, and the expression levels of CD10 between the two groups were consistent in different distributions. In the CML group, there was a large number of cases with abnormal high expression of CD56, 52.5% of the cases had a CD56 expression rate of ≥5%, and 42.5% had a CD56 expression rate of ≥20%, while the control group did not express CD56 (<1%). The expression distribution of CD117 was different between the two groups. In the range of expression rate ≥5%, there were 35.0% cases in the CML group, while only 2.5% in the control group. The expression rate of CD117 in the CML group was higher than that in the control group (P <0.001), though there was no significant difference in MFI.

The immunophenotyping of CML is characterized by increased proportion of mature neutrophils, decreased CD15 MFI, decreased proportion of CD11b and abnormal high expression of CD56 and CD117. Flow cytometric analysis of immunophenotype can effectively distinguish normal granulocytes from chronic granulocytes, and help in the diagnosis of CML.