Relationship of immunophenotypic features with minimal residual disease detection and gene types in 221 cases of acute promyelocytic leukemia / 中国实验血液学杂志

ABSTRACT

This study was aimed to investigate the relationship of immunophenotypic features with minimal residual disease (MRD) detection and gene types in APL patients. Immunophenotypes were analyzed in 221 newly diagnosed APL patients by using four-color flow cytometry. Among of them, CD123 antibody was examined in 87 patients and the fused gene pml-raralpha were detected by PCR in 196 specimens simultaneously. The results of immunophenotyping demonstrated that the positive percentages of CD123, CD33 and CD9 in newly diagnosed APL patients were 100%, 99.1% and 96.0% respectively, and mean percentages of positive cells in positive patients were all around 90%. Although the positive rates of CD117, CD13, CD38 and CD64 were all above 96%, but the mean percentages of positive cells in different positive patients were diverse and average percentages of positive cells were about 70%. CD15, CD56 and CD11b were expressed in some patients, but CD34 and HLA-DR were rarely expressed in the majority of patients, and average positive percentages were all lower. Among 196 newly diagnosed APL patients, bcr1, bcr2 and bcr3 expressions were 63.3%, 4.6% and 32.1% respectively. The results showed a strong correlation of positive expression of CD34 with bcr3 isoform. When cut-off value was chosen as 20%, the proportions of CD34 positive patients in bcr3 and bcr1 cases were 15.4% (10/65) and 3.3% (4/121) separately, which had a significant difference (p < 0.05). When cut-off value was 10%, bcr3 cases had a significantly higher percentage of CD34 positive, compared with bcr1 cases (p < 0.001), which was 47.7% (31/65) and 5.8% (7/121) respectively. However, there was no statistically significant difference on the other antigens between the two groups. Bcr3 isoform was highly indicated when CD34 was positive and non- large side scatter (NL-SSC) was shown in APL cells. It is concluded that there is a unique characteristics of immunophenotyping, and antigens such as CD123, CD33 and CD9 are more applicable to the detection of MRD in APL patients. The positive expression of CD34 and NL-SSC are associated with bcr3 isoform, and the relationship between gene type and antigen expression can be suggested more accurately when the cut-off value is chosen as 10%.