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Published on: March 26, 2018
Prognostic value of immunophenotypic characteristics of blast cells in acute myeloid leukemia
F Lanza1, G M Rigolin, S Moretti
1Institute of Hematology, University of Ferrara, Italy.
Insights
Flow cytometry immunophenotyping identified specific leukemic cell characteristics in acute myeloid leukemia (AML) that predict patient prognosis. Co-expression of CD34 and CD33 on blasts is a key independent predictor of shorter survival.
Area of Science:
- Hematology
- Immunology
- Oncology
Background:
- Acute myeloid leukemia (AML) prognosis is influenced by various factors.
- Immunophenotypic analysis of leukemic cells offers insights into AML biology.
- The prognostic significance of CD34 expression in AML requires further clarification.
Purpose of the Study:
- To elucidate the prognostic role of cytofluorimetry analysis of leukemic cells in AML.
- To investigate the association between immunophenotypic characteristics and patient survival.
- To identify specific markers predicting prognosis in AML patients.
Main Methods:
- Flow cytometry was used to analyze immunophenotypic characteristics of blast cells from 66 AML patients.
- A comprehensive panel of monoclonal antibodies was employed in multi-color fluorescence experiments.
- Univariate and multivariate regression analyses were performed to assess prognostic significance.
Main Results:
- Poor prognosis was associated with bright CD34 expression (>15% blasts), co-expression of CD34 and CD33 (>60% blasts), CD14 expression (>30% leukemic cells), and MDR+ phenotype.
- Dim CD34 expression showed similar survival outcomes to CD34- AML patients.
- Multivariate analysis revealed that combined CD34 and CD33 expression, along with age, independently predicted shorter survival.
Conclusions:
- The co-expression of CD34 and CD33 on leukemic blasts is a significant independent prognostic marker in AML.
- Immunophenotypic analysis, particularly CD34/CD33 co-expression, can refine prognostic stratification in AML.
- These findings contribute to understanding discrepancies in the literature regarding CD34's prognostic role.
Abstract:
In order to elucidate the prognostic role of cytofluorimetry analysis of leukemic cells in AML, the immunophenotypic characteristics of blast cells obtained from 66 AML patients belonging to M0-M2 and M4-M5 FAB subtypes have been investigated by flow cytometry using a large panel of monoclonal antibodies (McAbs) utilized in single, double, and triple fluorescence experiments. On a univariate analysis, four different immunophenotypic blast cell characteristics were found to be associated with a poor prognosis: expression of CD34 "bright" (ratio > 10 between fluorescence emission of positive cells and that of negative (isotypic) control-P/N ratio: mean MESF value: 265,000) in > 15% blast cells, co-expression of CD34 and CD33 in > 60% blast cells, expression of CD14 in > 30% leukemic cells, the MDR+ ("multiple drug resistant") phenotype. In contrast, the duration of remission, and overall survival of AML patients showing a "dim" CD34 expression (P/N ratio: 3-10: mean MESF value: 49,000) was similar to that of CD34- AML patients, irrespective of the percentage of positivity for CD34, which was, however, a predictive factor of survival in patients with higher CD34 fluorescence intensities in their blastic population. No correlation between FAB subtypes, prognosis and immunophenotype was found. The multivariate regression analysis showed that, besides age, only the combined expression of CD34 and CD33 had independent prognostic meaning. Indeed, in each FAB subtypes the CD34+/CD33+ phenotype was associated with a shorter survival and a lower mitotic rate. These data may contribute to the understanding of the discrepancies so far observed in the literature regarding the prognostic role played by the CD34 expression on leukemic AML blasts.
