Flow cytometric significance of cellular alkaline phosphatase activity in acute myeloid leukemia

Abstract

In this prospective hospital-based cohort study that included 43 newly diagnosed patients with acute myeloid leukemia, flow cytometric cellular alkaline phosphatase (ALP) activity within primitive leukemic cells allowed us to identify two groups of patients at diagnosis according to the numbers of leukemic blasts expressing ≥ 12% of ALP+ cells (27 patients, Group A) and less than 12% of ALP+ cells (16 patients, Group B). Differences in outcome for complete response, relapse or treatment resistance, and exitus were statistically analyzed and were significant, when comparing the two groups. The overall survival (OS) and event-free survival (EFS) differences between Group A and B were statistically significant. The survival of Group A patients was significantly shorter than those for Group B. No significant relationship was detected in outcome when comparing ELN prognostic-risk group based on cytogenetic and molecular profile (patients in the favorable, intermediate, and adverse risk groups). Flow cytometric cellular ALP activity at diagnosis may be used to estimate relapses and disease persistence more accurately. The limitations of our study include the small number of patients enrolled and a short follow-up, due to its prospective nature.

Erythrocyte lysing solutions have a detrimental effect in flow cytometric dendritic cell detection

“…Briefly, blood samples are incubated with a DNA stain and with antibodies directed against the markers of choice, avoiding the use of lysing and washing steps. Moreover, these methodologies allow to simultaneously study cell function, by preserving a native-like state of the cells [46][47][48][49]. By using these methods, accurate results can be obtained, with low variability and high reproducibility.…”

Flow-cytometry-based protocols for human blood/marrow immunophenotyping with minimal sample perturbation

“…The fluorescent threshold will then capture only CD45+ ( Figure 5 ) or alternatively nucleated cells ( Figures 6 and 7 ), and will contribute to dramatically increasing throughput, even allowing identification of rare cells. We have routinely used this method for CD34+ cell discrimination ( Rico et al., 2019 ; Alvarez-Larran et al., 2002 ; Fornas et al., 2000 ). The identification of nucleated red blood cells can also be validated using fluorescent conjugates used to target CD45 negative cells, in combination with glycophorin A (GpA), a sialoglycoprotein expressed on human red blood cells and erythroid precursor cells, useful for red cell differentiation studies, as we previously described in Cytometry Part B ( Fornas et al., 2002 ).…”

“…Over the years we have successfully deployed this protocol using live and intact blood or marrow cells, such as those aimed at the study of healthy and pathological hematopoietic stem cells ( Fornas et al., 2000 ), erythroid differentiation ( Fornas et al., 2002 ), oxidative burst and neutrophil-platelet complexes ( Avendaño et al., 2008 ), phagocytosis ( Lecube et al., 2011 ), enzymatic activity ( Rico et al., 2016 , 2019 ; Bardina et al., 2020 ), reactive oxygen species production ( Cossarizza et al., 2019 ), cell-mediated cytotoxicity ( Rico et al., 2021a ), or to the study changes in conformation of the extracellular domain of PD-L1 ( Rico et al., 2021b ).…”

Persistence of Chronic Lymphocytic Leukemia Stem-like Populations under Simultaneous In Vitro Treatment with Curcumin, Fludarabine, and Ibrutinib: Implications for Therapy Resistance

“…For this reason, it is essential to have alternatives to identify these populations. One of these alternatives is functional analysis, which uses cell physiology instead of phenotypic markers to determine cell populations [9][10][11][12].…”