Flow Cytometric Minimal Residual Disease Analysis in Acute Leukemia: Current Status

Precision Isolation of Circulating Leukemia Cells in Chronic Myelogenous Leukemia Patients Using a Novel Microfluidic Device and Its Clinical Applications

Chronic Myelogenous Leukemia (CML) is a prevalent hematologic malignancy characterized by the malignant transformation of myeloid cells and their proliferation in the peripheral blood. The management of CML poses significant challenges, particularly in detecting and eradicating minimal residual disease, which is crucial for preventing relapse and improving survival outcomes. Traditional minimal residual disease detection methods, such as bone marrow aspiration, are invasive and have limitations which include the potential for sampling errors and false negatives. This study introduces a novel label-free microfluidic chip designed for the segregation and recovery of circulating leukemia cells, offering a non-invasive liquid biopsy approach with potential applications in precision medicine. Over July 2021 to October 2023, we recruited 56 CML patients across various disease stages and collected blood samples for analysis using our microfluidic device. The device demonstrated high efficacy in isolating circulating leukemia cells, with an optimal capture efficiency of 78% at a sample flow rate of 3 mL/h. Our results indicate that the microfluidic device can efficiently segregate and quantify circulating leukemia cells, providing a detailed understanding of CML progression and treatment response. The significant reduction in circulating leukemia cell counts in patients in complete remission highlights the device's potential in monitoring treatment efficacy. Furthermore, the device's sensitivity in detecting minimal residual disease could offer a more reliable prognostic tool for therapeutic decision-making in CML management.

A concise review of flow cytometric methods for minimal residual disease assessment in childhood B-cell precursor acute lymphoblastic leukemia

Minimal residual disease refers to a leukemia cell population that is resistant to chemotherapy or radiotherapy and leads to disease relapse. The assessment of MRD is crucial for making an accurate prognosis of the disease and for the choice of optimal treatment strategy. Here, we review the advantages and disadvantages of the available genetic and phenotypic methods and focus on the multiparametric flow cytometry as a promising method with greater sensitivity, speed, and standardization options. In addition, we discuss how the application of automated data analysis outweighs the use of complex combinations of windows and gates in classical analysis, thus eliminating subjective evaluation.

Impact of pre-transplantation minimal residual disease (MRD) on the outcome of Allogeneic hematopoietic stem cell transplantation for acute leukemia

OBJECTIVE

To investigate the impact of minimal residual disease (MRD) before allogeneic hematopoietic stem cell transplantation (allo-HSCT) on the outcome of acute leukemia.

METHODS

Data from 114 patients who were diagnosed with acute leukemia (AL) and underwent allo-HSCT between Jan 2013 and Dec 2019 were collected and analyzed. The patients were attributed into MRD positive (MRD+) group and MRD negative (MRD-) group.

RESULTS

Among the 114 acute leukemia patients, there were 32 MRD+ patients before transplantation, and 82 MRD- patients. No significant difference was found between the MRD+ group and the MRD- group in the incidence of acute graft-versus-host disease (aGvHD) (p = 0.09). Compared with the MRD+ group, the MRD- group had a higher incidence of chronic graft-versus-host disease (cGvHD) (p = 0.008). There is no significance in relapse between the two groups (p = 0.084), while the incidence of relapse was seemingly higher in the MRD+ group: 36.9% Vs 19.7% . We attributed to the lack of sample size and NRM in MRD+ group was remarkably higher. The MRD+ group had significantly worse one-year overall survival (OS) ( , p = 0.003) and one-year progression-free survival (PFS) (, p = 0.009). In the multivariate analysis, MRD+ was an independent prognostic factor for OS (HR = 1.898; 95%CI 1.042-3.457; p = 0.036).

CONCLUSION

Pre-transplantation MRD positive status is a risk factor for survival and prognosis after HSCT. Upon this, emphasis should be put on (1) screening more efficient chemo regimen with targeted agents, to help patients reach and keep MRD- status before transplantation; (2) designing better management with different GvHD prophylaxis treatment, timely disease monitoring and preemptive intervention on relapse.

Correlation Study on HLA-DR and CD117 (c-Kit) Expressions: Its Prognosis and Treatment Response in Acute Myeloid Leukemia Patients

Introduction

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. HLA-DR and CD117 (c-Kit) are important diagnostic markers of AML. Our objective is to determine the prognostic significance of HLA-DR and CD117 expressions in newly diagnosed AML patients and determine the correlation between HLA-DR and CD117 expressions and other prognostic markers such as cytogenetic abnormalities, FLT3-ITD, response to treatment, and patient’s survival.

Methods

This study included 100 newly diagnosed AML patients. All patients were subjected to clinical, morphological, cytochemical, cytogenetic analysis, molecular genetic analysis to detect FLT3-ITD, and Flowcytometric detection of HLA-DR, CD117, and CD 34.

Results

The results showed that HLA-DR expression was found in 75 patients (77.3%), while CD117 expression was found in 63 patients (64.9%). Patients with HLA-DR expression showed significantly higher mean Hb concentration, significantly higher platelet count, associated with AML-FAB subtypes (M0, M1, and M2), CD34 expression, and favorable cytogenetic group. M3 subtype was significantly associated with HLA-DR-ve. While patients with CD117 expression showed significantly lower platelets count. Double positive patients (HLA-DR+ve/CD117+ve) showed significant association with the intermediate cytogenetic group, while double-negative patients (HLA-DR-ve/CD117-ve) were associated with the favorable and intermediate cytogenetic group and either positive (HLA-DR+ve /CD117-ve or HLA-DR-ve/CD117+ve) associated with poor cytogenetic groups. FLT3-ITD expression had significantly worse overall survival.

Conclusion

The current study suggested that the expression of CD117 and HLA-DR may be a prognostic marker in AML, as they are associated with M0, M1, and M2 FAB subtypes; moreover, patients with combined HLA-DR and CD117 positive expression are associated with CD34 expression and intermediate cytogenetic group.