Detection of minimal residual disease in acute leukemia by flow cytometry

Abstract

Patients with acute leukemia in clinical remission may still have up to 1010 residual malignant cells (the upper limit of detection by standard morphologic techniques). Sensitive techniques to detect minimal residual disease (MRD) may allow better estimates of the leukemia burden and help the selection of appropriate therapeutic strategies. Flow cytometry and polymerase chain reaction have emerged as the most promising methods for detecting submicrospopic levels of leukemia. Flowcytometric detection of MRD is based on the identification of immunophenotypic combinations expressed on leukemic cells but not on normal hematopoietic cells. It affords the detection of one leukemic cell among 10,000 normal bone marrow cells, and can be currently applied to at least two thirds of all patients with acute leukemia. Prospective studies in large series of patients have demonstrated a strong correlation between MRD levels during clinical remission and treatment outcome. Therefore, MRD assays can be reliably used to assess early response to treatment and predict relapse. In this review, we discuss methodologic aspects and clinical results of flowcytometric detection of MRD in patients with acute leukemia. Cytometry (Comm. Clin. Cytometry) 38: 139–152, 1999. © 1999 Wiley‐Liss, Inc.

Comparative analysis of flow cytometry and polymerase chain reaction for the detection of minimal residual disease in childhood acute lymphoblastic leukemia

“…The single patient with no suitable immunologic markers or antigen receptor-gene rearrangements could be monitored by using PCR amplification of MLL-AF4. Further, there may be occasional false-negative findings by flow cytometry due to immunophenotypic changes during therapy, 2,35 and by PCR due to oligoclonality at diagnosis and/or clonal evolution during the course of the disease. [36][37][38][39][40][41] The use of the two methods in tandem should offset the possibility of false-negative MRD results due to these events.…”

Comparative analysis of minimal residual disease detection using four-color flow cytometry, consensus IgH-PCR, and quantitative IgH PCR in CLL after allogeneic and autologous stem cell transplantation

“…In accordance with the literature on MRD in acute leukemias, [34][35][36][37] we defined that at least 20 CLL cells forming a population in light scatter were required as evidence for MRD (absolute specificity threshold). In addition, a sample was judged as MRD positive only if the CLL cell number exceeded the relative specificity threshold.…”

“…38 In accordance with reports on MRD flow for acute leukemias, we defined 20 events as absolute specificity threshold. [34][35][36][37] A second prerequisite for specific MRD detection is that the number MRD-positive cells is higher than the expected number of false positive events per 100 000 leukocytes analyzed (relative specificity threshold). The relative specificity threshold is particularly dependent on debris and unspecific antibody binding.…”

Reply to the letter from von Stackelberg et al

“…To prevent the possibility of phenotypic shift, we always recommend the use of multiple marker combinations whenever possible. [3][4][5][6] Likewise, more than one allele-specific oligonucleotide probe should be used with PCR to offset the risk of false-negative results due to oligoclonality and clonal evolution. 7 Regarding the sensitivity of flow cytometry, one should make a distinction between flow cytometric techniques that rely on combinations that are not expressed by normal hematopoietic cells (including hematogones) and those that use marker combinations that are not completely leukemia specific.…”

“…V H gene analysis of hairy cell leukemia reveals a homogeneous mutation status and suggests its marginal zone B-cell origin Leukemia (2004) [3][4][5] To verify this issue, we analyzed the V H mutation status and V H gene usage of 20 HCL cases.…”