Comparison of methods for assessment of minimal residual disease in childhood B-lineage acute lymphoblastic leukemia

Abstract

The level of minimal residual disease (MRD) early in treatment of acute lymphoblastic leukemia (ALL) strongly predicts the risk of marrow relapse. As a variety of methods of varying complexity have been separately used for detecting and quantifying MRD, we compared the prognostic utility of three methodsmeasurement of blast percentage on day 14 of treatment, detection of monoclonality on day 14 or day 35, and measurement of MRD by PCR-based limiting dilution analysis on day 14 or day 35. The study group comprised 38 children aged 1-15 with Philadelphia-negative B-lineage ALL who were uniformly treated and followed until relapse or for a minimum of 5 years. We also studied some of the technical factors which influence the ability to detect MRD. Measurement of blast percentage on day 14 by an expert morphologist, detection of monoclonality on day 35, and PCR-based measurement of MRD levels on days 14 and 35 all showed significant ability to divide patients into prognostic groups. Measurement of blast percentage on day 14 by routine morphology or detection of monoclonality on day 14 were not useful. The quality of DNA samples varied greatly, as determined by amplifiability in the PCR. However, virtually all amplifiable leukemic targets in a sample were detectable which suggests that the level of detection achieved by limiting dilution analysis is essentially determined by the amount of DNA which it is practicable to study. We conclude that quantification of MRD at the end of induction provides the full range of prognostic information for marrow relapse but is complex; detection of monoclonality on day 35 is simple and has good positive predictive value; and quantification of MRD on day 14 merits further study. PCR-based methods for measurement of MRD levels should incorporate a correction for variation in DNA amplifiability. Leukemia (2001) 15, 385-390.

A simplified minimal residual disease polymerase chain reaction method at early treatment points can stratify children with acute lymphoblastic leukemia into good and poor outcome groups

“…Simplified techniques using standard PCR, 40,41 RQ-PCR 42 or GeneScan 43,44 have proven to be valid for the study of MRD in ALL. Recently, a simplified and relatively inexpensive technique of MRD detection on day 19 of induction therapy by flow cytometry using a panel of only three monoclonal antibodies was able to identify children with B-lineage ALL with a very good response to treatment.…”

PCR detection of clonal IgH and TCR gene rearrangements at the end of induction as a non‐remission criterion in children with ALL: Comparison with standard morphologic analysis and risk group classification

“…In vitro experiments in which leukemic cells were diluted with peripheral blood or bone marrow mononuclear cells have shown sensitivities ranging from 0.5-1.5Â10 À1 [17] to 6Â10 À4 [41]. In vivo, detection of clonality is possible at levels of 10 À3 or less [21,40,42]. In the present study, this technique led to the detection of one leukemic cell detected in a pool of 10 2 (more common) to 10 3 bone marrow cells.…”

“…PCR detection of clonal Ig and TCR gene rearrangements using consensus primers is a simpler and less expensive method, which may be routinely used by a larger number of laboratories, although it is a nonquantitative technique of low and uncertain sensitivity. However, few studies have been conducted on the use of this technique in the analysis of MRD [21,39,40].…”

Modelling a minimal residual disease‐based treatment strategy in childhood acute lymphoblastic leukaemia

“…Such differences can be substantial. They are often ignored but they can be easily corrected by quantifying a non‐leukaemic target, such as the N‐ras gene, of approximately the same size as the leukaemic target (Brisco et al , 2001).…”