Detailed immunophenotyping of B-cell precursors in regenerating bone marrow of acute lymphoblastic leukaemia patients: implications for minimal residual disease detection

Br J Haematol. 2017 Jul;178(2):257-266. doi: 10.1111/bjh.14682. Epub 2017 Apr 17.


Flow cytometric detection of minimal residual disease (MRD) in children with B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) requires immunophenotypic discrimination between residual leukaemic cells and B-cell precursors (BCPs) which regenerate during therapy intervals. In this study, EuroFlow-based 8-colour flow cytometry and innovative analysis tools were used to first characterize the immunophenotypic maturation of normal BCPs in bone marrow (BM) from healthy children, resulting in a continuous multiparametric pathway including transition stages. This pathway was subsequently used as a reference to characterize the immunophenotypic maturation of regenerating BCPs in BM from children treated for BCP-ALL. We identified pre-B-I cells that expressed low or dim CD34 levels, in contrast to the classical CD34high pre-B-I cell immunophenotype. These CD34-dim pre-B-I cells were relatively abundant in regenerating BM (11-85% within pre-B-I subset), while hardly present in healthy control BM (9-13% within pre-B-I subset; P = 0·0037). Furthermore, we showed that some of the BCP-ALL diagnosis immunophenotypes (23%) overlapped with CD34-dim pre-B-I cells. Our results indicate that newly identified CD34-dim pre-B-I cells can be mistaken for residual BCP-ALL cells, potentially resulting in false-positive MRD outcomes. Therefore, regenerating BM, in which CD34-dim pre-B-I cells are relatively abundant, should be used as reference frame in flow cytometric MRD measurements.

Keywords: B cells; acute leukaemia; flow cytometry; minimal residual disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Antigens, CD34 / metabolism
  • Bone Marrow / physiology
  • Cell Differentiation / physiology
  • Child, Preschool
  • Flow Cytometry
  • Gene Rearrangement, B-Lymphocyte / immunology
  • Humans
  • Immunoglobulin Heavy Chains / immunology
  • Immunophenotyping / methods
  • Male
  • Neoplasm, Residual
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / diagnosis*
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / immunology
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / physiopathology
  • Precursor Cells, B-Lymphoid / immunology
  • Precursor Cells, B-Lymphoid / pathology
  • Precursor Cells, B-Lymphoid / physiology*
  • Regeneration


  • Antigens, CD34
  • Immunoglobulin Heavy Chains