Prisca M J Theunissen, Lukasz Sedek, Valerie De Haas, Tomasz Szczepanski, Alita Van Der Sluijs, Ester Mejstrikova, Michaela Nováková, Tomas Kalina, Quentin Lecrevisse, Alberto Orfao, Arjan C Lankester, Jacques J M van Dongen, Vincent H J Van Der Velden, EuroFlow Consortium
British journal of haematology 2017 JulFlow 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. © 2017 John Wiley & Sons Ltd.
Prisca M J Theunissen, Lukasz Sedek, Valerie De Haas, Tomasz Szczepanski, Alita Van Der Sluijs, Ester Mejstrikova, Michaela Nováková, Tomas Kalina, Quentin Lecrevisse, Alberto Orfao, Arjan C Lankester, Jacques J M van Dongen, Vincent H J Van Der Velden, EuroFlow Consortium. Detailed immunophenotyping of B-cell precursors in regenerating bone marrow of acute lymphoblastic leukaemia patients: implications for minimal residual disease detection. British journal of haematology. 2017 Jul;178(2):257-266
PMID: 28419441
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