Nell, Zanre2024-11-182024-11-182024Nell, Zanre. (2024). A multicentre study to evaluate an in-house multiparameter immunophenotypic panel to identify precursor B-cells in the determination of measurable residual disease in paediatric B-cell acute lymphoblastic leukaemia [Master’s dissertation, University of the Witwatersrand, Johannesburg]. WireDSpace.https://hdl.handle.net/10539/42694A research report submitted in partial fulfillment of the requirements for the degree of Master of Medicine to the Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, 2024Background: Periodic assessment of measurable residual disease (MRD) is an important prognostic factor in the management of paediatric B-cell acute lymphoblastic leukaemia (ALL). Conventional polymerase chain reaction (cPCR) and multiparameter flow cytometry (MFC) are well-established in MRD determination, the latter with no current optimal immunophenotypic panel by international consensus. Objective: To determine whether an in-house immunophenotypic panel containing the discriminatory CD58-FITC (cluster of differentiation; fluorescein isothiocyanate) marker compares with cPCR in the detection of paediatric B-cell ALL MRD. Methods: This prospective descriptive validation study was performed on diagnostic and follow-up bone marrow aspirate samples, comparing an in-house immunophenotypic panel against the standardised commercial ClearLLab 10CTM B-cell/myeloid cell-2 (M2) panels in MRD assessment. These findings were then compared to cPCR to determine individual panel performance and predictive power. Results: Both immunophenotypic panels demonstrated 100% concordance in the identification of the leukaemia-associated immunophenotype (LAIP) on all diagnostic samples. The in-house immunophenotypic panel showed a higher sensitivity and specificity, and greater association with cPCR in MRD assessment in follow-up samples. In combination with shared backbone markers of the ClearLLab 10CTM B-cell/M2 panels, inclusion of CD58-FITC and CD81-APC-H7 (allophycocyanin- cyanine dye) proved most informative in accurate distinction between regenerating B-cell precursors and residual leukaemic cells. Conclusion: This work confirms the findings of previous studies, where discriminatory marker CD58- FITC in combination with backbone informative markers demonstrates both superior diagnostic and monitoring utility in paediatric B-cell ALL. The in-house immunophenotypic panel offers an attractive, comparable alternative in MRD determination in this patient population whilst awaiting cPCR results, raising the possibility of earlier clinical decision-making with potential improvement of morbidity and mortality outcomesen© 2024 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg.B-cell acute lymphoblastic leukaemiaMeasurable residual diseaseConventional polymerase chain reactionMultiparameter flow cytometryUCTDSDG-3: Good health and well-beingDissertationUniversity of the Witwatersrand, Johannesburg