Подходы к оценке минимальной остаточной болезни при В-линейных острых лимфобластных лейкозах в условиях таргетной терапии

Background. Flow cytometry (FC) algorithms of detection of minimal residual disease (MRD) are well standardized, and approximate to molecular biologic methods. However, besides informative leukemia-associated aberrant immunophenotype, which are selected taking into account a tumor phenotype at diagnostics stage, it is necessary to consider specificity of the provided taget therapy and its influence on a cell. Objective: to offer stable combinations of antigens to identify B-cell precursors in patients on therapy of blinatumomab. Materials and methods. Clinical observation of patient G. 4 years old with B-cell precursors acute lymphoblastic leukemia (ALL) (pre-pre-B immunosubtype), whom after 3 bloks of reinduction therapy, taking into account MRD-positive status, blinatumomab was appointed as a monotherapy. Tumor immunophenotype was characterized in details by FC protocol according to EuroFlow in debute and relapse of the disease. MRD monitoring was provided by 8-color FC taking into account personalized leukemia-associated aberrant immunophenotypes. Results. In patient with B-cell precursors ALL received blinatumomab, the strategy of MRD monitoring was changed. Due to the lack of CD19 expression, identification of B-cell precursors was based on expression of cyCD22 in combination with nuclear TdT and CD10. Conclusion. In case of blinatumomab’s appointment during B-cell precursors ALL therapy, it is necessary to change the strategy of B-cell precursors identification, due to the lack of CD19 expression. Detection of B-cell precursors should be provided by assessment of other pan-B lineage antigens. First of all, it is cyCD22 or cyCD79a in combination with nuclear TdT and CD10, within the limits of nucleated cells of the sample.