Immunological features of B-linear progenitors on the 15th day of acute lymphoblastic leukemia therapy in children. Comparison of minimal residual disease assessment protocols and own results

Evaluation of minimal residual disease (MRD) on the 15th day of treatment of acute lymphoblastic leukemia from B-linear precursors (B-ALL) in children is of key importance in the prognosis of the disease. When evaluating the MRD, it is necessary to take into account the features of the primary immunophenotype of tumor B-lymphoblasts. To assess the MRD on the 15th day of treatment several immunological approaches have been proposed that have a general concept, but differ in fundamentally important details. The purpose of this work was to analyze the established flow cytometry (FC) protocols of the main research groups (BerlinFrankfurt-Munster Group, St. Jude Hospital, Children’s Oncology Group) and to compare the results evaluated according to those approaches. This study was approved by the Independent Ethical Committee N.N. Blokhin National Medical Cancer Research Center. The study included 131 patients with B-ALL aged 1 to 17 years (median 5.53). Pre-Pre-B immunosubvariant prevailed (92.4%). A morphological (myelogram count) and immunological (MRD assessment) study of the BM was performed in all patients on the 15th day. Comparing the FC protocols of the MRD on the 15th day, it was shown that CD10 was a more reliable criterion for the detection of B-LP in comparison with CD34. The expression of CD45 may serve as an additional criterion for the detection of B-LP. The recalculation of the mononuclear cells is a more stringent criterion for determining the MRD. The scientific novelty is that for the first time on the 15th day, a detailed comparison of flow cytometry data with a cytological picture of the bone marrow was carried out. It was shown for the first time that not all B-LP detected on the basis of CD10+ /CD19+ /CD34+ /CD45low are aberrant according to CD58/CD38.

acute lymphoblastic leukemia, minimal residual disease, flow cytometry, B-linear progenitors, immunophenotype