Bortezomib Combination Therapy of Relapsed and Refractory Acute Lymphoblastic Leukemia in Children

Background & Aims. Despite significant success in the treatment of acute lymphoblastic leukemia (ALL) in children, relapses and drug resistance to the standard therapy remain the main cause of treatment failure. The addition of bortezomib to the combination therapy of relapsed ALL to change the sensitivity of blast cells may be a perspective approach to cure patients. The aim was to evaluate the efficacy and toxicity of the anti-relapse ALL treatment protocols REZ BFM 95/96 without bortezomib and COG AALL07P1 with bortezomib in relapsed and refractory ALL in children. Materials & Methods. The study included 54 children with a confirmed ALL of various localizations. From 1995 to 2011, ALL REZ BFM 95/96 treatment without bortezomib was administered to 26 patients. From 2011 to 2016, 28 children received COG AALL07P1 combination treatment with bortezomib. Results. The immediate treatment efficacy significantly higher in patients treated with bortezomib (85.7 % vs 57.6 %) after induction chemotherapy with the ALL REZ BFM 95/96. The analysis of the long-term outcomes (disease-free, event-free, overall survival) showed no significant differences between the groups. The event-free survival of patients with isolated bone marrow relapses for a period of 2 years was 20.3 ± 17.5 %. The tolerability of the program was acceptable, complications developing during myelosuppression were not associated with the administration of bortezomib. Conclusion. The intensification of induction chemotherapy in recurrent remission according to COG AALL07P1 protocol with the addition of bortezomib allowed to increase the number of complete remissions including MRD negative ones

Evaluation of Minimal Residual Disease in B-Lineage Acute Lymphoblastic Leukemia Using EuroFlow Approaches

Background & Aims. Evaluation of the minimal residual disease (MRD) at different stages of chemotherapy is one of key prognostic factors and a factor of stratification of patients into risk groups in acute lymphoblastic leukemia (ALL). The MRD detection on Day 15 and at later stages is based on identifying blast cells with a leukemia-associated immune phenotype. The aim is to assess the potential of 8-color standardized EuroFlow panels and to detect individual criteria for MRD monitoring during primary diagnosis. Materials & Methods. The analysis included data on the primary immune phenotype and MRD assessment during chemotherapy in 10 adults and 35 children with a confirmed diagnosis of B-cell precursors ALL. Results. The ALL phenotype characteristics at the stage of primary diagnosis permit to make the most complete description of the of 8-color standardized EuroFlow panels. This gives an opportunity to select the most informative antigen combinations for further MRD monitoring. Combinations with CD58/CD38, CD81/СD9 antigen expression, as well as assessment of pan-myeloid CD13, CD33 antigen co-expression may be recommended as the most frequent aberrant immune phenotypes of blast cells in ALL. As for B-lineage progenitor cells in children on Day 15 of the induction therapy, a detection of TdT+ сyCD22+ cell population is necessary in addition to the quantification of CD10+ and/or CD34+ В-lineage progenitor cells. Conclusion. Therefore, the 8-color standardized EuroFlow panels permit not only to characterize the primary ALL immune phenotype in details, but may also be widely used for MRD evaluation at all stages of chemotherapy

A Case Report of Myeloid Sarcoma in a Child

The diagnosis of myeloid tumors is based on a complex approach and causes significant difficulties especially in young children. Morphologic, immunologic, cytogenetic, molecular and biologic data on myeloid sarcoma are presented based on the literature data and own clinical case. Treatment results of myeloid sarcoma (especially in the high risk group) are unsatisfactory and should be improved

Diagnosis of Acute Lymphoblastic Leukemia Originating From T-Lineage Precursors and Approaches to Minimal Residual Disease Monitoring

Background. Minimal residual disease (MRD) is an independent prognostic factor in acute lymphoblastic leukemia (ALL) in children. The immunological assessment of MRD cell count is based on aberrant immunophenotype of tumor lymphoblasts. However, in the case of ALL originating from T-lineage precursor cells (T-ALL) no clear aberrancy criteria have been defined, yet. Flow-cytometric MRD assessment in T-ALL can be based on characteristics of normal T-cell ontogenesis, i.e. the absence of normal T-lineage precursor cells (T-LP) in bone marrow. Aim. To assess the feasibility of immunological method of flow cytometry for MRD detection based on T-LP immunophenotype on Days 15 and 33 of treatment of T-ALL children. Materials & Methods. The analysis included the data on primary immunophenotype and MRD assessment on Dayы 15 and 33 of treatment of 31 T-ALL patients in the age of 2–17 years. In the majority of cases (61.3 %) the cortical/thymic immuno-subvariant of ALL was detected, in the rest of cases (38.7 %) it was the pre-T-cell one. Diagnosis was based on cumulative results of morphocytochemical and immunological bone marrow analyses. Assessing the MRD state the morphological and immunological analyses of bone marrow aspirate were carried out in parallel with one and the same tube. All patients enrolled in the trial were treated at Scientific Research Institute of Pediatric Oncology and Hematology of NN Blokhin National Medical Cancer Research Center according to the ALL IC-BFM 2009 protocol. Results. Our study demonstrated that at all therapy stages MRD can be assessed by the unified immunological method based on detecting cyCD3+CD7+/++smCD3– (T-LP) immunophenotype cells. It is important to ensure that the correct clones of monoclonal antibodies are used for detecting CD3 cytoplasmic and membrane molecules (UCHT1 and SK7, respectively). Standard risk group included no patients. The majority of patients (76.2 %) treated according to ALL IC-BFM 2009 protocol were assigned to medium risk group on Day 15 of treatment. By Day 33 a quarter of them (25 %) was included into high risk group. Conclusion. The capabilities of multicolor flow cytometry allow for the most complete characterization of primary immunophenotype of tumor T-cell lymphoblasts for further search of leukemia-associated immunophenotypes. Specific ontogenesis features of normal T-cells enable unification of immunological approaches to MRD assessment at all stages of T-ALL therapy