Methodological aspects of diagnostics and minimal residual disease monitoring in infant acute leukemias

Hereby we present methodological aspects and prognostic significance of minimal residual disease (MRD) monitoring in infant acute leukemias. Based on our own experience we made algorithm for detection of MRD in this group of patients. We conclude that general concordance between MRD detection by flow cytometry and real-time polymerase chain reaction (PCR) for fusion gene transcripts achieved 87.0 %. Concordance was significantly lower during induction in comparison to consolidation/intensification and relapse treatment (78.6; 90.4 and 93.4 %, correspondingly; p = 0.002). It was not dependent on presence of normal B-cell precursors. Concordance between MRD results obtained by qualitative real-time PCR in bone marrow and peripheral blood samples was 84.5 %. Interestingly, all discrepant results (22 samples 15.5 %) were MRD-positive in bone marrow, but negative in peripheral blood. Despite high qualitative concordance rate between MRD detection in bone marrow and peripheral blood samples we could not show prognostic value of MRD monitoring in peripheral blood by fusion gene transcripts. Multivariate analysis revealed that MRD-positivity at time-point 4 in bone marrow was the only significant and independent prognostic factor of unfavorable outcome in the observed group of patients (hazard ratio 7.326; 95 % confidence interval 2.378–22.565)

Modeling of complex of catalase «А» from Saccharomyces Cerevisiae with NADPH for its geometry prediction

NADPH weakly binds to Catalase «А» from Saccharomyces cerevisiae, so geometry of bound ligand is not known from X-ray crystallography. To resolve this issue com-plexes of catalase «А» from Saccharomyces cerevisiae with NADPH and it s frag-ments - inorganic momophosphates and 2 ,5 -ADP was modeled with molecular me-chanics methods. Binding site of NADPH 2 -phosphate in KATA was detected and models of 2’,5 -ADP as individual molecule and as fragment of NADPH in complexes with catalase «А» were proposed. These model data are in good agreement with known experimental results (electron density). Position of nicotinamid-ribosid is not determined.Каталаза «А» из Saccharomyces cerevisiae образует слабый комплекс с НАДФН2, поэтому его геометрия в ренгеноструктурных исследованиях не установлена. Цель настоящей работы - предсказание геометрии НАДФН2 и его фрагментов - неорганических монофосфатов и 2',5'-АДФ в связанном с ферментом состоянии методом молекулярно-механического моделирования. Результаты расчетов позволили надежно локализовать сайт связывания 2 -фосфата НАДФН2 в этой каталазе, а также предложить обоснованные модели 2',5'-АДФ в форме индивидуальной молекулы и в составе НАДФН2 в комплексе с каталазой «А», согласующиеся с известными экспериментальными данными по электронной плотности. Положение никотинамидной части НАДФН2 на основе анализа полученных моделей окончательно не установлено

Aetiology of infectious complications in children with oncohematological diseases

The article presents the results of microbiological studies of different biomaterials in the diagnosis of infectious complications in children with oncohematologicaldiseases after bone marrow transplantation.Gram-negative bacteria both endogenous and possibly nosocomial origin are lead among the detected microorganisms.В статье приведены результаты микробиологических исследований различных биоматериалов, полученных при диагностике инфекционных осложнений у детей с онкогематологическими заболеваниями после трансплантации. Среди обнаруженных микроорганизмов лидируют грамотрицательные бактерии как эндогенного, так и, возможно, нозокомиального происхождения

The role of nelarabine in the treatment of T-cell acute lymphoblastic leukemia: literature review and own experience

Aim. The analysis of experience of nelarabine use in refractory/relapsed T-cell acute lymphoblastic leukemia (T-ALL) depending on the immunophenotype and the line of therapy. Materials and methods. All the patients with relapsed or refractory T-ALL aged from 0 to 18 years who received treatment with nelarabine as a part of the therapeutic element R6 were included in the study. For all patients a detailed immunological analysis of leukemia cells with discrimination of immunological variants TI, TII, TIII or TIV was performed. Patients administered with nelarabine as a first therapeutic element were referred to the first-line therapy group, other patients were referred to the second-line therapy group. Nelarabine was administered as intravenous infusion at a dose of 650 mg/m2, on days 1-5. Allogeneic hematopoietic stem cells transplantation (allo-HSCT) was considered for all patients. Results. From 2009 to 2017, 54 patients with refractory/relapsed T-ALL were treated with nelarabine. Five-year event-free survival (EFS) and overall survival (OS) was 28% for all patients, cumulative risk of relapse (CIR) was 27%. EFS was significantly higher in nelarabine first-line therapy group in comparison with second-line therapy group (34±8% vs 8±8%, p=0,05). In patients after allo-HSCT EFS, OS and CIR were 51±10%, 50±10% and 39,1±9,5% accordingly. The best results were achieved in patients with TI immunophenotype. No toxicity-related mortality as well as severe neurologic complications or discontinuation of therapy associated with use of nelarabine were reported. Conclusion. The use of nelarabine is an effective strategy for the treatment of relapsed and refractory T-ALL. The best treatment outcomes were obtained in patients with TI immunophenotype and in the first-line therapy group. Optimal dosage regimens can be established during controlled clinical trials

Features of diagnostics and surgical treatment of ovarian tumors in children

The purpose of current work was to assess prognostically significant laboratory parameters in patients with ovarian tumors, as well as to determine optimal types of surgical treatment.Целью работы являлись оценка прогностически значимых лабораторных показателей, а также определение наиболее оптимальных видов хирургического лечения пациенток с опухолями яичников

Standard of morphological and molecular biological investigations in neuroblastoma

87 cases of primary neuroblastoma verified according to current standards of morphological and molecular genetic diagnostics are reviewed in the paper. Morphological variants and diagnostics criteria of tumor as well as risk groups stratification criteria are summarized. MYCN gene amplification and 1p deletion are designated as adverse molecular genetic features. Prognostic impact of genetic aberrations and unfavorable histology were calculated using event-free and overall survival values.В статье приведены результаты морфологического и молекулярно-биологического исследования 87 случаев нейробластомы у детей, верифицированных с учетом принятых стандартов исследования данной опухоли. Приведены морфологические варианты и критерии диагностики нейробластомы в рамках современных классификаций, а также современные подходы к стратификации больных нейробластомой на группы риска для проведения селективной риск-адаптированной терапии. Амплификация гена MYCN и делеция короткого плеча хромосомы 1 в клетках нейробластомы являются неблагоприятными прогностическими факторами и используются в различных схемах стратификации пациентов на группы риска. Проанализирована бессобытийная выживаемость (БСВ) и общая выживаемость (ОБ) в группах пациентов при наличии генетических аберраций и при неблагоприятной гистологической форме опухоли

Comperetive analysis of minimal mearsurable disease monitoring by flow cytometry and real-time quantitative pcr results in infants with acute lymphoblastic leukemia

The article contains qualitative and quantitative assessment of relation of monitoring MRD results in infants with B-cell acute lymphoblastic leukemia by FCM and quantitative RT-PCR.В статье приведена оценка качественной и количественной зависимости между результатами определения МОБ методами ПЦ и ОТ-ПЦР-РВ у детей первого года жизни с острым лимфобластным лейкозом из В-линейных предшественнико

Translocation t(1;11)(p32;q23) with MLL-EPS15 fusion gene formation in acute leukemias: a review and 6 new case reports. Approaches to minimal residual disease monitoring

We performed clinical and laboratory characterization of patients with rare translocation t(1;11)(p32;q23) leading to MLL-EPS15 fusion gene formation. Study cohort consisted of 33 primary acute leukemia (AL) cases including 6 newly diagnosed and 27 patients previously described in literature. Among study group patients t(1;11)(p32;q23) was found most frequently in infant AL cases (median age 8 months). In acute lymphoblastic leukemia (ALL) male/female ratio was 1:3, in acute myeloid leukemia (AML) it was 1:1. Additional cytogenetic aberrations in 38 % of patients were revealed. The most frequent breakpoint position in EPS15 gene was intron 1. Four different types of MLLEPS15 fusion gene transcripts were detected. Primers-probe-plasmid combination for MLL-EPS15 fusion gene transcript monitoring by realtime quantitative polymerase chain reaction (RQ-PCR) was developed and successfully applied. In 3 patients RQ-PCR was done on genomic DNA for absolute quantification of MLL-EPS15 fusion gene. High qualitative concordance rate (92 %) was noted between minimal residual disease data obtained in cDNA and genomic DNA for MLL-EPS15 fusion detection.</p

The MLL recombinome of acute leukemias in 2017

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients