[Development of program therapy for patients with acute myeloid leukemia under the age of 60 years, based on the principles of differentiated effects].

AIM: To analyze the results of treatment in patients with acute myeloid leukemia (AML) within protocols AML-17 and modified AML-17 (mOML-17) as part of two consecutive pilot studies in order to develop the best treatment strategy for AML patients aged below 60 years. MATERIALS AND METHODS: The study included 89 AML patients who were aged below 60 years and received treatment within the AML-17 and mOML-17 protocols. Cytogenetic and molecular genetic studies were performed in all patients. The presence of mutations in the FLT3, NPM1, CEBPa genes was assessed by fragment analysis. 35 patients underwent a study for mutTP53, mutRUNX1 using next generation sequencing (NGS). The minimum residual population of tumor cells was evaluated by multicolor flow cytometry. Statistical analysis was performed using the procedures of the SAS 9.3 package. RESULTS: Complete remission (CR) was achieved in 89.7% of patients treated with intensive chemotherapy (CT) courses and in 52.4% of patients treated with low-dose CT courses. 8.8% of intensively treated patients were refractory to therapy, and 38% did not respond to low-dose exposure. The early mortality rate was 3%. The overall survival and disease-free 3-year survival for patients included in 2 consecutive studies was were 60% and 67%, respectively. The level of minimal residual disease (MRD) after the first course of induction CT was an important prognostic indicator. The three-year relapse-free survival for patients in whom CR was achieved after the first course of induction CT and in whom MRD was not detected (MRD-negative status was obtained) was 90% compared to 43% for patients who were MRD positive after the first course of induction CT (p=0.00001). CONCLUSION: The key factor that significantly affects the long-term results of therapy is the rate of MRD after the first course of induction CT.

[Multipotent mesenchymal stromal cells application for acute graft versus host disease treatment].

AIM: Analysis of the effectiveness of the MSCs aministration as the second- or third-line therapy of acute GVHD (aGVHD) resistant to glucocorticosteroid treatment. MATERIALS AND METHODS: The study included 35 patients who received MSCs obtained from the bone marrow of healthy donors as a treatment of steroid-resistant aGVHD. The clinical parameters of patients, MSCs cultural characteristics, the MSC expression profile for various genes including those involved in immunomodulation, expression of cells surface markers, the source of MSCs, as well as the frequency and number of MSC administrations were analyzed. RESULTS: Response to therapy was achieved in 74% of cases, a complete response was reached in 13 (37%) patients, partial response/clinical improvement was demonstrated in 13 (37%). This treatment was ineffective in 9 patients. The prediction of a group of patients with good response to MSC therapy turned to be impossible. The differences between the effective and ineffective for the GVHD treatment MSCs samples were found. The effective ones were characterized with a decreased total MSCs production and an increase in the main histocompatibility complex and PDL-1 antigens expression. CONCLUSION: These data allow to select optimal samples for aGVHD treatment that can improve clinical results. aGVHD treatment with MSCs has shown efficacy comparable to other treatment approaches. Given the low percentage of complications and the absence of significant adverse effects, MSC therapy seems to be one of the optimal approaches to the treatment of resistant forms of GVHD.

Diagnostics and treatment challenges of Ph-like acute lymphoblastic leukemia: a description of 3 clinical cases.

B-cell acute lymphoblastic leukemia (B-ALL) is a diverse group of malignant blood disorders both with regard to the biological properties of the tumor and to therapeutic approaches. Immunophenotyping, molecular genetic techniques, whole-genome sequencing characterize B-ALL as a very diverse group for sensitivity to chemotherapy and prognosis. We present three clinical cases of patients with B-ALL and expected good response to standard therapy, in whom standard protocol treatment failured: refractoriness, persistence of minimal residual disease (MRD), and progression (MRD increase). The remission in these patients was achieved after chemotherapy change to immunological targeted therapy. Nowadays a unified therapeutic approach to all primary patients of the B-ALL is considered generally outdated. Great efforts are carrying out to develop molecular genetic classifications. The molecular dissection of subtypes of B-ALL goes on, and new protocols for selective treatment with targeting are clearly outlined for each subtype of B-ALL.

Effect of Priming of Multipotent Mesenchymal Stromal Cells with Interferon γ on Their Immunomodulating Properties.

Multipotent mesenchymal stromal cells (MSCs) are widely used for cell therapy, in particular for prophylaxis and treatment of graft-versus-host disease. Due to their immunomodulatory properties, MSCs affect the composition of lymphocyte subpopulations, which depends on the immunological state of the organism and can change in different diseases and during treatment. Administration of MSCs is not always effective. Treatment of MSCs with different cytokines (in particular IFN-γ) leads to enhancement of their immunomodulatory properties. The aim of this study was to investigate subpopulational alterations and activation markers in lymphocytes (activated and non-activated) after interaction with MSCs and MSCs pretreated with IFN-γ (γMSCs) in vitro. Lymphocytes were co-cultured with MSCs or γMSCs for 4 days. The proportion of CD4+ and CD8+ expressing CD25, CD38, CD69, HLA-DR, and PD-1 and distribution of memory and effector subsets were measured by flow cytometry after co-cultivation of lymphocytes with MSCs or γMSCs. The distribution of lymphocyte subpopulations changes during culturing. In non-activated lymphocytes cultured without MSCs, decrease in the proportion of naïve cells and increase in the number of effector cells was observed. That could be explained as activation of lymphocytes in the presence of serum in culturing medium. Co-culturing of lymphocytes with MSCs and γMSCs leads to retention of their non-activated state. Activation of lymphocytes with phytohemagglutinin increases the number of central memory cells and activates marker expression. Interaction with MSCs and γMSCs prevents activation of lymphocytes and keeps their naïve state. Priming with IFN-γ did not induce MSCs inhibitory effect on activation of lymphocytes.

Recombinant MHC Tetramers for Isolation of Virus-Specific CD8+ Cells from Healthy Donors: Potential Approach for Cell Therapy of Posttransplant Cytomegalovirus Infection.

Patients undergoing allogeneic hematopoietic stem cell transplantation have a high risk of cytomegalovirus reactivation, which in the absence of T-cell immunity can result in the development of an acute inflammatory reaction and damage of internal organs. Transfusion of the virus-specific donor T-lymphocytes represents an alternative to a highly toxic and often ineffective antiviral therapy. Potentially promising cell therapy approach comprises transfusion of cytotoxic T-lymphocytes, specific to the viral antigens, immediately after their isolation from the donor's blood circulation without any in vitro expansion. Specific T-cells could be separated from potentially alloreactive lymphocytes using recombinant major histocompatibility complex (MHC) multimers, carrying synthetic viral peptides. Rapid transfusion of virus-specific T-cells to patients has several crucial advantages in comparison with methods based on the in vitro expansion of the cells. About 30% of hematopoietic stem cell donors and 46% of transplant recipients at the National Research Center for Hematology were carriers of the HLA-A*02 allele. Moreover, 94% of Russian donors have an immune response against the cytomegalovirus (CMV). Using recombinant HLA-A*02 multimers carrying an immunodominant cytomegalovirus peptide (NLV), we have shown that the majority of healthy donors have pronounced T-cell immunity against this antigen, whereas shortly after the transplantation the patients do not have specific T-lymphocytes. The donor cells have the immune phenotype of memory cells and can be activated and proliferate after stimulation with the specific antigen. Donor lymphocytes can be substantially enriched to significant purity by magnetic separation with recombinant MHC multimers and are not activated upon cocultivation with the antigen-presenting cells from HLA-incompatible donors without addition of the specific antigen. This study demonstrated that strong immune response to CMV of healthy donors and prevalence of HLA-A*02 allele in the Russian population make it possible to isolate a significant number of virus-specific cells using HLA-A*02-NLV multimers. After the transfusion, these cells should protect patients from CMV without development of allogeneic immune response.

Minimal residual disease in multiple myeloma: Benefits of flow cytometry.

Over the last 20 years, the approaches to the treatment of multiple myeloma (MM) have changed considerably, which led to an increase in remission rate. Using new diagnostic methods has made it possible to assess the response to treatment more reliably and forecast disease recurrence: allele-specific polymerase chain reaction, new-generation sequencing and multicolor flow cytometry enable minimal residual disease (MRD) detection of with sensitivity of 10-5 to 10-6 . MRD assessment with flow cytometry using is a rapidly developing area of research. The goal of multicenter groups that use flow cytometry as a tool to detect MRD in patients with MM is achieving standardization and increasing sensitivity and specificity of this method. This article provides data about the methods used for MRD monitoring and describes the advances in the field of flow cytometry.