Kinetics of Recovery of Naïve and Memory T Cells in Acute Leukemia Patients after Allogeneic Stem Cell Transplantation Depending on Different GVHD Prophylaxis Regimens.

Background: Memory T cells are a heterogeneous population of immune cells that provide adaptive immunity. Its full recovery seems essential for graft-versus-tumor reactions that provide an opportunity for biological cure in patients with acute leukemia. The use of mismatched or haploidentical donors has increased, which has become possible because of modifications in graft versus host disease (GVHD) prophylaxis. Materials and Methods: Sixty-five leukemia patients (acute myeloid leukemia - 40, acute lymphoblastic leukemia - 25), median age 33 (17-61) years, underwent allo-HSCT from 2016 to 2019 in the National Research Centre for Hematology. Patients were divided into three groups based on the impact of GVHD prophylaxis on T cell recovery: horse antithymocyte globulin (ATG)-based regimen (n=32), horse ATG combined with posttransplant cyclophosphamide (PT-Cy) (n=18), and ex vivo T cell depletion (n=15). Results: The early period after transplantation (before day +100) was characterized by significantly lower absolute numbers of T naïve, memory stem and T central memory cells in peripheral blood in patients after ATG+PT-Cy-regimen or ex vivo T cell depletion than after ATG-based prophylaxis (p<0.05). Moreover, strong depletion of naïve T and memory stem cells prevents the development of GVHD, and determining the absolute number of CD8+ naïve T and memory stem cells with a cutoff of 1.31 cells per microliter seems to be a perspective in assessing the risks of developing acute GVHD (p=0.008). The dynamics of T cell recovery showed the involvement of either circulating or bone marrow resident T effector cells shortly after allogeneic transplantation in all patients, but the use of manipulated grafts with ex vivo T cell depletion requires the involvement of naïve and memory stem cells. There was no significant effect of T cell recovery on leukemia relapse after allogeneic transplantation. Conclusion: These experimental outcomes contribute to providing the best understanding of immunological events that occur early after transplantation and help in the rational choice of GVHD prophylaxis in patients who will undergo allogeneic transplantation. Our study demonstrated the comparable immunological effects of posttransplant cyclophosphamide and ex vivo T cell depletion and immunological inefficiency of horse ATG for GVHD prevention.

DNA Copy Number Alterations and Copy Neutral Loss of Heterozygosity in Adult Ph-Negative Acute B-Lymphoblastic Leukemia: Focus on the Genes Involved.

The landscape of chromosomal aberrations in the tumor cells of the patients with B-ALL is diverse and can influence the outcome of the disease. Molecular karyotyping at the onset of the disease using chromosomal microarray (CMA) is advisable to identify additional molecular factors associated with the prognosis of the disease. Molecular karyotyping data for 36 patients with Ph-negative B-ALL who received therapy according to the ALL-2016 protocol are presented. We analyzed copy number alterations and their prognostic significance for CDKN2A/B, DMRTA, DOCK8, TP53, SMARCA2, PAX5, XPA, FOXE1, HEMGN, USP45, RUNX1, NF1, IGF2BP1, ERG, TMPRSS2, CRLF2, FGFR3, FLNB, IKZF1, RUNX2, ARID1B, CIP2A, PIK3CA, ATM, RB1, BIRC3, MYC, IKZF3, ETV6, ZNF384, PTPRJ, CCL20, PAX3, MTCH2, TCF3, IKZF2, BTG1, BTG2, RAG1, RAG2, ELK3, SH2B3, EP300, MAP2K2, EBI3, MEF2D, MEF2C, CEBPA, and TBLXR1 genes, choosing t(4;11) and t(7;14) as reference events. Of the 36 patients, only 5 (13.8%) had a normal molecular karyotype, and 31 (86.2%) were found to have various molecular karyotype abnormalities-104 deletions, 90 duplications or amplifications, 29 cases of cnLOH and 7 biallelic/homozygous deletions. We found that 11q22-23 duplication involving the BIRC3, ATM and MLL genes was the most adverse prognostic event in the study cohort.

Acute Myeloid Leukemia Causes Serious and Partially Irreversible Changes in Secretomes of Bone Marrow Multipotent Mesenchymal Stromal Cells.

In patients with acute myeloid leukemia (AML), malignant cells modify the properties of multipotent mesenchymal stromal cells (MSCs), reducing their ability to maintain normal hematopoiesis. The aim of this work was to elucidate the role of MSCs in supporting leukemia cells and the restoration of normal hematopoiesis by analyzing ex vivo MSC secretomes at the onset of AML and in remission. The study included MSCs obtained from the bone marrow of 13 AML patients and 21 healthy donors. The analysis of proteins contained in the MSCs-conditioned medium demonstrated that secretomes of patient MSCs differed little between the onset of AML and remission; pronounced differences were observed between MSC secretomes of AML patients and healthy donors. The onset of AML was accompanied by a decrease in the secretion of proteins related to ossification, transport, and immune response. In remission, but not at the onset, secretion of proteins responsible for cell adhesion, immune response, and complement was reduced compared to donors. We conclude that AML causes crucial and, to a large extent, irreversible changes in the secretome of bone marrow MSCs ex vivo. In remission, functions of MSCs remain impaired despite the absence of tumor cells and the formation of benign hematopoietic cells.

Clinical Outcomes in Patients With COVID-19 and Hematologic Disease.

BACKGROUND: Patients with hematologic diseases are at higher risk of the SARS-CoV-2 infection and more severe clinical outcomes of the coronavirus disease. CHRONOS19 is an observational prospective cohort study with the aim to determine the short and longer-term clinical outcomes, risk factors for disease severity and mortality, and rates of postinfectious immunity in patients with malignant and nonmalignant hematologic diseases and COVID-19. PATIENTS AND METHODS: Overall, 666 patients were enrolled in the study, of which 626 were included in the final data analysis. The primary endpoint was 30-days all-cause mortality. Secondary endpoints included COVID-19 complications, rates of ICU admission and mechanical ventilation, outcomes of a hematologic disease in SARS-CoV-2 infected patients, overall survival, and risk factors for disease severity and mortality. Data from 15 centers were collected at 30, 90, and 180 days after COVID-19 was diagnosed and were managed using a web-based e-data capture platform. All evaluations were performed in the pre-omicron period of COVID-19 pandemic. RESULTS: Thirty-days all-cause mortality was 18.9%. The predominant cause of death (in 80% of cases) were COVID-19 complications. At 180 days, the majority (70%) of additional deaths were due to hematologic disease progression. At a median follow-up of 5.7 [0.03-19.04] months, 6-months overall survival was 72% [95% CI: 0.69-0.76]. One-third of patients had severe SARS-CoV-2 disease. The rate of ICU admission was 22% with 77% of these patients requiring mechanical ventilation, with poor survival rate. A univariate analysis revealed that older age (≥ 60 years), male sex, malignant hematologic disease, myelotoxic agranulocytosis, transfusion dependence, refractory disease or relapse, diabetes among comorbidities, any complications, especially ARDS alone or in combination with CRS, admission to an ICU, and mechanical ventilation were associated with higher risks of mortality. Treatment of the hematologic disease was changed, postponed, or canceled in 63% of patients. At a longer follow-up (90 and 180 days), the status of the hematologic disease changed in 7.5% of patients. CONCLUSION: Patients with hematologic disease and COVID-19 have high mortality rates, predominantly due to COVID-19 complications. At a longer-term follow-up, no significant impact of COVID-19 on the course of a hematologic disease was revealed.

Long-term outcome of second allogeneic hematopoietic stem cell transplantation (HSCT2) for primary graft failure in patients with acute leukemia in remission: A study on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

Second transplantation (HSCT2) is a potential treatment for primary graft failure (pGF). We assessed the outcome of HSCT2, performed between 2000 and 2021, for pGF in 243 patients with acute leukemia. Median age was 44.8 years. Conditioning at first HSCT (HSCT1) was myeloablative (MAC) in 58.4%. Median time from HSCT1 to HSCT2 was 48 days. Donors for HSCT2 were the same as for HSCT1 in 49%. Engraftment post HSCT2 was achieved by 73.7% of patients. The incidence of acute (a) graft versus host disease (GVHD) grades II-IV and III-IV was 23.2 and 8.1%. 5-year total and extensive chronic (c) GVHD was 22.3 and 10.1%. 5-year nonrelapse mortality (NRM), relapse incidence (RI), leukemia-free survival (LFS), overall survival (OS) and GVHD free, relapse-free survival (GRFS) was 51.6, 18.8, 29.6, 30.7 and 22.4%, respectively. Infections were the main cause of death. In multivariable analysis, being transplanted at second vs. first remission, lower Karnofsky performance status (KPS; <90) and receiving MAC at HSCT1 were adverse prognostic factors for NRM, LFS, OS, and GRFS, as was increased age for NRM, LFS, OS. We conclude that HSCT2 can rescue about a third of the patients who experienced pGF, but NRM is as high as 50%.

Post-engraftment Bloodstream Infections After Allogeneic Hematopoietic Cell Transplantation: Risk Factors and Association with Mortality.

BACKGROUND: Bloodstream infections (BSIs) are major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (allo-HCT). This study aimed to analyze the incidence, etiology, risk factors and outcomes of post-engraftment BSI in allo-HCT recipients. MATERIALS AND METHODS: The retrospective study included 261 patients with documented engraftment after first allo-HCT performed from January 2018 till September 2021. RESULTS: Of 261 patients 29 (11.1%) developed at least one post-engraftment BSIs episode with a median time to post-engraftment BSI of 49 days (range, 1 - 158 days from the engraftment). A total of 45 pathogens were isolated from blood - 64.4% (n = 29) were represented by Gram-negative bacteria, and 35.6% (n = 16) - by Gram-positive bacteria. Secondary graft failure (hazard ratio [HR]: 39.93; 95% confidence interval [CI]: 7.64-208.74; P <0.001), secondary poor graft function (HR: 18.07; 95% CI: 3.53 - 92.44; P <0.001), and acute gut graft-versus-host-disease (GvHD) grade II-IV (HR: 29.86; 95% CI: 10.53 - 84.68; P <0.001) were associated with the higher risk of Gram-negative post-engraftment BSIs. Overall 30-day survival after post-engraftment BSIs was 71.4%. By multivariate analysis post-engraftment BSIs (HR: 3.09; 95% CI: 1.29 - 7.38; P = 0.011), and acute gut GvHD grade II-IV (HR: 6.60; 95% CI: 2.78 - 15.68; P <0.001) were associated with the higher 180-day non-relapse mortality risk. CONCLUSION: Gram-negative bacteria prevailed in the etiology of post-engraftment BSIs with secondary graft failure. secondary poor graft function. and acute gut GvHD being the main predisposing factors for their development. Post-engraftment BSIs were associated with the higher risk of non-relapse mortality after allo-HCT.

Impact of fluoroquinolone administration and gut mucosal colonization on the risk of pre-engraftment bloodstream infections after allogeneic hematopoietic cell transplantation.

Fluoroquinolones (FQ) has been used after allogeneic hematopoietic stem cell transplantation (allo-HCT) for decades. This study on 284 allo-HCT recipients aimed to analyze the impact of FQ on pre-engraftment BSI. A total of 154 patients were colonized with resistant gram-negative bacteria, and 130 patients were not. Colonized patients did not receive FQ (n = 147) except 7 who received FQ as sequential therapy; 98 non-colonized patients received FQ, whereas 32 did not. Gram-negative (p < 0.0001), and ESBL-E BSI (p < 0.0001) were higher in colonized patients receiving FQ. No difference was found in gram-positive BSI (p = 0.452). In multivariate analysis colonized patients with (p < 0.0001) or without FQ (p = 0.007), omission of FQ in non-colonized patients (p = 0.038), and active disease (p = 0.042) were associated with gram-negative BSI, whereas mismatched unrelated donor transplantations - with gram-positive BSI (p = 0.009). Colonized patients with FQ have a higher risk of gram-negative BSI. In non-colonized patients, FQ prophylaxis is effective approach significantly reducing gram-negative BSI risk.

Recurrent bloodstream infections after allogeneic hematopoietic cell transplantation.

BACKGROUND: Although colonization is an established risk factor for bloodstream infection (BSI) due to identical strain, prior infection with resistant bacteria should also be considered during the management of febrile neutropenia. This study aimed to analyze the rate and etiology of recurrent BSI in allogeneic hematopoietic cell transplant (allo-HCT) recipients to determine its potential impact on decision-making. MATERIALS AND METHODS: The retrospective study included 284 allo-HCT recipients. Recurrent BSI was defined as a new BSI episode occurring in a period of more than 72 hours after antibiotic withdrawal. RESULTS: Overall, 104 patients (36.6%) developed at least one BSI, and 23 of them (22.1%) experienced recurrent BSI episodes (n = 30). Median time to recurrent BSI was 41 days (range 5-526 days). Recurrent BSI was associated with second allo-HCT (p < 0.0001), primary (p = 0.021), and secondary graft failure (p = 0.024). Carbapenem-resistant gram-negative bacteria were more common during recurrent BSI episodes (23.7% vs. 6.0%; p = 0.003). In only 17.5% patients experiencing recurrent BSI episode and in only 3.9% of patients with at least one BSI episode phenotypically identical recurring pathogen was isolated. CONCLUSIONS: In view of low rate of recurrent BSI due to identical pathogen, empirical antimicrobial therapy should not be based on data on previous BSI episodes.

T Cell and Cytokine Dynamics in the Blood of Patients after Hematopoietic Stem Cell Transplantation and Multipotent Mesenchymal Stromal Cell Administration.

Multipotent mesenchymal stromal cells (MSCs) are currently under intensive investigation for the treatment and prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), owing to their substantial immunomodulatory properties. The responses of recipients to MSC infusion following allo-HSCT are not yet well understood. T cells are central to the adaptive immune system, protecting the organism from infection and malignant cells. Memory T cells with different phenotypes, gene expression profiles, and functional properties are critical for immune processes regulation. The aim of this study was to study the dynamics of memory T cell subpopulations and cytokines in the blood of allo-HSCT recipients after MSC administration. In clinical trial NCT01941394, patients after allo-HSCT were randomized into 2 groups, one receiving standard GVHD prophylaxis and the other also receiving MSC infusion on the day of leukocyte recovery to 1000 cells/µL (engraftment, day E0). Blood samples of patients from both groups were analyzed on days E0, E+3, and E+30. T cell subpopulations were studied by flow cytometry, and cytokine concentrations were evaluated by the Bio-Plex Pro Human Cytokine Panel. Administration of MSCs to patients on day E0 did not affect the overall dynamics of restoration of absolute numbers and proportions of T and B lymphocytes after 3 and 30 days. At 3 days after MSC injection, only the numbers of CD8+ effector cells (CD8+TE, CD8+TM, and CD8+EM) were found to increase significantly. A significant increase in the number of CD4+ cells after 30 days compared to day E0 was observed only in patients who received MSCs, indicating faster recovery of the CD4+ cell population following MSC injection. An increase in CD8+ cell number by day E+30 was significant regardless of MSC administration. To characterize the immune status of patients following allo-HSCT in more detail, changes in the cytokine concentration in the peripheral blood of patients on days E0, E+3, and E+30 after MSC administration were investigated. On day E+30, significant increases in the numbers of CD4+CM and activated CD4+CD25+ cells were observed. The concentrations of proinflammatory and anti-inflammatory cytokines IL-6, IL-8, IL-17, TNF-α, and IFN-γ were increased significantly in patients injected with MSCs. Analysis of growth factor levels showed that in the group of patients who received MSCs, the concentrations of G-CSF, GM-CSF, PDGFbb, FGFb, and IL-5 increased by day E+30. Among the cytokines involved in regulation of the immune response, concentrations of IL-9, eotaxin, IP-10, MCP-1, and MIP-1a were increased after 30 days irrespective of MSC administration. The administration of MSCs exerts a positive effect on the restoration of T cell subpopulations and immune system recovery in patients after allo-HSCT.

Characterization of four new HLA alleles: HLA-A*68:288, -C*07:1012, -C*13:364, and -DQA1*05:51.

Four new alleles HLA-A*68:288, C*07:1012, C*12:364, and DQA1*05:51 discovered in Russian individuals.

Incidence, etiology, risk factors, and outcomes of pre-engraftment bloodstream infections after first and second allogeneic hematopoietic cell transplantation.

INTRODUCTION: With an increasing number of allogeneic hematopoietic cell transplantations (allo-HCT) bloodstream infections (BSI) are still among the most common and serious complications. This study aimed to analyze the incidence, etiology, risk factors, and outcomes of pre-engraftment BSI after the first and the second allo-HCT. MATERIALS AND METHODS: This is a retrospective study of 284 patients who underwent the first allo-HCT and 37 patients after the second allo-HCT at the National Research Center for Hematology in Moscow, Russia, from January 2018 till September 2021. RESULTS: Cumulative incidence of pre-engraftment BSI was 29.9% after the first allo-HCT and 35.1% after the second (p = .805). The median time to the first BSI was 9 days (range 0-61 days) after the first and 16 days (range 1-28 days) after the second allo-HCT (p = .014). A total of 113 pathogens were isolated during 94 BSI episodes after the first allo-HCT (gram-negative bacteria 52.2%; gram-positive bacteria 47.7%). Fourteen pathogens were isolated during 14 BSI episodes after the second allo-HCT (gram-negative bacteria 50.0%; gram-positive bacteria 50.0%). The only significant difference was found in the rate of carbapenem-resistant gram-negative bacteria, which was higher after the second allo-HCT compared to the first (57.1% vs. 13.6%; p = .048). Mismatched unrelated donor (hazards ratio [HR] 3.01; 95% confidence interval [CI]: 1.62-5.60; p < .0001) and haploidentical donor transplantations (HR 1.84; 95% CI: 1.02-3.33; p = .042) were the only independent risk factors associated with the higher risk of pre-engraftment BSI. Overall 30-day survival after all BSI episodes was 94.4%. Survival was lower after BSI during the second allo-HCT compared to the first (71.4% vs. 97.9%; p < .0001), particularly after BSI was caused by carbapenem-resistant gram-negative bacteria (25.0% vs. 100.0%; p = .0023). The non-relapse mortality rate at day +60 was 4.0%, and the risk was highly associated with primary graft failure (HR 9.62; 95% CI: 1.33-71.43), second allo-HCT (HR 6.80; 95% CI: 1.36-34.48), and pre-engraftment BSI caused by carbapenem-resistant gram-negative bacteria (HR 32.11; 95% CI: 4.91-210.15). CONCLUSIONS: Pre-engraftment BSI is still a common complication after allo-HCT, particularly after mismatched unrelated and haploidentical donor transplantations. BSI incidence was slightly higher after the second allo-HCT with a significantly higher rate of carbapenem-resistant BSI. Although pre-engraftment BSI would generally follow a benign clinical course, survival was dramatically lower during the second allo-HCT, especially after carbapenem-resistant BSI.

Loss of Heterozygosity in the Tumor DNA of De Novo Diagnosed Patients Is Associated with Poor Outcome for B-ALL but Not for T-ALL.

Despite the introduction of new technologies in molecular diagnostics, one should not underestimate the traditional routine methods for studying tumor DNA. Here we present the evidence that short tandem repeat (STR) profiling of tumor DNA relative to DNA from healthy cells might identify chromosomal aberrations affecting therapy outcome. Tumor STR profiles of 87 adult patients with de novo Ph-negative ALL (40 B-ALL, 43 T-ALL, 4 mixed phenotype acute leukemia (MPAL)) treated according to the "RALL-2016" regimen were analyzed. DNA of tumor cells was isolated from patient bone marrow samples taken at diagnosis. Control DNA samples were taken from the buccal swab or the blood of patients in complete remission. Overall survival (OS) analysis was used to assess the independent impact of the LOH as a risk factor. Of the 87 patients, 21 were found with LOH in various STR loci (24%). For B-ALL patients, LOH (except 12p LOH) was an independent risk factor (OS hazard ratio 3.89, log-rank p-value 0.0395). In contrast, for T-ALL patients, the OS hazard ratio was 0.59 (log-rank p-value 0.62). LOH in particular STR loci measured at the onset of the disease could be used as a prognostic factor for poor outcome in B-ALL, but not in T-ALL.

Bowel wall thickness is a strong predictor of steroid-refractory acute graft-versus-host disease with gut involvement after allo-HSCT.

OBJECTIVE: Acute graft-versus-host-disease (aGVHD) develops in 10-80% of allo-HSCT patients. More than half of all aGVHD cases are refractory to first-line therapy with steroids. We hypothesized that bowel wall thickness at the time of aGVHD diagnosis could be an early sign of steroid-refractory aGVHD with gut involvement. METHOD: Our prospective study included 85 patients with hematological malignancies who had undergone allo-HSCT. We used an inexpensive, widespread and simple method of transabdominal ultrasonography to examine bowel wall thickness in patients suspected to have gut aGVHD. RESULTS: Descending colon wall thickness was significantly greater in patients with gut aGVHD later found to be steroid-refractory than in patients with steroid-sensitive gut aGVHD, with AUC-0.73 (95% CI 0.58-0.87, p = 0.013). We showed that bowel wall thickness could predict the steroid-refractoriness of aGVHD. CONCLUSION: Transabdominal ultrasonography could be used as a marker of steroid-refractory aGVHD with gut involvement after allo-HSCT.

Immunophenotype of Measurable Residual Blast Cells as an Additional Prognostic Factor in Adults with B-Cell Acute Lymphoblastic Leukemia.

Measurable residual disease (MRD) is a well-known independent prognostic factor in acute leukemias, and multicolor flow cytometry (MFC) is widely used to detect MRD. MFC is able not only to enumerate MRD accurately but also to describe an antigen expression profile of residual blast cells. However, the relationship between MRD immunophenotype and patient survival probability has not yet been studied. We determined the prognostic impact of MRD immunophenotype in adults with B-cell acute lymphoblastic leukemia (B-ALL). In a multicenter study RALL-2016 (NCT03462095), 267 patients were enrolled from 2016 to 2022. MRD was assessed at the end of induction (day 70) in 94 patients with B-ALL by six- or 10-color flow cytometry in the bone marrow specimens. The 4 year relapse-free survival (RFS) was lower in MRD-positive B-ALL patients [37% vs. 78% (p < 0.0001)]. The absence of CD10, positive expression of CD38, and high expression of CD58 on MRD cells worsened the 4 year RFS [19% vs. 51% (p = 0.004), 0% vs. 51% (p < 0.0001), and 21% vs. 40% (p = 0.02), respectively]. The MRD immunophenotype is associated with RFS and could be an additional prognostic factor for B-ALL patients.

The outcome of Ph-negative acute lymphoblastic leukemia presenting during pregnancy and treated on the Russian prospective multicenter trial RALL-2009.

We report the data on 15 women who presented with Ph-negative acute lymphoblastic leukemia (ALL) between Jan 2009 until Dec 2016 and who were treated on the prospective multicenter RALL-2009 clinical trial. A comparison of their outcome was made with 129 non-pregnant females who entered the study and were treated by the same schedule. 10-years OS for pregnant and non-pregnant women was 58.6 % (29.6 %-85.0 %) and 43.3 % (32.1 %-58.8 %), DFS was 46 % (15.2 %-78.8 %) and 51 % (39.7 %-64.6 %); probability of relapse was 49 % (16.6 %-83.3 %) and 40.3 % (27.3 %-53.4 %), respectively. Twelve born during the study children are well and alive with a median age 5 years 2 months (2 years - 9 years). Though small, our study has shown some specific features of ALL diagnosed during pregnancy (more T-cell ALL, higher initial WBC, later responses) and has shown that the long-term outcome of women with ALL treated while pregnant is equivalent to female control patients treated on the same protocol.

High expression of granzyme B in conventional CD4+ T cells is associated with increased relapses after allogeneic stem cells transplantation in patients with hematological malignancies.

Granzyme B is known to be a serine protease contained in granules of cytotoxic T cells. We have previously reported an influence of granzyme B expression in T regulatory cells (Tregs) on the risk of acute graft versus host disease (GVHD) onset. However, it is still unknown if conventional T cells (Tcon) use the granzyme B pathway as a mechanism of alloimmunity. We hypothesized that granzyme B in Tcon may affect recurrence within the first 6 months after allogeneic transplantation (allo-HSCT). A total of 65 patients with different hematological malignancies were included in this study. Blood samples were collected on day +30 after allo-HSCT. The percentage of granzyme B positive conventional T cells in patients who developed relapse in the first 6 months after allo-HSCT was 11.3 (4.5-35.3) compared to the others in continuous complete remission-1.3 (3.65-9.7), р = 0.011. The risk of relapse after allo-HSCT was in 3.9 times higher in patients with an increased percentage of granzyme B positive conventional T cells. The findings demonstrated that the percentage of granzyme B positive conventional T cells on day +30 after allo-HSCT could be a predictable marker of relapse within the first 6 months after allo-HSCT.

Diagnostic significance of flow cytometry scales in diagnostics of myelodysplastic syndromes.

BACKGROUND: Myelodysplastic syndromes (MDS) can present a challenge for clinicians. Multicolor flow cytometry (MFC) can aid in establishing a diagnosis. The aim of this study was to determine the optimal MFC approach for MDS. METHODS: The study included 102 MDS (39 low-grade MDS), 83 cytopenic patients without myeloid neoplastic disorders (control group), and 35 healthy donors. Bone marrow was analyzed using a six-color MFC. Analysis was conducted according to the "Ogata score," "Wells score," and the integrated flow cytometry (iFC) score. RESULTS: The respective sensitivity and specificity values were 77.5% and 90.4% for the Ogata score, 79.4% and 81.9% for the Wells score, and 87.3% and 87.6% for the iFC score. Specificity was not 100% due to deviations of MFC parameters in the control group. Patients with paroxysmal nocturnal hemoglobinuria (PNH) had higher levels of CD34+ CD7+ myeloid cells than donors. Aplastic anemia and PNH were characterized by a high proportion of CD56+ cells among CD34+ precursors and neutrophils. The proportion of MDS-related features increased with the progression of MDS. The highest number of CD34+ blasts was found in MDS with excess blasts. MDS with isolated del(5q) was characterized by a high proportion of CD34+ CD7+ cells and low granularity of neutrophils. In 39 low-grade MDS, the sensitivities were 53.8%, 61.5%, and 71.8% for Ogata score, Wells score, and iFC, respectively. CONCLUSION: The results support iFC as a useful diagnostic tool in MDS.

Immunophenotypic characteristics of multipotent mesenchymal stromal cells that affect the efficacy of their use in the prevention of acute graft vs host disease.

BACKGROUND: Multipotent mesenchymal stromal cells (MSCs) are widely used in the clinic due to their unique properties, namely, their ability to differentiate in all mesenchymal directions and their immunomodulatory activity. Healthy donor MSCs were used to prevent the development of acute graft vs host disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT). The administration of MSCs to patients was not always effective. The MSCs obtained from different donors have individual characteristics. The differences between MSC samples may affect their clinical efficacy. AIM: To study the differences between effective and ineffective MSCs. METHODS: MSCs derived from the bone marrow of a hematopoietic stem cells donor were injected intravenously into allo-BMT recipients for GVHD prophylaxis at the moment of blood cell reconstitution. Aliquots of 52 MSC samples that were administered to patients were examined, and the same cells were cultured in the presence of peripheral blood mononuclear cells (PBMCs) from a third-party donor or treated with the pro-inflammatory cytokines IL-1ß, IFN and TNF. Flow cytometry revealed the immunophenotype of the nontreated MSCs, the MSCs cocultured with PBMCs for 4 d and the MSCs exposed to cytokines. The proportions of CD25-, CD146-, CD69-, HLA-DR- and PD-1-positive CD4+ and CD8+ cells and the distribution of various effector and memory cell subpopulations in the PBMCs cocultured with the MSCs were also determined. RESULTS: Differences in the immunophenotypes of effective and ineffective MSCs were observed. In the effective samples, the mean fluorescence intensity (MFI) of HLA-ABC, HLA-DR, CD105, and CD146 was significantly higher. After MSCs were treated with IFN or cocultured with PBMCs, the HLA-ABC, HLA-DR, CD90 and CD54 MFI showed a stronger increase in the effective MSCs, which indicated an increase in the immunomodulatory activity of these cells. When PBMCs were cocultured with effective MSCs, the proportions of CD4+ and CD8+central memory cells significantly decreased, and the proportion of CD8+CD146+ lymphocytes increased more than in the subpopulations of lymphocytes cocultured with MSC samples that were ineffective in the prevention of GVHD; in addition, the proportion of CD8+effector memory lymphocytes decreased in the PBMCs cocultured with the effective MSC samples but increased in the PBMCs cocultured with the ineffective MSC samples. The proportion of CD4+CD146+ lymphocytes increased only when cocultured with the inefficient samples. CONCLUSION: For the first time, differences were observed between MSC samples that were effective for GVHD prophylaxis and those that were ineffective. Thus, it was shown that the immunomodulatory activity of MSCs depends on the individual characteristics of the MSC population.

Blinatumomab vs historic standard-of-care treatment for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukaemia.

OBJECTIVES: Survival outcomes from a single-arm phase 2 blinatumomab study in patients with minimal residual disease (MRD)-positive B-cell precursor (BCP)-acute lymphoblastic leukaemia (ALL) were compared with those receiving standard of care (SOC) in a historic data set. METHODS: The primary analysis comprised adult Philadelphia chromosome (Ph)-negative patients in first complete haematologic remission (MRD ≥ 10-3 ). Relapse-free survival (RFS) and overall survival (OS) were compared between blinatumomab- and SOC-treatment groups. Baseline differences between groups were adjusted by propensity scores. RESULTS: The primary analysis included 73 and 182 patients from the blinatumomab and historic data sets, respectively. When weighted by age to the blinatumomab-treatment group, median RFS was 7.8 months and median OS was 25.9 months in the SOC-treated group. In the blinatumomab study, median RFS was 35.2 months; median OS was not evaluable. Propensity score weighting achieved balance with seven baseline prognostic factors. With adjustment for haematopoietic stem cell transplantation (HSCT) status, a 50% reduction in risk of relapse or death was observed with blinatumomab vs SOC. Median RFS, unadjusted for HSCT status, was 35.2 months with blinatumomab and 8.3 months with SOC. CONCLUSIONS: These analyses suggest that blinatumomab improves RFS, and possibly OS, in adults with MRD-positive Ph-negative BCP-ALL vs SOC.