Search

The association between mature B-cell phenotype and KMT2A rearrangements in acute lymphoblastic leukemia is a very rare finding. It identifies a group of patients with similar clinical and biologic...

PurposePatients with Fanconi anaemia (FA), a rare DNA repair genetic disease, exhibit chromosome fragility, bone marrow failure, malformations and cancer susceptibility. FA molecular diagnosis is challenging since FA is caused by point mutations and large deletions in 22 genes following three heritability patterns. To optimise FA patients’ characterisation, we developed a simplified but effective methodology based on whole exome sequencing (WES) and functional studies.Methods68 patients with FA were analysed by commercial WES services. Copy number variations were evaluated by sequencing data analysis with RStudio. To test FANCA missense variants, wt FANCA cDNA was cloned and variants were introduced by site-directed mutagenesis. Vectors were then tested for their ability to complement DNA repair defects of a FANCA-KO human cell line generated by TALEN technologies.ResultsWe identified 93.3% of mutated alleles including large deletions. We determined the pathogenicity of three FANCA missense variants and demonstrated that two FANCA variants reported in mutations databases as ‘affecting functions’ are SNPs. Deep analysis of sequencing data revealed patients’ true mutations, highlighting the importance of functional analysis. In one patient, no pathogenic variant could be identified in any of the 22 known FA genes, and in seven patients, only one deleterious variant could be identified (three patients each with FANCA and FANCD2 and one patient with FANCE mutations)ConclusionWES and proper bioinformatics analysis are sufficient to effectively characterise patients with FA regardless of the rarity of their complementation group, type of mutations, mosaic condition and DNA source.

The association between mature B-cell phenotype and

[Background]: Telomeres are nucleoprotein structures present at the terminal region of the chromosomes. Mutations in genes coding for proteins involved in telomere maintenance are causative of a number of disorders known as telomeropathies. The genetic origin of these diseases is heterogeneous and has not been determined for a significant proportion of patients., [Methods]: This article describes the genetic characterization of a cohort of patients. Telomere length was determined by Southern blot and quantitative PCR. Nucleotide variants were analyzed either by high-resolution melting analysis and Sanger sequencing of selected exons or by massive sequencing of a panel of genes., [Results]: Forty-seven patients with telomere length below the 10% of normal population, affected with three telomeropathies: dyskeratosis congenita (4), aplastic anemia (22) or pulmonary fibrosis (21) were analyzed. Eighteen of these patients presented known pathogenic or novel possibly pathogenic variants in the telomere-related genes TERT, TERC, RTEL1, CTC1 and ACD. In addition, the analyses of a panel of 188 genes related to haematological disorders indicated that a relevant proportion of the patients (up to 35%) presented rare variants in genes related to DNA repair or in genes coding for proteins involved in the resolution of complex DNA structures, that participate in telomere replication. Mutations in some of these genes are causative of several syndromes previously associated to telomere shortening., [Conclusion]: Novel variants in telomere, DNA repair and replication genes are described that might indicate the contribution of variants in these genes to the development of telomeropathies. Patients carrying variants in telomere-related genes presented worse evolution after diagnosis than the rest of patients analyzed., Funded by grants PI14–01495 and PI17–01401 (Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, Spain supported by FEDER funds) and by one ACCI project from CIBERER and one grant to the FPI cohort from CIBERES., We acknowledge support of the publication fee by the CSIC Open Access Publication Support initiative through its Unit of Information Resources for Research (URICI).

Immune reconstitution is crucial to the success of allogeneic hematopoietic stem cell transplantation. Umbilical cord blood transplantation (UCBT) has been associated with delayed immune reconstitution. We characterized the kinetics and investigated the risk variables affecting recovery of the main lymphocyte subsets in 225 consecutive pediatric and adult patients (males, n = 126; median age, 15; range, .3 to 60; interquartile range, 4 to 35) who underwent myeloablative single UCBT between 2005 and 2015 for malignant and non-malignant disorders. Low CD4(+) and CD8(+) T cell counts were observed up to 12 months after UCBT. In contrast, B and natural killer cells recovered rapidly early after transplantation. In a multivariate regression model, factors favoring CD4(divided by) T cell recovery >= 200 cells/mu L were lower dose antithymocyte globulin (ATG) (hazard ratio [HR], 3.93; 95% confidence interval [CI], 2.3 to 5.83; P=.001), negative recipient cytomegalovirus (CMV) serostatus (HR, 3.76; 95% CI, 1.9 to 5.74; P=.001), and younger age (HR, 2.61; 95% CI, 1.01 to 3.47; P =.03). Factors favoring CD8(divided by) T cell recovery >= 200 cells/mu L were lower dose ATG (HR, 3.03; 95% CI, 1.4 to 5.1; P=.03) and negative recipient CMV serostatus (HR, 1.9; 95% CI, 1.63 to 2.15; P=.01). Our results demonstrate the significant negative impact of ATG on lymphocyte recovery. A reduction of the dose or omission of ATG could improve immune reconstitution and perhaps reduce opportunistic infections after UCBT. (c) 2017 American Society for Blood and Marrow Transplantation.

The authors report the results of 58 children with ALL in 2CR after related (n = 31) or unrelated (n = 27) AHSCT. Characteristics at diagnosis and initial and after relapse antileukemic treatment were similar in the related donor (RD) and the unrelated donor (UD) groups. Conditioning consisted of TBI/CY +/- VP-16 for patients > or = 3 years old (n = 43) and Bu/CY for the rest. Median recipient age was 8 years (range 1-17) in the RD and 9 years (range 3-14) in the UD group. Median follow-up was 54 months (range 24-80) and 52 months (range 22-85) in the RD and the UD groups repectively. The 5-year EFS probability was 43 +/- 9% for the RD group and 36 +/- 9% in the UD group (p = .25). The transplant-related mortality was 16% in the RD and 37% in the UD group (p = .016). In the RD group 36.7% of patients relapsed versus 18.6% in the UD group (p = .05). GvHD associated with organ failure or infection caused most of the transplant-related deaths in both groups. Survivor quality of life for both groups was good (Lansky score < or = 90).

Although high absolute lymphocyte count (ALC) early after transplantation is a simple surrogate for immune reconstitution, few studies to date have established the predictive factors for ALC after umbilical cord blood transplantation (UCBT). We retrospectively studied the factors associated with early lymphocyte recovery and the impact of the ALC on day +42 (ALC42) of ≥300 × 10(6)/L on outcomes in 210 consecutive pediatric and adult patients (112 males; median age, 15 years; range, 0.3 to 60 years; interquartile range, 4 to 36 years) who underwent myeloablative in vivo T cell-depleted single UCBT between 2005 and 2014 for malignant and nonmalignant disorders. In a logistic multivariate regression model, factors favoring a higher ALC42 were higher infused CD3(+) cell dose (odds ratio [OR], 2.7; 95% CI, 1.4 to 5.2; P = .004), lower antithymocyte globulin dose (OR, 2.3; 95% CI, 1.2 to 4.5; P = .01), and better HLA match (OR, 2.1; 95% CI, 1.1 to 4.1; P = .03). In multivariate analysis, lower ALC42 was associated with higher nonrelapse mortality (hazard ratio [HR], 1.76; 95% CI, 1.34 to 2.32; P = .001), whereas a higher ALC42 was associated with better disease-free survival (HR, 2.03; 95% CI, 1.15 to 3.6; P .001) and overall survival (HR, 2.03; 95% CI, 1.17 to 3.6; P .001). Our study suggests that the selection of better HLA-matched cord blood units containing higher CD3(+) cell counts and the use of conditioning regimens with lower ATG doses could improve immune reconstitution after UCBT.

Graft dilution and DMSO washing before cord blood (CB) administration using an automated system may offer low incidence of adverse infusion events (AIE), ensuring reproducible cell yields. Hence, we analyzed the incidences and significance of immediate AIE, cellular yield, and engraftment after single CB infusion. One hundred and fifty-seven patients (median age, 20 years; range, 1 to 60) received a single CB unit for treatment of hematologic and nonhematologic malignancies with myeloablative conditioning after graft dilution and washing. The median total nucleated cell (TNC) doses was 3.4 x 10(7)/kg (range, 2 to 26) and the median post-thaw recovery was 84% (range, 45 to 178). The cumulative incidence of neutrophil engraftment at 50 days was 84% (95% confidence interval [CI], 83 to 93). A total of 118 immediate AIE were observed in fifty-two (33%) patients. All reported AIE were transient, graded from 1 to 2 by Common Terminology Adverse Events version 4. The most frequent toxicity was cardiovascular but without any life-threatening reaction. Infused TNC, recipient's weight, and rate of infusion per kilogram were risk factors associated with cardiovascular AIE in multivariate analysis (odds ratio [OR], 1.2 (95% CI, 1.1 to 1.4); P < .001; OR, .94 (95% CI, .9 to .97); P < .001; and OR, 1.5 (95% Cl, 1.2 to 1.8); P < .001; respectively). In summary, use of an automated method for graft washing before CB administration showed low incidence of AIE without compromising cell yields and engraftment. Infused TNC dose, recipient's weight, and rate of infusion per kilogram were risk factors associated with infusion reactions. (C) 2015 American Society for Blood and Marrow Transplantation.

Introduction: Experience with the use of allogeneic hemopoietic stem transplantation (AHSCT) in pediatric myelodisplastic syndrome (MDS) in Spain is reviewed. Methods and patients: Twenty-four children with MDS were analyzed retrospectively. Median age of the patients was 10 years. Twenty patients received a bone marrow graft and 4 an unrelated cord blood (UCB) transplant; 12 bone marrow grafts were from a matched related donor (MRD) and 8 from a matched unrelated donor (MUD). Conditioning regimen consisted of chemotherapy alone in 17 patients (busulfan and cyclophosphamide +/- melfalan) Seven patients received TBI and cyclophosphamide. Results: Ten patients died from transplant-related toxicity and 4 had relapse or disease progression post-AHSCT. Nine patients are alive and event-free with a median follow-up of 120 months. EFS rate in the MRD group was 0.48 (SE 0.13) versus 0.25 (SE 0.12) in the MUD/UCB group (p = .07). Lansky score in survivors is epsilon 90%. Conclusions: In this historical series of children with MDS, in spite of severe transplant-related toxicity, encouraging EFS outcomes have been achieved after AHSCT with good quality of life.

Previous clinical trials based on the genetic correction of purified CD34(+) cells with gamma-retroviral vectors have demonstrated clinical efficacy in different monogenic diseases, including X-linked severe combined immunodeficiency, adenosine deaminase deficient severe combined immunodeficiency and chronic granulomatous disease. Similar protocols, however, failed to engraft Fanconi anemia (FA) patients with genetically corrected cells. In this study, we first aimed to correlate the hematological status of 27 FA patients with CD34(+) cell values determined in their bone marrow (BM). Strikingly, no correlation between these parameters was observed, although good correlations were obtained when numbers of colony-forming cells (CFCs) were considered. Based on these results, and because purified FA CD34(+) cells might have suboptimal repopulating properties, we investigated the possibility of genetically correcting unselected BM samples from FA patients. Our data show that the lentiviral transduction of unselected FA BM cells mediates an efficient phenotypic correction of hematopoietic progenitor cells and also of CD34(-) mesenchymal stromal cells (MSCs), with a reported role in hematopoietic engraftment. Our results suggest that gene therapy protocols appropriate for the treatment of different monogenic diseases may not be adequate for stem cell diseases like FA. We propose a new approach for the gene therapy of FA based on the rapid transduction of unselected hematopoietic grafts with lentiviral vectors (LVs).

Autologous bone marrow transplantation with monoclonal antibody purged marrow for children with acute lymphoblastic leukemia in second remission