Blood

Unintentional transduction of B-ALL cells during CART19 manufacturing can lead to CAR19+ leukemic cells (CARB19) that are resistant to CART19. We developed an anti-CAR19 idiotype chimeric antigen receptor (αCAR19) to specifically recognize CAR19+ cells. αCAR19 CAR T cells efficiently lysed CARB19 cells in vitro and in a primary leukemia-derived xenograft model. We furthermore demonstrated that αCAR19-CART cells could be used as an "antidote" to deplete CART19 cells to reduce long-term side effects...

Allogeneic stem cell transplantation remains a cornerstone of curative therapy for high-risk and/or advanced hematological malignancies but remains limited by graft-versus-host disease (GVHD). GVHD is initiated by the interaction between recipient antigen presenting cells (APC) and donor T-cells, culminating in T-cell differentiation along pathogenic type-1 (Th1/Tc1) and type-17 (Th17/Tc17) paradigms, at the expense of tolerogenic regulatory T-cell (Treg/Tr1) patterns. Type-1 and type-17 T-cells secrete cytokines (e...

Lineage-defining transcription factors (TFs) are compelling targets for leukemia therapy, yet they are among the most challenging proteins to modulate directly with small molecules. We previously used CRISPR screening to identify a Salt-Inducible Kinase 3 (SIK3) requirement for the growth of acute myeloid leukemia (AML) cell lines that overexpress the lineage TF MEF2C. In this context, SIK3 maintains MEF2C function by directly phosphorylating histone deacetylase 4 (HDAC4), a repressive cofactor of MEF2C. Here, we evaluated whether inhibition of SIK3 with the tool compound YKL-05-099 can suppress MEF2C function and attenuate disease progression in animal models of AML...

In adoptive T-cell immunotherapy of cancer, expansion and persistence of effector cells is a key determinant of response. We tested whether T lymphocytes could be rendered sensitive to erythropoietin (Epo) through ectopic expression of its wild-type receptor, or a truncated form (EpoRm) which augments Epo signaling in erythrocyte progenitors. Both receptors could be expressed in human T lymphocytes; Epo ligation induced STAT5 phosphorylation, which was abrogated by non-toxic concentrations of the JAK1/2 inhibitor ruxolitinib...

No abstract text is available yet for this article.

Genetic predispositions to venous thromboembolism (VTE) are relatively frequent in the general population and comprise a heterogeneous group of disorders. Whereas the most frequent congenital risk factors for thrombosis only moderately increase the risk, a deficiency in antithrombin (AT), one of the most important natural inhibitors of blood coagulation, carries a higher risk. Congenital AT deficiency is an infrequently encountered genetic risk factor for VTE and different subtypes vary with regard to their thrombotic risk...

Antigen escape relapse has emerged as a major challenge for long-term disease control post CD19-directed therapies, to which dual-targeting of CD19 and CD22 has been proposed as a potential solution. Between March 2016 and January 2018, we conducted a pilot study in 89 patients, who had refractory/relapsed B-cell malignancies, to evaluate the efficacy and safety of sequential infusion of anti-CD19 and anti-CD22, two single-specific, third-generation chimeric antigen receptor-engineered (CAR19/22) T-cell "cocktail"...

Primary mediastinal large B-cell lymphomas (PMBL) are aggressive tumors that typically present as large mediastinal masses in young women. PMBLs share clinical, transcriptional and molecular features with classical Hodgkin lymphoma (cHL), including constitutive activation of NF-kB, JAK/STAT signaling and PD-1-mediated immune evasion. The demonstrated efficacy of PD-1 blockade in relapsed/refractory PMBL led to recent approval by the US Food and Drug Administration (FDA) and underscored the importance of characterizing targetable genetic vulnerabilities in this disease...

Sickle cell disease (SCD) leads to significant morbidity and early mortality, and hematopoietic cell transplantation (HCT) is the only widely available cure, with impacts seen on SCD-related organ dysfunction. Outcomes are excellent following matched related donor (MRD) HCT, leading to significantly expanded application of this treatment over the past decade. The majority of SCD patients lack a MRD, but outcomes following alternative donor HCT continue to improve on clinical trials. Within this framework, we aim to provide our perspective on how to apply research findings to clinical practice, for an individual patient...

While acquisition of leukemia-associated somatic mutations by one or more hematopoietic stem cells (HSCs) is inevitable with advancing age, its consequences are highly variable, ranging from clinically silent clonal hematopoiesis (CH) to leukemic progression. To investigate the influence of heritable factors on CH, we performed deep targeted sequencing of blood DNA from 52 monozygotic (MZ) and 27 dizygotic (DZ) twin pairs (aged 70-99 years). Using this highly sensitive approach, we identified CH (Variant Allele Fraction (VAF) {greater than or equal to}0...

The development of Brentuximab vedotin has opened a new era in the management of PTCL. The improved outcomes with BV-CHP versus CHOP in the ECHELON-2 trial are practice changing for common nodal CD30+ PTCLs. Questions regarding the optimal cut off of CD30 expression for BV-CHP therapy and the efficacy and safety of BV-CHP in less common subtypes of CD30+ PTCL subtypes await clarification.

To study the mechanisms of relapse in acute lymphoblastic leukemia (ALL), we performed whole-genome sequencing of 103 diagnosis-relapse-germline trios and ultra-deep sequencing of 208 serial samples in 16 patients. Relapse-specific somatic alterations were enriched in 12 genes (NR3C1, NR3C2, TP53, NT5C2, FPGS, CREBBP, MSH2, MSH6, PMS2, WHSC1, PRPS1, and PRPS2) involved in drug response. Their prevalence was 17% in very early relapse (<9 months from diagnosis), 65% in early relapse (9-36 months), and 32% in late relapse (>36 months) groups...

The Platelets for Neonatal Thrombocytopenia (PlaNeT-2) trial reported an unexpected overall benefit of a prophylactic platelet transfusion threshold of 25x109/L compared to 50x109/L for major bleeding and/or mortality in preterm neonates (7% absolute risk reduction). However, some neonates in the trial may have experienced little benefit or even harm from the 25x109/L threshold. We aimed to assess this heterogeneity of treatment effect in the PlaNet-2 trial, in order to investigate whether all preterm neonates benefit from the low threshold...

Clonal hematopoiesis (CH) of indeterminate potential (CHIP) is defined by mutations in myeloid cancer-associated genes with a variant allele frequency of at least 2%. Recent studies have suggested a possible genetic predisposition to CH. To further explore this phenomenon, we conducted a population-based study of 594 twins from 299 pairs aged 73-94 years, all with more than 20 years follow-up. We sequenced DNA from peripheral blood with a customized 21 genes panel at a median coverage of 6179X. The casewise concordance rates for mutations were calculated to assess genetic predisposition...

About one fourth of patients with essential thrombocythemia or primary myelofibrosis carry a somatic mutation of CALR, the gene encoding for calreticulin. A 52-bp deletion (Type I mutation) and a 5-bp insertion (Type II mutation) are the most frequent genetic lesions. The mechanism(s) by which a CALR mutation leads to a myeloproliferative phenotype has been clarified only in part. We studied the interaction between calreticulin and Store Operated Calcium (Ca2+) Entry (SOCE) machinery in megakaryocytes from healthy individuals and from patients with CALR-mutated myeloproliferative neoplasms...

Coagulation factor XIII (FXIII) is the main stabilizer of the fibrin clot. It circulates in plasma as a tetramer of two A and two B subunits. Under physiological conditions, FXIII-A exists as a dimer (FXIII-A2). The interactions between the FXIII-A subunits that stabilize the FXIII-A2 dimer are not fully understood. Therefore, we designed a systematic approach to identify amino acid residues crucial for the expression and stability of FXIII-A2. Based on the available FXIII-A2 crystal structure, we identified 12 amino acid residues forming intersubunit salt bridges and 21 amino acid residues forming hydrogen bonds between the two A-subunits...

Chimeric antigen receptor (CAR) T cells have demonstrated clinical benefit in patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). We undertook a multi-center clinical trial to determine toxicity, feasibility, and response for this therapy. A total of 25 pediatric/young adult patients (age 1-22.5 years) with R/R B-ALL were treated with 19-28z CAR T cells. Conditioning chemotherapy included high dose (3 g/m2) cyclophosphamide (HD-Cy) for seventeen (n=17) patients and low dose ({less than or equal to}1...

FLT3-ITDs (FLT3-internal tandem duplications) are prognostic driver mutations found in acute myeloid leukemia (AML). Although these short duplications occur in 25% of AML patients, little is known about the molecular mechanism underlying their formation. Understanding the origin of FLT3-ITDs would advance our understanding of the genesis of AML. We analysed the sequence and molecular anatomy of 300 FLT3-ITDs to address this issue, including 114 ITDs with additional nucleotides of unknown origin located between the two copies of the repeat...

Nucleophosmin (NPM1) is the most commonly mutated gene in acute myeloid leukemia (AML). AML with mutated NPM1 is recognised as a separate entity in the World Health Organisation 2016 classification, and carries a relatively favourable prognosis. NPM1 mutations are predominantly 4 bp duplications or insertions in the terminal exon that arise through an unknown mechanism. Here we analyse 2430 NPM1 mutations from 2329 adult and 101 pediatric patients to address their origin. We show that NPM1 mutations display the hallmarks of replication slippage, but lack suitable germline microhomology available for priming...

No abstract text is available yet for this article.