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The familial occurrence of hematological malignancies has been underappreciated. Recent studies suggest that up to 15% of adults with myeloid neoplasms carry germline pathogenic variants in cancer-predisposing genes. This study aimed to identify the underlying germline predisposition variant in patients with a strong family or personal onco-hematological history using whole exome sequencing on sixteen uncharacterized individuals. It was carried out in two groups of patients, one with samples available from two affected relatives (Cohort A) and one with available samples from the index case (Cohort B). In Cohort A, six families were characterized. Two families shared variants in genes associated with DNA damage response and involved in cancer development (CHEK2 and RAD54L). Pathogenic or likely pathogenic germline variants were also found in novel candidate genes (NFATC2 and TC2N). In two families, any relevant pathogenic or likely pathogenic genomic variants were identified. In Cohort B, four additional index cases were analyzed. Three of them harbor clinically relevant variants in genes with a probable role in the development of inherited forms of hematological malignancies (GATA1, MSH4 and PRF1). Overall, whole exome sequencing is a useful approach to achieve a further characterization of these patients and their mutational spectra. Moreover, further investigations may help improve optimization for disease management of affected patients and their families.

FLT3-internal tandem duplication (ITD) analysis is not typically performed in cDNA samples and is not considered an appropriate marker for monitoring measurable residual disease (MRD). The aims of this study were to compare FLT3-ITD mutation analysis in DNA and cDNA samples at diagnosis and to demonstrate the usefulness of its expression measurement as an MRD marker after allogeneic stem cell transplantation (allo-HSCT) or FLT3 inhibitor (FLT3i) administration. A total of 46 DNA and cDNA diagnosis samples, 102 DNA and cDNA post-allo-HSCT samples from 34 patients and 37 cDNA samples from 7 patients with refractory/relapse AML treated with FLT3i were assessed for the FLT3-ITD mutation through fragment analysis. In terms of sensitivity, the analysis of cDNA was superior to that of DNA, quantifying higher allelic ratio values in most cases at diagnosis, and thus optimizing the detection of minor clones and prognostic classification. Regarding the last sample before post-HSCT relapse, cDNA analysis anticipated relapse in most cases, unlike DNA analyses. With regard to the post-FLT3i follow-up, FLT3-ITD expression was reduced after the first FLT3i cycle when the treatment was effective, whereas it was not reduced in refractory patients. FLT3-ITD expression could be a useful additional biomarker at diagnosis and for the assessment of MRD after allo-HSCT and FLT3i in AML.

Although acute myeloid leukemia (AML) with NPM1 mut /FLT3-ITDneg is a low-risk entity, its relapse rate remains high. Out of 333 AML patients, 27 were NPM1 mut, and were analyzed in greater detail in order to find associations between clinical and molecular features and cumulative incidence of relapse. Next-generation sequencing (NGS) was performed on diagnosis and remission samples using two capture-based panels. The presence of the FLT3 D835 variant at diagnosis and a qPCR value of NPM1 mut ≥0.1% after induction chemotherapy were associated with an increased probability of relapse, especially if both conditions are present together. By contrast, patients in which the main clone found at diagnosis harbored NPM1 variant had a lower risk of relapse. Nineteen of the 85 variants found at diagnosis were detected by NGS in remission. AML Subgroup with NPM1 mut/FLT3-ITDneg is a heterogeneous entity, which can be further risk-stratified based on molecular biomarkers.

Conventional cytogenetics are the gold standard for the identification of chromosomal alterations recurrent in myeloid neoplasms. Some next-generation sequencing (NGS) panels are designed for the detection of copy number variations (CNV) or translocations, however, their use is far from being widespread. Here we report on the results of a commercial panel including frequent mutations, CNVs and translocations in myeloid neoplasms. Frequent chromosomal alterations were analyzed by NGS in 135 patients with myeloid neoplasms and three with acute lymphoblastic leukemia. NGS analysis was performed using the enrichment-capture Myeloid Neoplasm-GeneSGKit (Sistemas Genómicos, Spain) gene panel including 35 genes for mutational analysis and frequent CNVs and translocations. NGS results were validated with cytogenetics and/or MLPA when possible. A total of 66 frequent alterations included in NGS panel were detected, 48 of them detected by NGS and cytogenetics. Ten of them were observed only by cytogenetics (mainly trisomy 8), and another eight only by NGS (mainly deletion of 12p). Aside from this, 38 secondary CNVs were detected in any of the genes included mainly for mutational analysis. NGS represents a reliable complementary source of information for the analysis of CNVs and translocations. Moreover, NGS could be a useful tool for the detection of alterations not observed by conventional cytogenetics.

Introduction: Chimeric antigen receptor (CAR) T-Cell therapy is approved for relapse/refractory diffuse large B cell lymphoma (DLBCL) patients after two lines of therapy. Although it is an effective treatment, approximately 20-30% of patients have an early relapse. In this context, biomarkers that helps to identify those patients who will be refractory to this therapy are relevant. Cell-free DNA (cfDNA) has emerged as a new tool for non-invasive monitoring of patients with lymphoma, therefore the aim of this study was to evaluate dynamic cfDNA concentration in addition to other biomarkers (LDH, CRP, ferritin) before CAR T-cell infusion to detect early progressors. Methods: We selected 44 r/r DLBCL patients treated with CAR T-cell in our centre. Plasma samples were collected pre-apheresis (PA) and pre-infusion (PI)(∆cfDNA). Other biomarkers (LDH, CRP, Ferritin) were studied PA, pre-lymphodepletion (PL) and PI, tumour volume metabolic (TMV) are also studied. CfDNA were obtained from plasma using QIAamp® Circulating Nucleic Acid (Qiagen) and quantified by QuantiFluor dsDNA System (Promega). The Mann-Whitney test was used to compare differences between two independent quantitative variables . ROC analysis was conducted to determine the cut-off value of biomarkers. Cumulative incidence of progression (1 and 3 months) was calculated from the date of CAR T-cell infusion. Data analysis was performed using Stata. Results: Cumulative incidence of relapse at 1 month and 3 months was 20% and 30% respectively. The correlation between the progression (1 month, 3 months) and the different biomarkers is shown in Table 1. The CRP PL, CRP PI, LDH PI and ∆cfDNA (PI-PA, median time 41.5 days [range:31-107]) was correlated with early progression (1 month). No differences were found with progression at 3 months. The different cut-off for the biomarkers selected was 9 ng/mL for ∆cfDNA, 225 U/L for LDH and 1.35 mg/dL for CRP. Cumulative incidence of progression at 1 month was calculated for these biomarkers (figure 1): ∆cfDNA, HR: 4.3 (1.05-17), p=0.042; CRP PL: HR: 6.9 (1.5-31.1), p=0.012; CRP PI, HR: 11.2 (1.5-83), p=0.019 and LDH PI, HR: 3.4 (1-17) p=0.11. It should be noted that 83.3% (10/12) of the patients who progressed during the first month had at least one of the above variables. Conclusions: Our results highlight that increase in cfDNA higher than 9 ng/mL, CRP PL and PI >1.35 mg/dL and LDH PI > 225 U/L before CAR T-cell therapy may detect early progressors within the first month after treatment. Therefore, ∆cfDNA, CRP and LDH could be useful to identify patients who highly probable will not benefit from the CAR T infusion, in which another prior strategy could be considered in an attempt to control the disease. These results need to be confirmed with a larger cohort. Figure 1 Figure 1. Disclosures Bailén: Pfizer: Honoraria; Kite-Gilead: Honoraria; Gilead: Honoraria. Kwon: Gilead: Honoraria.

INTRODUCTION Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been established as a powerful treatment modality for patients with hematological malignancies. The graft-versus-leukemia effect, however, is strongly associated with the occurrence of graft-versus-host disease (GVHD) and subsequent transplant-related mortality (TRM). Several strategies are applied in order to prevent GVHD, the post-transplant cyclophosphamide (PT-Cy) is one of the most used in Haploidentical HSCT (Haplo-HSCT). Cyclophosphamide (CY) is an alkylating agent with antineoplastic and immunosuppressive activities. CY is metabolized by highly polymorphic enzymes to produce phosphoramide mustard which is a bifunctional DNA alkylating agent, is the therapeutically active metabolite. Thus, the aim of our study is to identity polymorphisms in the genes of the CY metabolism and correlated with complications post-HSCT (GVHD, TRM, veno-occlusive disease (VOD) or hemorrhagic cystitis (HC)). METHODS We selected 182 consecutive patients who received an Haplo-HSCT from 2007 to 2019. Eleven genes related to CY metabolism were analyzed (Table 1). The genotyping was performed in peripheral blood samples for recipient using an enrichment-capture custom gene panels (IDT probes) in a MiSeq platform (Illumina, USA). The bioinformatic analysis was carried out with BaseSpace software (Illumina, USA). Variants located in coding region and splicing sites were analyzed. We selected polymorphisms corresponding to read depth ≥30X in the canonical isoform with an allele frequency ≥0.4 and represented in at least 5% in our cohort. The collected clinical variables were age/gender recipient and donor, pathology, pretransplant status, conditioning regimen, total body irradiation, basal ferritin and CMV reactivation. Fisher test was used to compare the differences among groups. Statistical Package for the Social Sciences (SPSS, Chicago, USA) was used for statistical test. RESULTS The cumulative incidence rates for aGVHD of II-IV and III-IV grades at 100 days was 39% and 12% respectively. The cumulative incidence rates for cGVHD, moderate or severe cGVHD and TRM at 1000 days were 37%, 19% and 29%, respectively. Among the cases analyzed, 9% developed VOD and 25% HC. Patients who received ablative conditioning regimen presented a higher incidence of TRM (p=0.005). No other clinical data was associated with complications post HSCT. Forty polymorphisms were detected in 9 genes by bioinformatic analysis. The variants that presents some correlation (p Overall, polymorphisms related with decrease activity of enzymes that active cyclophosphamide (level lor active metabolite) were correlated with higher aGVHD, cGVHD, TRM and VOD (Table 1). On the other hand, polymorphisms associated with low activity in detoxification enzymes were correlated with higher toxicity (TRM). As described in bibliography, GSTM1 null allele were correlated with higher probability of developing VOD. CONCLUSIONS Genetic analysis of CY metabolism genes correlated with several post HSCT complications. The analyses of this variants before transplant could facilitate personalized risk and clinical management of patients undergoing Haplo HSCT. Results must validated in others cohorts of patients. Disclosures Kwon: Gilead: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Jazz: Consultancy, Honoraria.

Molecular diagnosis of myeloid neoplasms (MN) is based on the detection of multiple genetic alterations using various techniques. Next-generation sequencing (NGS) has been proved as a useful method for analyzing many genes simultaneously. In this context, we analyzed diagnostic samples from 121 patients affected by MN and ten relapse samples from a subset of acute myeloid leukemia patients using two enrichment-capture NGS gene panels. Pathogenicity classification of variants was enhanced by the development and application of a custom onco-hematology score. A total of 278 pathogenic variants were detected in 84% of patients. For structural alterations, 82% of those identified by cytogenetics were detected by NGS, 25 of 31 copy number variants and three out of three translocations. The detection of variants using NGS changed the diagnosis of seven patients and the prognosis of 15 patients and enabled us to identify 44 suitable candidates for clinical trials. Regarding AML, six of the ten relapsed patients lost or gained variants, comparing with diagnostic samples. In conclusion, the use of NGS panels in MN improves genetic characterization of the disease compared with conventional methods, thus demonstrating its potential clinical utility in routine clinical testing. This approach leads to better-adjusted treatments for each patient.

Chimerism refers to the relative proportion of donor and recipient DNA after hematopoietic stem cell transplantation (HSCT) and its quantitative follow-up is of great clinical utility in this setting. PCR of short tandem repeats (STR-PCR) constitutes the gold standard method for chimerism quantification, although more sensitive PCR techniques (such as qPCR) have recently arisen. We compared the sensitivity and the quantification capacity of both techniques in patient samples and artificial mixtures and demonstrated adequate performance of both methods, with higher sensitivity of qPCR and better quantification skills of STR-PCR. By qPCR, we then prospectively followed up 57 patients that were in complete chimerism (CC) by STR-PCR. Twenty-seven patients (59%) showed 0.1&ndash, 1% recipient DNA in the bone marrow. Only 4 patients presented 0.1&ndash, 1% recipient DNA in peripheral blood (PB), and one of them relapsed. Finally, by qPCR, we retrospectively studied the last sample that showed CC by STR-PCR prior to relapse in 8 relapsed patients. At a median of 59 days prior to relapse, six patients presented mixed chimerism by qPCR in PB. Since both approaches have complementary characteristics, we conclude that different techniques should be applied in different clinical settings and therefore propose a methodological algorithm for chimerism follow-up after HSCT.

INTRODUCTION Allogeneic haematopoietic stem cell transplant (allo-HSCT) could be the only curative therapy for patients with hematological malignancies due to graft effect against tumor. However, approximately 40% of patients develop post-transplantation complications such as acute graft-versus-host disease (aGVHD). Cytokines and their receptors are involved in regulatory and inflammatory processes that occur during GVHD. Therefore, the analysis of polymorphisms (SNPs) that affect the expression or activity of these genes could be used as biomarkers to predict the development of these complication. The aim of this study was to select new polymorphisms in cytokine genes (interleukins, chemokines and their receptors) to build models to predict the development of aGVHD after allo-HSCT from an HLA-identical sibling donor. METHODS We retrospectively selected 88 patients with hematological malignancies who received an allo-HSCT from an HLA-identical sibling donor from 2000 to 2015. A total of 176 pre-transplant recipient (R) and donor (D) peripheral blood samples were collected. The genotyping was performed using an enrichment-capture gene panels (include 132 genes (73 interleukins, 59 chemokines) in a HiSeq platform (Illumina, USA). The bioinformatic analysis was carried out with the GeneSystemssoftware (Sistemas Genómicos, Spain). Variants located in coding region, splicing sites, and UTR, 5'upstream and 3'downstream zones (+ 200pb) were analyzed. We selected polymorphisms corresponding to non-synonymous variants, represented in at least 5% of our cohort, with readings ≥30X in the canonical isoformwith an allele frequency ≥ 0.4. Fisher test was used to compare the differences among groups. Multiple logistic regression models were performed using combination of interleukins and chemokines polymorphisms selected previously that could be applied to clinical practice to predict aGVHD. The models with the highest AUC value, sensitivity and specificity value and the lowest number of genetic variants used were selected.Statistical Package for the Social Sciences (SPSS, Chicago, USA) was used for statistical test. RESULTS The cumulative incidence rates for aGVHD of grades II-IV and III-IV at 100 days after transplantation were 48.93% and 18.08%, respectively. The clinical variables (age, gender, pathology, stem cell source and previous transplantation) were not correlated with II-IV or III-IV aGVHD. However, patients who received ablative conditioning regimen presented a lower incidence of III-IV aGVHD (p= 0.041). Using filters defined previously, we detected 481 polymorphisms (350 coincident, 68 specific R and 63 for D) in the interleukins group. On the other hand, we detected 339 polymorphisms (267 coincident, 29 specific R and 43 for D) in the group of chemokines. Finally, 17 polymorphisms were selected in the interleukin group and 10 in the chemokine group for its correlation with the aGVHD (p We developed multiple logistic regression models for II-IV and III-IV aGVHD in interleukins and chemokines genes (Table 3). The identification of these 15 polymorphisms could help us to prevent the developing II-IV and III-IV aGVHD. CONCLUSIONS We have identified new genetic polymorphisms correlate with the risk of developing aGVHD after allo-HSCT from an HLA-identical sibling donor. Based on these data, we have developed a genetic score that encompasses polymorphisms of greater relevance. In this way, patients at greatest risk for developing this type of post-transplantation complication who could benefit from personalized management through immunosuppression and other drugs. Disclosures No relevant conflicts of interest to declare.

Besides its role in body weight control leptin may also act as a vasoactive hormone. This study was designed to investigate whether leptin modifies angiotensin II (ANG II)-induced vascular responses. The expression of functional leptin receptors (OB-Rb) was detected in vascular smooth muscle cells (VSMCs) from adult Wistar rats by RT-PCR. Immunocytochemistry and Western blot analysis further showed the expression of OB-R protein in VSMCs. The ANG II (10(-7) mol/liter)-induced increase in intracellular Ca(2+) was blocked (P < 0.01) by leptin (10(-8) mol/liter). Moreover, in calcium-free buffer leptin was able to inhibit 65% of the ANG II-induced calcium release from intracellular stores. In endothelium-denuded aortic rings from adult Wistar rats no effect of leptin on basal tension was observed. However, the ANG II-induced isometric contraction was reduced (P < 0.05) by leptin (10(-8) mol/liter). The experiments were also performed in age- and sex-matched Zucker rats, in which no effect of leptin on ANG II-induced calcium increase and vasoconstriction was observed. It is concluded that leptin blocks the vasoconstrictor action of ANG II and inhibits the ANG II-induced increase in intracellular Ca(2+) in VSMCs through OB-Rb. These findings provide new insight into the physiological effects of leptin on blood pressure regulation.

BACKGROUND: Torasemide and furosemide are diuretics that inhibit the Na(+), K(+), 2Cl(-) co-transporter localized in cells from the ascending limb of the loop of Henle. The effects of torasemide and furosemide on cell growth induced by angiotensin II (Ang II) were investigated in cultured vascular smooth muscle cells (VSMCs) obtained from the aorta of adult spontaneously hypertensive rats (SHR). METHODS: Cell growth was determined by DNA and protein synthesis as measured by [3H]thymidine and [3H]leucine incorporation, respectively. Proliferation of VSMCs was measured using a non-radioactive colorimetric cell proliferation assay. RESULTS: Ang II (10(-7) M) signficantly increased DNA and protein synthesis and cell proliferation in VSMCS: These effects were completely abolished by the Ang II type 1 receptor antagonist irbesartan (10(-6) M). Ang II-induced [3H]leucine incorporation was reduced in a dose-dependent way by torasemide (IC(50) value: 7.7+/-0.8x10(-7) M) but not by furosemide. Neither torasemide nor furosemide modified Ang II-stimulated [3H]thymidine incorporation or proliferation in VSMCs. CONCLUSIONS: These results indicate that torasemide, but not furosemide, inhibits Ang II-induced protein synthesis in VSMCs from SHR. Thus, it is suggested that the capacity of torasemide to block this trophic action of Ang II in rat VSMCs is not mediated by inhibition of the Na(+), K(+), 2Cl(-) co-transport mechanism.

Abstract —Torasemide is a loop diuretic that is effective at low once-daily doses in the treatment of arterial hypertension. Because its antihypertensive mechanism of action may not be based entirely on the elimination of salt and water from the body, a vasodilator effect of this drug can be considered. In the present study, the ability of different concentrations of torasemide to modify angiotensin II (Ang II)–induced vascular responses was examined, with the use of an organ bath system, in endothelium-denuded aortic rings from spontaneously hypertensive rats. Ang II–induced increases of intracellular free calcium concentration ([Ca 2+ ] i ) were also examined by image analysis in cultured vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats. A dose-response curve to Ang II was plotted for cumulative concentrations (from 10 −9 to 10 −6 mol/L) in endothelium-denuded aortic rings (pD 2 =7.5±0.3). Isometric contraction induced by a submaximal concentration of Ang II (10 −7 mol/L) was reduced in a dose-dependent way by torasemide (IC 50 =0.5±0.04 μmol/L). Incubation of VSMCs with different concentrations of Ang II (from 10 −10 to 10 −6 mol/L) resulted in a dose-dependent rise of [Ca 2+ ] i (pD 2 =7.5±0.3). The stimulatory effect of [Ca 2+ ] i induced by a submaximal concentration of Ang II (10 −7 mol/L) was blocked by torasemide (IC 50 =0.5±0.3 nmol/L). Our findings suggest that torasemide blocks the vasoconstrictor action of Ang II in vitro. This action can be related to the ability of torasemide to block the increase of [Ca 2+ ] i induced by Ang II in VSMCs. It is proposed that these actions might be involved in the antihypertensive effect of torasemide observed in vivo.

Background. The direct effects of torasemide and furosemide on vasoconstriction and increases in intracellular free calcium concentration ([Ca 2+ ] i ) induced by endothelin-1 (ET-1) were investigated in the aorta of spontaneously hypertensive rats (SHR). Methods. Vascular responses were assessed in endothelium-denuded aortic rings using an organ bath system. Changes of [Ca 2+ ] i in cultured vascular smooth muscle cells (VSMCs) were assessed using fura-2 methodology. Results. ET-1-induced vasoconstriction was reduced in a dose-dependent way by torasemide and furosemide (IC 50 values: 4.3 ± 1.4 × 10 -5 and 9.8 ± 5.6 × 10 -5 M, respectively). The ET-1-induced biphasic [Ca 2+ ] i increase was blocked by torasemide (IC 50 = 2.0 ± 0.2 × 10 8 and 2.7 ± 0.6 × 10 6 M, respectively). Furosemide inhibited the initial rise in [Ca 2+ ] i induced by ET-1, with no effect on the second rise. The specific chloride (Cl - ) channel blocker diphenylamine-2-carboxylate inhibits both ET-1-induced responses in VSMCs (IC 50 = 8.0 ± 0.3 × 10 -9 and 2.5 ± 0.7 × 10 -7 M. respectively). Conclusions. These results suggest that the ability of loop diuretics to interfere with the vascular actions of ET-1 may involve different molecular mechanisms. The ability of torasemide to block the vasoconstrictive action of ET-1 could include an inhibitory action on Cl channels.