Evaluation of the primitive fraction by functional in vitro assays at the RNA and DNA level represents a novel tool for complementing molecular monitoring in chronic myeloid leukemia

Quantification of BCR-ABL1 mRNA levels in peripheral blood of chronic myeloidleukemia patients is a strong indicator of response to tyrosine-kinase inhibitors (TKI)treatment. However, additional prognostic markers are needed in order to better classify patients. The hypothesis of leukemic stem cells (LSCs) heterogeneity and persistence, suggests that their functional evaluation could be of clinical interest. In this work, we assessed the primitive and progenitor fractions in patients at diagnosis and during TKI treatment using functional in vitro assays, defining a ?functional leukemic burden? (FLB). We observed that the FLB was reduced in vivo in both fractions upon treatment. However, different FLB levels were observed among patients according to their response to treatment, suggesting that quantification of the FLB could complement early molecular monitoring. Given that FLB assessment is limited by BCR-ABL1 mRNA expression levels, we developed a novel detection method of primitive cells at the DNA level, using patient-specific primers and direct nested PCR in colonies obtained from functional in vitro assays. We believe that this methodcould be useful in the context of discontinuation trials, given that it is unknown whether the persistent leukemic clone represents LSCs, able to resume the leukemia upon TKI removal.Fil: Ruiz, María Sol. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Sanchez, María Belén. Fundación Cáncer. Centro de Investigaciones Oncológicas; Argentina. Argenomics; ArgentinaFil: Gutierrez, Leandro German. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Instituto Alexander Fleming, Bs. As.; ArgentinaFil: Koile, Daniel Isaac. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Yankilevich, Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Mosqueira, Celeste. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Cranco, Santiago. Fundaleu; ArgentinaFil: Custidiano, María del Rosario. Hospital Italiano de La Plata; ArgentinaFil: Freitas, Josefina. Provincia de Buenos Aires. Hospital Nacional Profesor A. Posadas; ArgentinaFil: Foncuberta, Cecilia. Instituto Alexander Fleming; ArgentinaFil: Moiraghi, Beatriz. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Pavlovsky, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Pérez, Mariel Ana. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Ventriglia, Verónica. Provincia de Buenos Aires. Hospital Nacional Profesor A. Posadas; Argentina; ArgentinaFil: Sánchez Ávalos, Julio César Américo. Instituto Alexander Fleming; ArgentinaFil: Mordoh, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Larripa, Irene Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Bianchini, Michele. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Cáncer. Centro de Investigaciones Oncológicas; Argentin

The Latin American experience of allografting patients with severe aplastic anaemia: real-world data on the impact of stem cell source and ATG administration in HLA-identical sibling transplants

We studied 298 patients with severe aplastic anaemia (SAA) allografted in four Latin American countries. The source of cells was bone marrow (BM) in 94 patients and PBSCs in 204 patients. Engraftment failed in 8.1% of recipients with no difference between BM and PBSCs (P = 0.08). Incidence of acute GvHD (aGvHD) for BM and PBSCs was 30% vs 32% (P = 0.18), and for grades III–IV was 2.6% vs 11.6% (P = 0.01). Chronic GvHD (cGvHD) between BM and PBSCs was 37% vs 59% (P = 0.002) and extensive 5% vs 23.6% (P = 0.01). OS was 74% vs 76% for BM vs PBSCs (P = 0.95). Event-free survival was superior in patients conditioned with anti-thymocyte globulin (ATG)-based regimens compared with other regimens (79% vs 61%, P = 0.001) as excessive secondary graft failure was seen with other regimens (10% vs 26%, P = 0.005) respectively. In multivariate analysis, aGvHD II–IV (hazard ratio (HR) 2.50, confidence interval (CI) 1.1–5.6, P = 0.02) and aGvHD III–IV (HR 8.3 CI 3.4–20.2, Po0.001) proved to be independent negative predictors of survival. In conclusion, BM as a source of cells and ATG-based regimens should be standard because of higher GvHD incidence with PBSCs, although the latter combining with ATG in the conditioning regimen could be an option in selected high-risk patient

In-depth characterization of NK cell markers from CML patients who discontinued tyrosine kinase inhibitor therapy

IntroductionTreatment-free remission (TFR) in patients with chronic myeloid leukemia in chronic phase is considered a safe option if suitable molecular monitoring is available. However, the question arises as to which factors can contribute to the maintenance of TFR, and immunologic surveillance of the remaining leukemic cells is believed to be one of them. Argentina Stop Trial is an open-label, single-arm, multicenter trial assessing TFR after tyrosine kinase inhibitors interruption, that after more than 4 years showed a successful TFR rate of 63%.MethodsIn this context, we set up an immunological study by flow cytometry in order to analyze specific NK cell subsets from peripheral blood patient samples both at the time of discontinuation as well as during the subsequent months.ResultsAt the time of discontinuation, patients show a mature NK cell phenotype, probably associated to TKI treatment. However, 3 months after discontinuation, significant changes in several NK cell receptors occurred. Patients with a higher proportion of CD56dim NK and PD-1+ NK cells showed better chances of survival. More interestingly, non-relapsing patients also presented a subpopulation of NK cells with features associated with the expansion after cytomegalovirus infection (expression of CD57+NKG2C+), and higher proportion of NKp30 and NKp46 natural cytotoxicity receptors, which resulted in greater degranulation and associated with better survival (p<0.0001).DiscussionThis NK cell subset could have a protective role in patients who do not relapse, thus further characterization could be useful for patients in sustained deep molecular response

Interplay between DMD point mutations and splicing signals in Dystrophinopathy phenotypes.

DMD nonsense and frameshift mutations lead to severe Duchenne muscular dystrophy while in-frame mutations lead to milder Becker muscular dystrophy. Exceptions are found in 10% of cases and the production of alternatively spliced transcripts is considered a key modifier of disease severity. Several exonic mutations have been shown to induce exon-skipping, while splice site mutations result in exon-skipping or activation of cryptic splice sites. However, factors determining the splicing pathway are still unclear. Point mutations provide valuable information regarding the regulation of pre-mRNA splicing and elements defining exon identity in the DMD gene. Here we provide a comprehensive analysis of 98 point mutations related to clinical phenotype and their effect on muscle mRNA and dystrophin expression. Aberrant splicing was found in 27 mutations due to alteration of splice sites or splicing regulatory elements. Bioinformatics analysis was performed to test the ability of the available algorithms to predict consequences on mRNA and to investigate the major factors that determine the splicing pathway in mutations affecting splicing signals. Our findings suggest that the splicing pathway is highly dependent on the interplay between splice site strength and density of regulatory elements

Transforming growth factor-β1 functional polymorphisms in myeloablative sibling hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) with sibling donors (s.d.) is a life-saving intervention for patients with hematologicalmalignancies. Numerous genetic factors have a role in transplant outcome. Several functional polymorphisms have been identifiedin TGF-β1 gene, such as single-nucleotide polymorphism (SNP) at +29C4T within exon 1. Two hundred and forty five patient/donorpairs who underwent a s.d. HSCT in our centers were genotyped for this SNP. In the myeloablative cohort, +29CC donors wereassociated with an increase in severe chronic GvHD (32% vs 16%, hazard ratio (HR) 9.0, P = 0.02). Regarding survival outcomes,+29CC patients developed higher non relapse mortality (NRM) (1?5 years CC 28?32% vs TC/TT 7?10%; HR 5.1, P = 0.01). Recipientsof +29TT donors experienced a higher relapse rate (1?5 years TT 37?51% vs TC 19?25% vs CC 13%?19%; HR 2.4, P = 0.01) witha decreased overall survival (OS) (1?5 years TT 69?50% vs TC/CC 77?69%; HR 1.9, P = 0.05). Similar to previous myeloablativeunrelated donors HSCT results, we confirmed that +29CC patients had higher NRM. In addition we found that +29TT donors mightbe associated with a higher relapse rate and lower OS. These results should be confirmed in larger series. Identification of theseSNPs will allow personalizing transplant conditioning and immunosuppressant regimens, as well as assisting in the choice of themost appropriate donor.Fil: Berro, Mariano. Universidad Austral; ArgentinaFil: Palau Nagore, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Rivas, M. M.. Universidad Austral; ArgentinaFil: Longo, P.. Universidad Austral; ArgentinaFil: Foncuberta, Cecilia. Instituto Alexander Fleming; ArgentinaFil: Vitriu, Adriana. Instituto Alexander Fleming; ArgentinaFil: Remaggi, Guillermina. Fundaleu; ArgentinaFil: Martinez Rolón, Juliana. Fundaleu; ArgentinaFil: Jaimovich, Gregorio. Fundación Favaloro; ArgentinaFil: Requejo, Alejandro. Fundación Favaloro; ArgentinaFil: Feldman, Leonardo. Fundación Favaloro; ArgentinaFil: Padros, Karín. Fundación Favaloro; ArgentinaFil: Rodriguez, María Beatriz. Fundación Favaloro; ArgentinaFil: Shaw, B. E.. Medical College Of Wisconsin; Estados UnidosFil: Larripa, Irene Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Belli, Carolina Bárbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Kusminsky, Gustavo. Universidad Austral; Argentin

Exonic mutations associated with exon-skipping events.

<p>On the left, semi-quantification of alternative transcripts by QF-PCR on muscle biopsy cDNA. In the centre, schematic representation of the detected transcript species and their relative ratio. On the right, mutation sequence context and predicted ESE motifs: blue bars indicate ESE finder SR protein binding sites; violet bars indicate Rescue-ESE hexamers; red bars indicate PESE octamers. The mutated nucleotide is indicated in red.</p

Elevated plasma levels of IL-6 and MCP-1 selectively identify CML patients who better sustain molecular remission after TKI withdrawal

Abstract Treatment-free remission (TFR) in chronic myeloid leukemia (CML) is safe under adequate molecular monitoring, but questions remain regarding which factors may be considered predictive for TFR. Argentina Stop Trial (AST) is a multicenter TFR trial showing that 65% of patients sustain molecular remission, and the prior time in deep molecular response (DMR) was associated with successful TFR. Luminex technology was used to characterize cytokines in plasma samples. Using machine learning algorithms, MCP-1 and IL-6 were identified as novel biomarkers and MCP-1low/IL-6low patients showed eightfold higher risk of relapse. These findings support the feasibility of TFR for patients in DMR and MCP-1/IL-6 plasma levels are strong predictive biomarkers