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1.
Haematologica ; 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31537695

RESUMO

Although studies of mixed chimerism following hematopoietic stem cell transplantation in patients with sickle cell disease may provide insights into the engraftment needed to correct the disease and into immunological reconstitution, an extensive multilineage analysis is lacking. We analyzed chimerism simultaneously in peripheral erythroid and granulomonocytic precursors/progenitors, highly purified B and T-lymphocytes, monocytes, granulocytes and red blood cells. Thirty-four patients with mixed chimerism and ≥12 months of follow-up were included. A selective advantage of donor red blood cells and their progenitors/precursors led to full chimerism in mature red blood cells (despite partial engraftment of other lineages), and resulted in the clinical control of the disease. Six patients with donor chimerism <50% had hemolysis (reticulocytosis) and higher HbS than their donor. Four of them had donor chimerism <30%, including a patient with AA donor (hemoglobin >10g/dL) and 3 with AS donors (hemoglobin <10g/dL). However, only one vaso-occlusive crisis occurred with 68.7% HbS. Except in the patients with lowest chimerism, the donor engraftment was lower for T cells than for the other lineages. In a context of mixed chimerism after hematopoietic stem cell transplantation for sickle cell disease, myeloid (rather than T cell) engraftment was the key efficacy criterion. Results show that myeloid chimerism as low as 30% was sufficient to prevent vaso-occlusive crisis in transplants from an AA donor but not constantly from an AS donor. However, the correction of hemolysis requires higher donor chimerism levels (i.e. ≥50%) in both AA and AS recipients. In the future, this group of patients may need a different therapeutic approach.

2.
Haematologica ; 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31097628

RESUMO

Allogeneic stem cell transplantation remains the only curative treatment for sickle-cell anemia, but the place of myeloablative conditioning remains to be defined. The aim of the present study was to analyze long-term outcomes, including chimerism, sickle-cell anemia-related events and biological data (hemoglobin, reticulocytes, HbS%), and fertility, in a French series of 234 SCA-patients younger than 30 years who received (1988-2012) a matched-sibling-donor stem cell transplantation following standardized myeloablative conditioning (Busulfan, Cyclophosphamide and rabbit anti-thymocyte globulin). Since the first report of the series (1988-2004), 151 new consecutive patients with sickle-cell anemia were similarly transplanted. Considering death, non-engraftment or rejection (donor cells<5%) as events, the 5-year event-free survival was 97.9% (95% confidence interval:95.5-100%), confirming at least 95% chance of cure since year 2000. In the overall cohort (n=234, median follow-up of 7.9 years), event-free survival was not associated with age, but chronic-graft-vs-host disease was independently associated with recipien's age>15 (hazard ratio=4.37,P=0.002) and lower (5-15 vs 20 mg/kg) anti-thymocyte globulin dose (hazard ratio=4.55,P=0.001). At one year, 44% of patients had mixed chimerism (5-95% donor cells), but those prepared with anti-thymocyte globulin had no graft rejection. No events related to sickle cell anemia occurred in patients with mixed chimerism, even those with 15-20% donor cells, but hemolytic anemia stigmata were observed with donor cells<50%. Currently, myeloablative transplantation with matched-sibling donor has a higher event-free survival (98%) in patients younger than 30 than that reported for non-myeloablative conditioning (88%). Nevertheless, the risk of chronic graft-vs-host disease in older patients and need for fertility preservation might be indications in patients older than 15 for a non-myeloablative conditioning.

4.
Blood ; 134(1): 9-21, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-30940614

RESUMO

Evans syndrome (ES) is a rare severe autoimmune disorder characterized by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. In most cases, the underlying cause is unknown. We sought to identify genetic defects in pediatric ES (pES), based on a hypothesis of strong genetic determinism. In a national, prospective cohort of 203 patients with early-onset ES (median [range] age at last follow-up: 16.3 years ([1.2-41.0 years]) initiated in 2004, 80 nonselected consecutive individuals underwent genetic testing. The clinical data were analyzed as a function of the genetic findings. Fifty-two patients (65%) received a genetic diagnosis (the M+ group): 49 carried germline mutations and 3 carried somatic variants. Thirty-two (40%) had pathogenic mutations in 1 of 9 genes known to be involved in primary immunodeficiencies (TNFRSF6, CTLA4, STAT3, PIK3CD, CBL, ADAR1, LRBA, RAG1, and KRAS), whereas 20 patients (25%) carried probable pathogenic variants in 16 genes that had not previously been reported in the context of autoimmune disease. Lastly, no genetic abnormalities were found in the remaining 28 patients (35%, the M- group). The M+ group displayed more severe disease than the M- group, with a greater frequency of additional immunopathologic manifestations and a greater median number of lines of treatment. Six patients (all from the M+ group) died during the study. In conclusion, pES was potentially genetically determined in at least 65% of cases. Systematic, wide-ranging genetic screening should be offered in pES; the genetic findings have prognostic significance and may guide the choice of a targeted treatment.

5.
Acta Obstet Gynecol Scand ; 98(5): 630-637, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30919447

RESUMO

INTRODUCTION: The preservation of fertility is an integral part of care of children requiring gonadotoxic treatments for cancer or non-malignant diseases. In France, the cryopreservation of ovarian tissue has been considered and has been offered as a clinical treatment since its inception. The aim of this study is to review 20 years of activity in fertility preservation by ovarian tissue cryopreservation (OTC) for children and the feasibility of oocyte isolation and cryopreservation from the ovarian tissue at a single center. MATERIAL AND METHODS: Retrospective study including patients aged 15 years or younger who underwent OTC, combined for some with oocyte cryopreservation of isolated oocytes, before a highly gonadotoxic treatment for malignant or non-malignant disease was initiated. We describe the evolution of activities in our program for fertility preservation and patient characteristics at the time of OTC and follow up. RESULTS: From April 1998 to December 2018, 418 girls and adolescents younger than 15 years of age underwent OTC, representing 40.5% of all females who have had ovarian tissue cryopreserved at our center. In all, 313 patients had malignant diseases and 105 had benign conditions. Between November 2009 and July 2013, oocytes were isolated and also cryopreserved in 50 cases. The mean age of patients was 6.9 years (range 0.3-15). The most frequent diagnoses in this cohort included neuroblastoma, acute leukemia and hemoglobinopathies; neuroblastoma being the most common diagnosis in very young patients. During follow up, three patients requested the use of their cryopreserved ovarian tissue. All had undergone ovarian tissue transplantation, one for puberty induction and the two others for restoring fertility. So far, no pregnancies have been achieved. Eighty-four patients who had OTC died. CONCLUSIONS: Ovarian tissue cryopreservation is the only available technique for preserving fertility of girls. To our knowledge this is the largest series of girls and adolescents younger than 15 years so far reported on procedures of OTC before highly gonadotoxic treatment in a single center.

6.
JAMA ; 321(3): 266-276, 2019 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-30667500

RESUMO

Importance: In children with sickle cell anemia (SCA), high transcranial Doppler (TCD) velocities are associated with stroke risk, which is reduced by chronic transfusion. Whether matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) can reduce velocities in patients with SCA is unknown. Objective: To determine the association of MSD-HSCT with TCD velocities as a surrogate for the occurrence of ischemic stroke in children with SCA. Design, Setting, and Participants: Nonrandomized controlled intervention study conducted at 9 French centers. Patients with SCA were enrolled between December 2010 and June 2013, with 3-year follow-up ending in January 2017. Children with SCA were eligible if younger than 15 years, required chronic transfusions for persistently elevated TCD velocities, and had at least 1 sibling without SCA from the same 2 parents. Families agreed to HLA antigen typing and transplantation if a matched sibling donor was identified or to standard care in the absence of a matched sibling donor. Exposures: MSD-HSCT (n = 32), compared with standard care (n = 35) (transfusions for ≥1 year with potential switch to hydroxyurea thereafter), using propensity score matching. Main Outcomes and Measures: The primary outcome was the highest time-averaged mean of maximum velocities in 8 cerebral arteries, measured by TCD (TCD velocity) at 1 year. Twenty-five of 29 secondary outcomes were analyzed, including the highest TCD velocity at 3 years and normalization of velocities (<170 cm/s) and ferritin levels at 1 and 3 years. Results: Sixty-seven children with SCA (median age, 7.6 years; 35 girls [52%]) were enrolled (7 with stroke history). In the matched sample, highest TCD velocities at 1 year were significantly lower on average in the transplantation group (129.6 cm/s) vs the standard care group (170.4 cm/s; difference, -40.8 cm/s [95% CI, -62.9 to -18.6]; P < .001). Of the 25 analyzed secondary end points, 4 showed significant differences, including the highest TCD velocity at 3 years (112.4 cm/s in the transplantation group vs 156.7 cm/s in the standard care group; difference, -44.3 [95% CI, -71.9 to -21.1]; P = .001); normalization rate at 1 year (80.0% in the transplantation group vs 48.0% in the standard care group; difference, 32.0% [95% CI, 0.2% to 58.6%]; P = .045); and ferritin levels at 1 year (905 ng/mL in the transplantation group vs 2529 ng/mL in the standard care group; difference, -1624 [95% CI, -2370 to -879]; P < .001) and 3 years (382 ng/mL in the transplantation group vs 2170 ng/mL in the standard care group; difference, -1788 [95% CI, -2570 to -1006]; P < .001). Conclusions and Relevance: Among children with SCA requiring chronic transfusion because of persistently elevated TCD velocities, MSD-HSCT was significantly associated with lower TCD velocities at 1 year compared with standard care. Further research is warranted to assess the effects of MSD-HSCT on clinical outcomes and over longer follow-up. Trial Registration: ClinicalTrials.gov Identifier: NCT01340404.


Assuntos
Anemia Falciforme/terapia , Circulação Cerebrovascular/fisiologia , Transplante de Células-Tronco Hematopoéticas , Irmãos , Ultrassonografia Doppler Transcraniana , Aloenxertos , Anemia Falciforme/diagnóstico por imagem , Anemia Falciforme/fisiopatologia , Velocidade do Fluxo Sanguíneo , Criança , Feminino , Ferritinas/sangue , Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Masculino , Pontuação de Propensão , Qualidade de Vida , Condicionamento Pré-Transplante
7.
Blood ; 132(13): 1399-1412, 2018 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-29898956

RESUMO

Unlike primary myelofibrosis (PMF) in adults, myelofibrosis in children is rare. Congenital (inherited) forms of myelofibrosis (cMF) have been described, but the underlying genetic mechanisms remain elusive. Here we describe 4 families with autosomal recessive inherited macrothrombocytopenia with focal myelofibrosis due to germ line loss-of-function mutations in the megakaryocyte-specific immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor G6b-B (G6b, C6orf25, or MPIG6B). Patients presented with a mild-to-moderate bleeding diathesis, macrothrombocytopenia, anemia, leukocytosis and atypical megakaryocytes associated with a distinctive, focal, perimegakaryocytic pattern of bone marrow fibrosis. In addition to identifying the responsible gene, the description of G6b-B as the mutated protein potentially implicates aberrant G6b-B megakaryocytic signaling and activation in the pathogenesis of myelofibrosis. Targeted insertion of human G6b in mice rescued the knockout phenotype and a copy number effect of human G6b-B expression was observed. Homozygous knockin mice expressed 25% of human G6b-B and exhibited a marginal reduction in platelet count and mild alterations in platelet function; these phenotypes were more severe in heterozygous mice that expressed only 12% of human G6b-B. This study establishes G6b-B as a critical regulator of platelet homeostasis in humans and mice. In addition, the humanized G6b mouse will provide an invaluable tool for further investigating the physiological functions of human G6b-B as well as testing the efficacy of drugs targeting this receptor.

8.
Transfusion ; 58(6): 1527-1535, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29707783

RESUMO

BACKGROUND: Sickle cell disease (SCD) patients undergo multiple red blood cell (RBC) transfusions and are regularly exposed to low-prevalence (LP) antigens specific to individuals of African descent. This study evaluated the prevalence of antibodies against LP antigens in SCD patients and the need to identify these antibodies in everyday practice. STUDY DESIGN AND METHODS: Plasma from 211 SCD patients was tested with RBCs expressing the following LP antigens: RH10 (V), RH20 (VS), RH23 (DW ), RH30 (Goa ), KEL6 (Jsa ), and MNS6 (He). RESULTS: Nine LP antibodies were found in eight patients (3.8%): five anti-RH23, two anti-RH30, and two anti-MNS6. The exposure risk, calculated for each LP antigen, was below 3% per RBC unit, for all antigens tested. Thus, in this cohort of transfused SCD patients, the prevalence of LP antibodies was similar to that of antibodies against antigens of the FY, JK, and MNS blood group systems. These findings also reveal the occurrence of anti-RH23 in SCD patients. No anti-RH20 or anti-KEL6 were found, despite the high frequency of mismatch situations. CONCLUSION: These results highlight the immunogenicity of these LP antigens, and the evanescence of antibodies against LP antigens. They also highlight the importance of appropriate pretransfusion testing for patients frequently transfused, who are likely to be exposed to multiple types of blood group antigens.

9.
Pediatrics ; 141(Suppl 5): S506-S509, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29610181

RESUMO

Neonatal alloimmune thrombocytopenia (NAIT) is a common but significant challenge for neonatologists and a potentially devastating disease that may lead to intracranial bleeding. The underlying mechanism of thrombocytopenia is expected to be mediated by accelerated clearance of antibody-opsonized fetal platelets. We report severe recurrent NAIT related to human platelet antigen (HPA)-15 systems in 2 consecutive siblings. The first child presented with intracranial hemorrhage at birth and subsequently died. The diagnosis of NAIT, although initially suspected, was ruled out after negative investigation of only HPA-1, HPA-3, and HPA-5 systems. The second child experienced a clinically milder presentation but a profound thrombocytopenia. In both siblings, NAIT was unexpectedly associated with amegakaryocytosis, suggesting that alloimmunization could extend at the megakaryocyte level. In addition, both siblings presented with drastic abnormalities in the B-cell compartment, which led to broad investigations for an immune-deficiency syndrome and provided a novel pathophysiologic hypothesis. Both placental examinations revealed major lymphoid infiltration involving the villous placenta, which is consistent with the diagnosis of villitis of unknown etiology. Severe thrombocytopenia in an otherwise healthy newborn should raise high the suspicion of NAIT. The diagnosis of NAIT should not be ruled out until extensive human platelet antigen systems have been investigated to screen for fetal-maternal antigen incompatibility. This is crucial not only for the newborn to allow optimal lifesaving treatments but also for effective management of future pregnancies. Interestingly, antibodies to HPA-15 have previously been reported with severe NAIT-related thrombocytopenia, but we are the first to report associated in vivo amegakaryocytosis.

10.
N Engl J Med ; 378(16): 1479-1493, 2018 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-29669226

RESUMO

BACKGROUND: Donor availability and transplantation-related risks limit the broad use of allogeneic hematopoietic-cell transplantation in patients with transfusion-dependent ß-thalassemia. After previously establishing that lentiviral transfer of a marked ß-globin (ßA-T87Q) gene could substitute for long-term red-cell transfusions in a patient with ß-thalassemia, we wanted to evaluate the safety and efficacy of such gene therapy in patients with transfusion-dependent ß-thalassemia. METHODS: In two phase 1-2 studies, we obtained mobilized autologous CD34+ cells from 22 patients (12 to 35 years of age) with transfusion-dependent ß-thalassemia and transduced the cells ex vivo with LentiGlobin BB305 vector, which encodes adult hemoglobin (HbA) with a T87Q amino acid substitution (HbAT87Q). The cells were then reinfused after the patients had undergone myeloablative busulfan conditioning. We subsequently monitored adverse events, vector integration, and levels of replication-competent lentivirus. Efficacy assessments included levels of total hemoglobin and HbAT87Q, transfusion requirements, and average vector copy number. RESULTS: At a median of 26 months (range, 15 to 42) after infusion of the gene-modified cells, all but 1 of the 13 patients who had a non-ß0/ß0 genotype had stopped receiving red-cell transfusions; the levels of HbAT87Q ranged from 3.4 to 10.0 g per deciliter, and the levels of total hemoglobin ranged from 8.2 to 13.7 g per deciliter. Correction of biologic markers of dyserythropoiesis was achieved in evaluated patients with hemoglobin levels near normal ranges. In 9 patients with a ß0/ß0 genotype or two copies of the IVS1-110 mutation, the median annualized transfusion volume was decreased by 73%, and red-cell transfusions were discontinued in 3 patients. Treatment-related adverse events were typical of those associated with autologous stem-cell transplantation. No clonal dominance related to vector integration was observed. CONCLUSIONS: Gene therapy with autologous CD34+ cells transduced with the BB305 vector reduced or eliminated the need for long-term red-cell transfusions in 22 patients with severe ß-thalassemia without serious adverse events related to the drug product. (Funded by Bluebird Bio and others; HGB-204 and HGB-205 ClinicalTrials.gov numbers, NCT01745120 and NCT02151526 .).


Assuntos
Terapia Genética , Globinas beta/genética , Talassemia beta/terapia , Adolescente , Adulto , Antígenos CD34 , Criança , Transfusão de Eritrócitos/estatística & dados numéricos , Feminino , Técnicas de Transferência de Genes , Vetores Genéticos , Hemoglobinas/análise , Hemoglobinas/genética , Humanos , Lentivirus/genética , Masculino , Mutação , Transplante Autólogo , Adulto Jovem , Talassemia beta/genética
11.
Blood Adv ; 2(6): 626-637, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29555644

RESUMO

Sickle cell anemia (SCA), albeit monogenic, has heterogeneous phenotypic expression, mainly related to the level of hemoglobin F (HbF). No large cohort studies have ever compared biological parameters in patients with major ß-globin haplotypes; ie, Senegal (SEN), Benin (BEN), and Bantu/Central African Republic (CAR). The aim of this study was to evaluate the biological impact of α genes, ß haplotypes, and glucose-6-phosphate dehydrogenase (G6PD) activity at baseline and with hydroxyurea (HU). Homozygous HbS patients from the Créteil pediatric cohort with available α-gene and ß-haplotype data were included (n = 580; 301 females and 279 males) in this retrospective study. Homozygous ß-haplotype patients represented 74% of cases (37.4% CAR/CAR, 24.3% BEN/BEN, and 12.1% SEN/SEN). HU was given to 168 cohort SCA children. Hematological parameters were recorded when HbF was maximal, and changes (ΔHU-T0) were calculated. At baseline, CAR-haplotype and α-gene numbers were independently and negatively correlated with Hb and positively correlated with lactate dehydrogenase. HbF was negatively correlated with CAR-haplotype numbers and positively with BEN- and SEN-haplotype numbers. The BCL11A/rs1427407 "T" allele, which is favorable for HbF expression, was positively correlated with BEN- and negatively correlated with CAR-haplotype numbers. With HU treatment, Δ and HbF values were positively correlated with the BEN-haplotype number. BEN/BEN patients had higher HbF and Hb levels than CAR/CAR and SEN/SEN patients. In conclusion, we show that BEN/BEN patients have the best response on HU and suggest that this could be related to the higher prevalence of the favorable BCL11A/rs1427407/T/allele for HbF expression in these patients.

12.
Haematologica ; 103(7): 1143-1149, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29599204

RESUMO

In this retrospective study, we evaluate long-term complications in nearly all ß-thalassemia-major patients who successfully received allogeneic hematopoietic stem cell transplantation in France. Ninety-nine patients were analyzed with a median age of 5.9 years at transplantation. The median duration of clinical follow up was 12 years. All conditioning regimens were myeloablative, most were based on busulfan combined with cyclophosphamide, and more than 90% of patients underwent a transplant from a matched sibling donor. After transplantation, 11% of patients developed thyroid dysfunction, 5% diabetes, and 2% heart failure. Hypogonadism was present in 56% of females and 14% of males. Female patients who went on to normal puberty after transplant were significantly younger at transplantation than those who experienced delayed puberty (median age 2.5 vs 8.7 years). Fertility was preserved in 9 of 27 females aged 20 years or older and 2 other patients became pregnant following oocyte donation. In addition to patient's age and higher serum ferritin levels at transplantation, time elapsed since transplant was significantly associated with decreased height growth in multivariate analysis. Weight growth increased after transplantation particularly in females, 36% of adults being overweight at last evaluation. A comprehensive long-term monitoring, especially of endocrine late effects, is required after hematopoietic stem cell transplantation for thalassemia.

13.
Adv Exp Med Biol ; 1013: 89-122, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29127678

RESUMO

Allogeneic hematopoietic stem cell transplantation (HSCT) can cure single gene disorders such as thalassemia and sickle cell anemia (SCA). These non-malignant diseases have in common severe hemolytic anemia and high proliferative bone marrow, requiring frequent transfusions. The risk of rejection is high and graft-vs-host disease is not desirable. Important progress has been made in the management of these diseases, including leukocyte depletion of blood products, and chelation therapy, for both diseases, and erythrocytapheresis and hydroxycarbamide for SCA. However, morbidity and quality of life are still of concern. Results have also significantly improved for HSCT, with the reduction of rejection by using anti-thymocyte globulin (ATG), which also decreases the risk of chronic graft-vs-host disease. Current data show a more than 90% chance of cure with myeloablative conditioning in children with hemoglobinopathy and a geno-identical donor. Results are similar whether the cell source is cord blood or bone marrow. Because of the risk of conditioning-related infertility, ovarian and/or testis cryopreservation should be discussed. Non-myeloablative conditioning regimens have also been successfully developed in adults with SCA and organ dysfunction, making cure possible. These encouraging results should incite to perform HLA typing early in families with hemoglobinopathies, and to systematically propose sibling cord blood cryopreservation for those without geno-identical donor.


Assuntos
Anemia Falciforme/terapia , Transplante de Células-Tronco Hematopoéticas/métodos , Talassemia beta/terapia , Adulto , Soro Antilinfocitário/administração & dosagem , Criança , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Teste de Histocompatibilidade , Humanos , Imunossupressores/administração & dosagem , Qualidade de Vida , Condicionamento Pré-Transplante/métodos , Transplante Homólogo , Resultado do Tratamento
14.
Contemp Clin Trials ; 62: 91-104, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28821470

RESUMO

BACKGROUND: Children with sickle cell anemia (SCA) have an 11% risk of stroke by the age of 18. Chronic transfusion applied in patients detected to be at risk by transcranial Doppler allows a significant reduction of stroke risk. However, chronic transfusion exposes to several adverse events, including alloimmunization and iron overload, and is not curative. Hematopoietic stem cell transplantation allows termination of the transfusion program, but its benefit has not been demonstrated. DESIGN: DREPAGREFFE (NCT01340404) is a multicenter, prospective trial enrolling SCA children younger than 15years receiving chronic transfusion due to a history of abnormal transcranial Doppler (velocities ≥200cm/s). Only those with at least one non-SCA sibling and parents accepting HLA-typing and transplantation with a genoidentical donor were eligible. Chronic transfusion was pursued in patients with no available donor, whereas others were transplanted. Comparison between the 2 arms (transfusion vs transplantation) was analyzed using both genetic randomization and propensity-score matching as a sensitivity analysis. The primary end-point was the velocity measure at 1year. Secondary endpoints were the incidence of stroke, silent cerebral infarcts and stenoses, cognitive performance in comparison with siblings, allo-immunization, iron-overload, phosphatidyl-serine, angiogenesis/hypoxia, brain injury-related factor expression, quality of life and cost. OBJECTIVES: To show that genoidentical transplantation decreases velocities significantly more than chronic transfusion in SCA children at risk of stroke. DISCUSSION: DREPAGREFFE is the first prospective study to evaluate transplantation in SCA children. It compares the outcome of cerebral vasculopathy following genoidentical transplantation versus chronic transfusion using genetic randomization and causal inference methods.


Assuntos
Anemia Falciforme/complicações , Anemia Falciforme/terapia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/métodos , Acidente Vascular Cerebral/etiologia , Reação Transfusional , Adolescente , Transfusão de Sangue/economia , Transfusão de Sangue/métodos , Criança , Pré-Escolar , Cognição , Feminino , Transplante de Células-Tronco Hematopoéticas/economia , Humanos , Sobrecarga de Ferro/etiologia , Masculino , Estudos Prospectivos , Qualidade de Vida , Projetos de Pesquisa , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana
15.
Pediatr Blood Cancer ; 64(7)2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27905681

RESUMO

OBJECTIVES: Nationwide prospective cohort study exploring (i) the factors associated with treatment initiation (vs. watchful waiting) in children with primary immune thrombocytopenia (ITP) followed in routine clinical practice and (ii) the predictors of chronicity at 12 months. PROCEDURE: Between 2008 and 2013, 23 centers throughout France consecutively included 257 children aged 6 months-18 years and diagnosed with primary ITP over a 5-year period. Data on ITP clinical features along with medical management were collected at baseline and 12 months. Multivariate logistic regressions were used to determine (i) and (ii) as defined above, providing odds ratio (OR) with 95% confidence interval (95% CI). RESULTS: One hundred thirty-seven (53%) children were males, median age was 4.6 years, median platelet count was 7 × 109/l, and 214 (81%) patients initiated medication. Factors independently associated with treatment initiation included platelet counts <10 × 109/l (P < 0.0001) and mucocutaneous bleeding symptoms at baseline (P < 0.001). At 12 months, data were available for 211 (82%) children, of whom 160 (74%) had recovered. Predictors of chronicity included female gender (OR = 2.2; 95% CI = 1.0-4.8), age ≥10 years (OR = 2.6; 95% CI = 1.1-6.0), and platelet counts ≥10 × 109 /l (OR = 3.2; 95% CI = 1.5-6.9). CONCLUSIONS: In routine clinical practice, the decision to apply a watchful waiting strategy seems to be driven by platelet counts even in the absence of bleeding symptoms, resulting in treatment being initiated in more than 80% of the children surveyed. Overall, younger children with ITP showed good prognosis, with lower platelet counts and, to a lesser extent, male gender predicting more favorable outcomes.


Assuntos
Púrpura Trombocitopênica Idiopática/patologia , Púrpura Trombocitopênica Idiopática/terapia , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Feminino , França , Humanos , Lactente , Masculino , Razão de Chances , Contagem de Plaquetas , Resultado do Tratamento
16.
J Exp Med ; 213(6): 1011-28, 2016 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-27185855

RESUMO

Inherited bone marrow failure syndromes are human conditions in which one or several cell lineages of the hemopoietic system are affected. They are present at birth or may develop progressively. They are sometimes accompanied by other developmental anomalies. Three main molecular causes have been recognized to result in bone marrow failure syndromes: (1) defects in the Fanconi anemia (FA)/BRCA DNA repair pathway, (2) defects in telomere maintenance, and (3) abnormal ribosome biogenesis. We analyzed a patient with mild bone marrow failure and microcephaly who did not present with the typical FA phenotype. Cells from this patient showed increased sensitivity to ionizing radiations and phleomycin, attesting to a probable DNA double strand break (dsb) repair defect. Linkage analysis and whole exome sequencing revealed a homozygous nonsense mutation in the ERCC6L2 gene. We identified a new ERCC6L2 alternative transcript encoding the DNA repair factor Hebo, which is critical for complementation of the patient's DNAdsb repair defect. Sequence analysis revealed three structured regions within Hebo: a TUDOR domain, an adenosine triphosphatase domain, and a new domain, HEBO, specifically present in Hebo direct orthologues. Hebo is ubiquitously expressed, localized in the nucleus, and rapidly recruited to DNAdsb's in an NBS1-dependent manner.


Assuntos
Doenças da Medula Óssea , Núcleo Celular , Códon sem Sentido , DNA Helicases , Homozigoto , Microcefalia , Adolescente , Doenças da Medula Óssea/genética , Doenças da Medula Óssea/metabolismo , Doenças da Medula Óssea/patologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Células Cultivadas , Quebras de DNA de Cadeia Dupla , DNA Helicases/biossíntese , DNA Helicases/genética , Feminino , Regulação da Expressão Gênica , Ligação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Microcefalia/genética , Microcefalia/metabolismo , Microcefalia/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Domínios Proteicos
17.
Blood ; 127(14): 1814-22, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26851292

RESUMO

Stroke risk in sickle cell anemia (SCA), predicted by high transcranial Doppler (TCD) velocities, is prevented by transfusions. We present the long-term follow-up of SCA children from the Créteil newborn cohort (1992-2012) detected at risk by TCD and placed on chronic transfusions. Patients with normalized velocities and no stenosis were treated with hydroxyurea, known to decrease anemia and hemolytic rate. Trimestrial Doppler was performed and transfusions restarted immediately in the case of reversion to abnormal velocities. Patients with a genoidentical donor underwent transplant. Abnormal time-averaged maximum mean velocities (TAMMV) ≥200 cm/s were detected in 92 SCA children at a mean age of 3.7 years (range, 1.3-8.3 years). No stroke occurred posttransfusion after a mean follow-up of 6.1 years. Normalization of velocities (TAMMV < 170 cm/s) was observed in 83.5% of patients. Stenosis, present in 27.5% of patients, was associated with the risk of non-normalization (P< .001). Switch from transfusions to hydroxyurea was prescribed for 45 patients, with a mean follow-up of 3.4 years. Reversion, predicted by baseline reticulocyte count ≥400 × 10(9)/L (P< .001), occurred in 28.9% (13/45) patients at the mean age of 7.1 years (range, 4.3-9.5 years). Transplant, performed in 24 patients, allowed transfusions to be safely stopped in all patients and velocities to be normalized in 4 patients who still had abnormal velocities on transfusions. This long-term cohort study shows that transfusions can be stopped not only in transplanted patients but also in a subset of patients switched to hydroxyurea, provided trimestrial Doppler follow-up and immediate restart of transfusions in the case of reversion.


Assuntos
Anemia Falciforme , Transfusão de Sangue , Circulação Cerebrovascular , Hidroxiureia/administração & dosagem , Acidente Vascular Cerebral , Ultrassonografia Doppler Transcraniana , Anemia Falciforme/diagnóstico por imagem , Anemia Falciforme/fisiopatologia , Anemia Falciforme/terapia , Velocidade do Fluxo Sanguíneo , Feminino , Seguimentos , Humanos , Lactente , Masculino , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/prevenção & controle
18.
Eur J Haematol ; 96(4): 404-8, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26072930

RESUMO

The aim of this study was to test the association between hematological/genetic factors and cerebral vasculopathy in children with sickle cell anemia (SCA). A group with cerebral vasculopathy (VASC) was composed of children who had stroke (n = 6), silent infarct (n = 11), or an abnormal transcranial Doppler (n = 5). Eighty-four patients had neither positive history of stroke or silent infarct, nor abnormal transcranial Doppler (NORM group). An intermediate group (COND; n = 15) was composed of SCA children with a conditional transcranial Doppler. Biological analyses were performed on samples obtained at steady state and before the beginning of any chronic treatment. The comparisons of the three groups demonstrated a protective effect of α-thalassemia against cerebral vasculopathy through its effects on hemoglobin and reticulocyte levels. Moreover, we observed higher frequency of G6PD deficiency in the VASC group compared with the other groups. Our study confirms the key role of α-thalassemia and G6PD status in the pathophysiology of cerebral vasculopathy in SCA children.


Assuntos
Anemia Falciforme/diagnóstico , Transtornos Cerebrovasculares/diagnóstico , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Talassemia alfa/diagnóstico , Anemia Falciforme/sangue , Anemia Falciforme/complicações , Anemia Falciforme/patologia , Transtornos Cerebrovasculares/sangue , Transtornos Cerebrovasculares/complicações , Transtornos Cerebrovasculares/patologia , Criança , Pré-Escolar , Feminino , Deficiência de Glucosefosfato Desidrogenase/sangue , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/patologia , Hemoglobinas/metabolismo , Humanos , Masculino , Contagem de Reticulócitos , Reticulócitos/patologia , Fatores de Risco , Ultrassonografia Doppler Transcraniana , Talassemia alfa/sangue , Talassemia alfa/patologia
19.
Br J Haematol ; 171(4): 615-24, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26205481

RESUMO

The level of circulating platelet-, erythrocyte-, leucocyte- and endothelial-derived microparticles detected by high-sensitivity flow cytometry was investigated in 37 ß-thalassaemia major patients receiving a regular transfusion regimen. The phospholipid procoagulant potential of the circulating microparticles and the microparticle-dependent tissue factor activity were evaluated. A high level of circulating erythrocyte- and platelet-microparticles was found. In contrast, the number of endothelial microparticles was within the normal range. Platelet microparticles were significantly higher in splenectomized than in non-splenectomized patients, independent of platelet count (P < 0·001). Multivariate analysis indicated that phospholipid-dependent procoagulant activity was influenced by both splenectomy (P = 0·001) and platelet microparticle level (P < 0·001). Erythrocyte microparticles were not related to splenectomy, appear to be devoid of proper procoagulant activity and no relationship between their production and haemolysis, dyserythropoiesis or oxidative stress markers could be established. Intra-microparticle labelling with anti-HbF antibodies showed that they originate only partially (median of 28%) from thalassaemic erythropoiesis. In conclusion, when ß-thalassaemia major patients are intensively transfused, the procoagulant activity associated with thalassaemic erythrocyte microparticles is probably diluted by transfusions. In contrast, platelet microparticles, being both more elevated and more procoagulant, especially after splenectomy, may contribute to the residual thrombotic risk reported in splenectomized multi-transfused ß-thalassaemia major patients.


Assuntos
Plaquetas/fisiologia , Transfusão de Sangue , Micropartículas Derivadas de Células/fisiologia , Trombofilia/sangue , Talassemia beta/sangue , Adolescente , Adulto , Autoanticorpos/sangue , Autoanticorpos/imunologia , Plaquetas/ultraestrutura , Micropartículas Derivadas de Células/classificação , Terapia Combinada , Diabetes Mellitus/etiologia , Membrana Eritrocítica/ultraestrutura , Feminino , Hemoglobina Fetal/imunologia , Citometria de Fluxo , Humanos , Hipogonadismo/etiologia , Ferro/sangue , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/etiologia , Masculino , Lipídeos de Membrana/sangue , Pessoa de Meia-Idade , Estresse Oxidativo , Fosfatidilserinas/sangue , Risco , Esplenectomia , Trombofilia/etiologia , Reação Transfusional , Adulto Jovem , Talassemia beta/complicações , Talassemia beta/cirurgia , Talassemia beta/terapia
20.
Blood ; 125(10): 1653-61, 2015 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-25533032

RESUMO

Early transcranial Doppler (TCD) screening of the Créteil sickle cell anemia (SCA)-newborn cohort, and rapid initiation of transfusion programs, resulted in successful prevention of overt strokes, but a high cumulative risk of silent cerebral infarcts (SCI) remained, suggesting that TCD screening does not identify all patients with SCA at risk for SCI. We hypothesized that episodes of hypoperfusion/hypoxia, as observed during acute chest syndromes or acute anemic events (AAE), and extracranial internal carotid artery (eICA) stenoses, detectable via submandibular Doppler sonography and cervical magnetic resonance angiography (MRA), could also be risk factors for SCI. This study includes 189 stroke-free patients with SCA from the Créteil newborn cohort (1992-2010) followed longitudinally by magnetic resonance imaging/MRA, including cervical MRA at the last assessment. All patients with abnormal TCD and/or intracranial stenoses were placed on a transfusion program. Mean follow-up was 9.9 years (range, 2.2-19.9 years; 1844 patient-years). Annual rates of clinical events were calculated. The cumulative risk for SCI was 39.1% (95% confidence interval [CI], 23.5%-54.7%) by age 18 years, with no plateau. We confirm that baseline hemoglobin level lower than 7 g/dL before age 3 years is a highly significant predictive risk factor for SCI (hazard ratio, 2.97; 95% CI, 1.43-6.17; P = .004). Furthermore, we show that AAE rate (odds ratio, 2.64 per unit increase; 95% CI, 1.09-6.38; P = .031) and isolated eICA stenosis (odds ratio, 3.19; 95% CI, 1.18-8.70; P = .023) are significant and independent risk factors for SCI.


Assuntos
Anemia Falciforme/complicações , Anemia/complicações , Estenose das Carótidas/complicações , Infarto Cerebral/etiologia , Doença Aguda , Adolescente , Anemia/sangue , Anemia Falciforme/sangue , Anemia Falciforme/genética , Velocidade do Fluxo Sanguíneo , Artéria Carótida Interna , Estenose das Carótidas/diagnóstico , Estenose das Carótidas/fisiopatologia , Infarto Cerebral/diagnóstico , Criança , Pré-Escolar , Doença Crônica , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Estudos Longitudinais , Angiografia por Ressonância Magnética , Imagem por Ressonância Magnética , Masculino , Fatores de Risco , Adulto Jovem
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