Mariane de Montalembert

Gene Therapy in a Patient with Sickle Cell Disease.

Abstract Sickle cell disease results from a homozygous missense mutation in the β‐globin gene that causes polymerization of hemoglobin S. Gene therapy for patients with this disorder is complicated by the complex cellular abnormalities and challenges in achieving effective, persistent inhibition of polymerization of hemoglobin S. We describe our first patient treated with lentiviral vector–mediated addition of an antisickling β‐globin gene into autologous hematopoietic stem cells. Adverse events were consistent with busulfan conditioning. Fifteen months after treatment, the level of therapeutic antisickling β‐globin remained high (approximately 50% of β‐like–globin chains) without recurrence of sickle crises and with correction of the biologic hallmarks of the disease. (Funded by Bluebird Bio and others; HGB‐205 ClinicalTrials.gov number, NCT02151526.)

Acute clinical events in 299 homozygous sickle cell patients living in France

Abstract: A subset of 299 patients with homozygous sickle cell anaemia, enrolled in the cohort of the French Study Group on sickle cell disease (SCD), was investigated in this study. The majority of patients were children (mean age 10.1±5.8 yr) of first generation immigrants from Western and Central Africa, the others originated from the French West Indies (20.2%). We report the frequency of the main clinical events (mean follow‐up 4.2±2.2 yr). The prevalence of meningitis‐septicaemia and osteomyelitis was, respectively, 11.4% and 12% acute chest syndrome was observed in 134 patients (44.8%). Twenty patients (6.7%) developed stroke with peak prevalence at 10–15 yr of age. One hundred and seventy‐two patients (58%) suffered from one or more painful sickle cell crises, while the others (42.5%) never suffered from pain. The overall frequency of acute anaemic episodes was 50.5%, (acute aplastic anaemia 46%; acute splenic sequestration 26%). A group of 27 patients were asymptomatic (follow‐up >3 yr).

Delayed hemolytic transfusion reaction in children with sickle cell disease.

Background Transfusion is a cornerstone of the management of sickle cell disease but carries a high risk of hemolytic transfusion reaction, probably because of differences in erythrocyte antigens between blood donors of European descent and patients of African descent. Patients may experience hemolytic transfusion reactions that are delayed by from a few days to two weeks and manifest as acute hemolysis (hemoglobinuria, jaundice, and pallor), symptoms suggesting severe vaso-occlusive crisis (pain, fever, and acute chest syndrome), and profound anemia, often with reticulocytopenia. This case-series study aims to describe the main characteristics of this syndrome, to discuss its pathophysiology, and to propose a management strategy. Design and Methods We identified 8 pediatric cases of delayed hemolytic transfusion reactions between 2006 and 2009 in the database of the Necker Hospital, France. All patients had received cross-matched red cell units compatible in the ABO, RH, and KEL systems. We reviewed the medical charts in the computerized blood transfusion databases. All patients were admitted to the intensive care unit. We progressively adopted the following strategy: intravenous immunoglobulins, and darbopoietin alpha when the reticulocyte count was below 150×109/L, without further blood transfusion during the acute episode unless absolutely necessary. Results The median time between the transfusion and the diagnosis of delayed hemolytic transfusion reaction was six days. All patients had severe bone pain; all but one had a high-grade fever. Five patients had hemoglobin levels less than than 4g/dL and 3 had reticulocytopenia. In 5 patients, no new antibody was found; one patient had weakly reactive antibodies. Only 2 patients had new allo-antibodies possibly responsible for the delayed hemolytic reaction. Conclusions The initial symptoms of delayed hemolytic transfusion reaction were complex and mimicked other complications of sickle cell disease. In most of our cases, no new antibody was identified, which underlines the complexity of the pathophysiology of this syndrome.

Complications and treatment of patients with β-thalassemia in France: results of the National Registry

Background β-thalassemia is a rare disease in France, encountered mainly in patients originating from Italy and North Africa. In the setting of the recent French plan for rare diseases, a National Registry for thalassemia has been developed since 2005. Epidemiological and clinical data have been collected on living patients with β-thalassemia major or intermedia, including those who underwent hematopoietic stem cell transplantation. Design and Methods A standardized questionnaire was sent to clinicians throughout the national professional networks involved in the management of thalassemic patients and data were updated every 18 months. A cross-sectional study was performed in February 2009. Results Data on 378 patients (267 with thalassemia major) with a median age of 20 were recorded. Hematopoietic stem cell transplantation was performed in 52 patients. Stature, rates of parenthood, splenectomy, and cholecystectomy were no different between non-transplanted thalassemia major and thalassemia intermedia patients, after adjustment for age. Among the 215 non-transplanted thalassemia major patients, the median serum ferritin level was 1240 ng/mL and the rates of iron-related complications were 10%, 6%, 10% and 48% for cardiac failure, diabetes, hypothyroidism, and hypogonadism, respectively. From 2005 to 2008, a dramatic switch in chelation treatment, from deferoxamine to deferasirox, was observed. Conclusions The rates of complications of iron overload in French thalassemia major patients appeared similar to those reported in other developed countries in which this condition is not endemic. There were no significant differences in height and parenthood rates between patients with the major and the intermedia forms of the disease, underlining the progress in clinical care. Future developments will focus on mortality and morbidity under oral chelation treatment.

Autologous Blood Donation for Elective Surgery in Children Weighing 8–25 kg

To determine whether autologous blood donation can be used safely and efficiently in children weighing 8–25 kg, we studied children whose perioperative blood losses were expected to exceed 25% of total blood volume. Blood donations were performed in pediatric units, under the direction of an anesthesiologist and a blood bank physician experienced in pediatric care. Twenty‐four children, median age 6 years (1–13), were included. They underwent surgery mainly for digestive or urological disorders, and for orthopedic defects. Forty blood collections were performed of the 46 prescribed. Phlebotomies could not be performed in 1 child because of the mothers apprehension, and in 5 cases because of venous access problems. All phlebotomies were hemodynamically well tolerated. Hemodilution was also performed in 17 children, and cell saver used in 2. Allogeneic blood transfusion was avoided in 21/24 children.

Decreased transfusion needs associated with hydroxyurea therapy in Algerian patients with thalassemia major or intermedia.

BACKGROUND: Studies of evolution of transfusion requirements in thalassemic patients treated with hydroxyurea have produced somewhat conflicting results, especially in patients with thalassemia major. Our aims were to determine the proportion of good responders to hydroxyurea in a population of transfusion‐dependent thalassemic patients and to identify the factors associated with a decrease of transfusion needs.

Dose of desferrioxamine and evolution of HIV-1 infection in thalassaemic patients.

To study the relationship between the dose of desferrioxamine (DFX) and the progression of the HIV‐1 disease in thalassaemia major patients (TMP), 64 seropositive TMP patients were studied. Cumulative incidence of CDC stage IV was calculated using a non‐parametric life‐table method. The association with the mean daily dose of DFX was tested with a Cox proportional hazards model which was also used to adjust for confounding variables. The median of the mean daily dose of DFX over the seropositive period was 40mg/kg (range 0‐65mg/kg). Age at seroconversion (P < 0.02) and splenectomy (P < 0.03) were found to be associated with the mean daily dose of DFX. 6.5 years after seroconversion, 11% of those who had been prescribed more than 40mg/kg of DFX daily had entered stage IV versus 35% of those who had been prescribed a lower dose (P < 0.01). When the dose was taken as a continuous variable it was found that the rate of progression was significantly smaller in TMP receiving a higher dose (P < 0.002). even after adjusting for age and splenectomy (P < 0.02). Although it should be noted that these results were obtained in an observational study, possibly biased by a non‐random allocation of the DFX dose, we believe that they are striking enough to support the claim that the role of DFX in the progression of HIV disease should be further evaluated.

Acute splenic sequestration crisis in sickle cell disease: cohort study of 190 paediatric patients

Acute splenic sequestration crisis (ASSC) is an unpredictable life‐threatening complication of sickle cell disease (SCD) in infants. Here, our objective was to update available clinical information on ASSC. We retrospectively studied the 190 patients who were diagnosed at birth with SS or Sbeta0 in the Paris conurbation between 2000 and 2009 and who experienced ASSC. They had 437 ASSC episodes (0·06/patient‐year). Median age at the first episode was 1·4 years (0·1–7) and 67% of patients had more than one episode. Age was the only factor predicting recurrence: the risk was lower when the first episode occurred after 2 years versus before 1 year of age (hazard ratio, 0·60; 95% confidence interval, 0·41–0·88; P = 0·025). A concomitant clinical event was found in 57% of episodes. The mortality rate was 0·53%. The treatment consisted in watchful waiting without prophylactic blood transfusions or splenectomy in 103 (54%) patients and in a blood transfusion programme in 55 (29%) patients. Overall, splenectomy was performed in 71 (37%) patients, at a median age of 4·5 years (range, 1·9–9·4). In conclusion, aggressive treatment may be warranted in patients experiencing ASSC before 2 years of age. Randomized controlled trials are needed to define the best treatment modalities.

Relationship between vitamin D deficiency and bone fragility in sickle cell disease: A cohort study of 56 adults

BACKGROUND Recent studies suggest that patients with sickle cell disease (SCD) have profound vitamin D (VD) deficiency. Limited data exist on the effect of VD deficiency on bone fragility in these patients. OBJECTIVES To assess the prevalence of VD deficiency in adults with SCD and its consequences on bone metabolism and fragility. METHODS This prospective study included 56 SCD adult patients (mean age 29.8 ± 9.5 years), in a clinically steady state. Clinical and laboratory data were recorded. Bone mineral density (BMD) was measured using dual X-ray absorptiometry. Fracture history, BMD, avascular osteonecrosis, H-shaped vertebra and markers of mineral metabolism were compared between two groups of patients presenting very low (≤ 6 ng/mL, n=26) (group 1) and low (>6 ng/mL, n=26) (group 2) 25(OH)D concentration, respectively. RESULTS Median 25(OH)D concentration was 6 ng/mL. VD deficiency (25(OH)D <10 ng/mL) was found in 42 out of 56 patients (75%) and secondary hyperparathyroidism in 40 (71.4%). History of fracture was documented in 17 patients (30.3%), osteopenia and/or osteoporosis in 39.6% of patients. Overall, patients of group 1 were more likely to have sustained a fracture (42.8%) compared to patients of group 2 (17.8%) (p=0.04). These patients had also lower body mass index and significantly higher parathyroid hormone, C-terminal telopeptides of type I-collagen and bone-specific alkaline phosphatase serum levels. There was no difference between group for BMD, avascular osteonecrosis history, H-shaped vertebra, and disease severity markers. CONCLUSION This study suggests that VD deficiency is a key feature in SCD-bone disease. It is highly prevalent and associated with hyperparathyroidism, bone resorption markers, and history of fracture. The optimal supplementation regimen remains to be determined.

Epidemiological and clinical study of sickle cell disease in France, French Guiana and Algeria

Abstract: The main clinical and haematological features of sickle cell patients were compared in 618 French, 50 Guianese and 87 Algerian patients. In homozygous sickle cell patients, the proportion of icteric subjects rises with age in all centres; the prevalence of splenomegaly reaches a peak in children from 1 to 5 years and then decreases; jaundice and splenomegaly are more often noted in Algerian and Guianese than French patients. The prevalence of painful crisis is comparable in the 3 centres. In 465 French SS children, having a mean age of 7.3 ± 5.9 years, the prevalence of a past history of meningitis is 7.3%, of septicaemia 4.1% of osteomyelitis 8.8%. These percentages do not differ significantly between countries. Prevalence of a past history of cerebrovascular accident is 3.2% in French SS patients; 1.2% in SC, 3.8% in Sβ thalassaemia. A past history of acute splenic sequestration was noted significantly more often in SS (11.75%) and Sβ thalassaemia (14.3%) than SC (3.6%) in French children (p < 0.05). Proportions of subjects transfused at least once do not differ between countries; SS children are more transfused (64%) than SC (15.6%) and Sβ thalassaemic (66%) (p < 10–4). Haemoglobin and reticulocyte counts do not differ significantly between countries. In conclusion, no major differences were detected between French, Guianese and Algerian homozygous sickle cell patients: this may be due to the fact that France is in itself a mosaic of ethnic origins.