View clinical trials related to Sickle Cells Disease.
Filter by:Sickle cell disease (SCD) is a worldwide distributed hereditary red cell disorder, which affects approximately 75,000 individuals in the United States and almost 20,000- 25,000 subjects in Europe, this latter mainly related to the immigration fluxes from endemic areas such as Sub-Saharian Africa to European countries. Studies of global burden disease have pointed out the invalidating impact of SCD on patient quality of life. This requires the development of new therapeutic options to treat sickle cell related acute and chronic complications. SCD is caused by a point mutation in the β-globin gene resulting in the synthesis of pathological hemoglobin S (HbS). HbS displays peculiar biochemical characteristics, polymerizing when deoxygenated with associated reduction in cell ion and water content (cell dehydration), increased red cell density and further acceleration of HbS polymerization. Pathophysiological studies have shown that dense, dehydrated red cells play a central role in acute and chronic clinical manifestations of SCD, in which intravascular sickling in capillaries and small vessels leads to vaso-occlusion and impaired blood flow with ischemic/reperfusion injury. In microcirculation, vaso-occlusive events (VOC) result from a complex and still partially known scenario, involving the interactions between different cell types, including dense red cells, reticulocytes, abnormally activated endothelial cells, leukocytes, platelets and plasma factors. Target organs, such as bone or lung, are involved in both acute and chronic clinical manifestations of SCD, related to their peculiar anatomic organization mainly characterized by sluggish circulation and relative local hypoxia. VOCs combined with marrow hyperplasia and inflammation has been suggested to contribute to the development of sickle bone disease (SBD). Recently, it has been proposed a possible role of vitamin D deficiency in SBD, which appears to be subordinated to the primary defect in bone homeostasis. In a humanized mouse model for SCD, we recently reported that SBD is due to imbalance between osteoblast/osteoclast activity induced by recurrent VOCs. In addition, we show that zoledronic acid prevents bone impairment related to SCD, reducing osteoclast activity and improving osteoblast performance.
Streptococcus pneumoniae is the major cause of bacterial infection in patients with sickle cells disease. The 23-valent pneumococcal polysaccharide vaccine (PSV) is supposed to be poorly immunogenic in these patients. We want to evaluate whether a prime with a 13-valent pneumococcal conjugate vaccine (PCV), able to induce immunologic memory, would improve the immune response against SP polysaccharides (SPP). Primary objective: To evaluate and compare the specific antibody response to a prime-boost vaccine strategy combining PCV prime at W0 followed by the administration of PSV boost at W4, to the administration of PSV alone at W4 in patients with sickle cells disease. Secondary objectives: Evaluation and comparison of the specific antibody response to the thirteen pneumococcal serotypes shared by the PCV and PSV vaccines, 4 weeks after the single PSV vaccination for patients from Group 1 or 4 weeks after the boost PSV vaccination for patients from group 2. Evaluation of the duration of the specific antibody response at W24 and 96. Evaluation of the T CD4 lymphocyte response to the CRM 197 protein. Safety of the vaccines. Study Design: Randomised, monocentric, controlled phase II study of the immunological efficacy of a prime boost strategy combining the sequential administration of the PCV and PSV, compared to the administration of the PSV alone. 180 adults patients with sickle cells disease will be included. The primary endpoint : proportion of responders at W8 to at least 10 of thirteen serotypes. Secondary endpoints : Proportion of responders at W8 according to 4 categories of responders: 5-7; 3-4; 2-1 and 0. Evaluation of the pneumococcal opsonophagocytic activity (OPA) at baseline and W8 for each serotype, defined as the proportion of patients with OPA > 1:8 geometric mean of the specific antibody titers proportion of patients who experienced an increase of specific antibody levels 1 g/ml. Evaluation of the priming effect of the PCV vaccine in the group 1. Duration of the specific antibody responses at week 24 and W96. CD4 T lymphocyte responses to the CRM 197 protein (proliferative and cytokine production) at weeks 0, 8 and 12. Safety of the vaccines frequency of Streptococcus pneumoniae infections. Statistical Considerations: With a sample size of 180 patients, and a randomization ration of 1:1, the study will have a power of at least 90% to show a difference of 25% category between the group receiving PCV and PSV vs the group receiving PSV alone (two-sided type I error = 5%). The primary comparison between both groups will be performed using a Chi2 test for independent groups or a Fisher exact test where appropriate.