Criteria for the Regression of Pediatric Mastocytosis: A Long-Term Follow-Up

International audienceMastocytosis is a neoplastic condition characterized by the accumulation of mast cells (MCs) in 1 or more organ. Adults tend to have persistent, systemic mastocytosis, whereas MC infiltration in children is usually limited to the skin and typically regresses after several years. Both adults and children could display mast cell activation symptoms (MCASs) due to MC mediator release. In more than 85% of both adult and pediatric cases, KIT mutations are present, with the KIT D816V mutation being present in most affected adults but in only half the affected children

iPSCs derived from infertile men carrying complex genetic abnormalities can generate primordial germ-like cells

International audienceAbstract Despite increasing insight into the genetics of infertility, the developmental disease processes remain unclear due to the lack of adequate experimental models. The advent of induced pluripotent stem cell (iPSC) technology has provided a unique tool for in vitro disease modeling enabling major advances in our understanding of developmental disease processes. We report the full characterization of complex genetic abnormalities in two infertile patients with either azoospermia or XX male syndrome and we identify genes of potential interest implicated in their infertility. Using the erythroblasts of both patients, we generated primed iPSCs and converted them into a naive-like pluripotent state. Naive-iPSCs were then differentiated into primordial germ-like cells (PGC-LCs). The expression of early PGC marker genes SOX17 , CD-38 , NANOS3 , c-KIT , TFAP2C , and D2-40 , confirmed progression towards the early germline stage. Our results demonstrate that iPSCs from two infertile patients with significant genetic abnormalities are capable of efficient production of PGCs. Such in vitro model of infertility will certainly help identifying causative factors leading to early germ cells development failure and provide a valuable tool to explore novel therapeutic strategies

Preclinical Evaluation of Efficacy and Safety of an Improved Lentiviral Vector for the Treatment of β-Thalassemia and Sickle Cell Disease

A previously published clinical trial demonstrated the benefit of autologous CD34+ cells transduced with a self-inactivating lentiviral vector (HPV569) containing an engineered β-globin gene (βA-T87Q globin) in a subject with β-thalassemia major. This vector has been modified to increase transduction efficacy without compromising safety. In vitro analyses indicated that the changes resulted in both increased vector titers (3 to 4 fold) and increased transduction efficacy (2 to 3 fold). An in vivo study in which 58 β-thalassemic mice were transplanted with vector- or mock-transduced syngenic bone marrow cells indicated sustained therapeutic efficacy. Secondary transplantations involving 108 recipients were performed to evaluate long-term safety. The six month study showed no hematological or biochemical toxicity. Integration site (IS) profile revealed an oligo/polyclonal hematopoietic reconstitution in the primary transplants and reduced clonality in secondary transplants. Tumor cells were detected in the secondary transplant mice in all treatment groups (including the control group), without statistical differences in the tumor incidence. Immunohistochemistry and quantitative PCR demonstrated that tumor cells were not derived from transduced donor cells. This comprehensive efficacy and safety data provided the basis for initiating two clinical trials with this second generation vector (BB305) in Europe and in the USA in patients with β-thalassemia major and sickle cell disease