[Rinshō ketsueki] The Japanese journal of clinical hematology
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Iron is essential for various cellular processes, but an excess of iron may cause organ damage through the production of reactive oxygen species. Therefore, the amount of iron in the body must be strictly controlled. The central regulator of systemic iron homeostasis is hepcidin, which is primarily produced in the liver. ⋯ Mutations in the genes HFE, TFR2, HJV, HAMP (encoding hepcidin), and SLC40A1 (encoding ferroportin) cause hereditary hemochromatosis, whereas mutations in TMPRSS6 (which encodes matriptase 2) cause iron-refractory iron deficiency anemia through the upregulation of hepcidin expression. In chronic anemias, such as β-thalassemia, myelodysplastic syndromes, and aplastic anemia, repeated red blood cell transfusion can cause systemic iron overload. Iron chelation therapy improves the prognosis of patients with such conditions.
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Case Reports
Successful rituximab treatment in an elderly patient with recurrent thrombotic thrombocytopenic purpura.
An 81-year-old man presenting with fever, neurological symptoms, thrombocytopenia, and hemolytic anemia was diagnosed with acquired idiopathic thrombotic thrombocytopenic purpura (TTP). His disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13 (ADAMTS13) activity was <1% and the ADAMTS13 inhibitor titer was 3.2 BU/ml. He received plasma exchange and steroid administration until remission was achieved. ⋯ No severe side effects related to rituximab occurred. Although rituximab has not been approved for TTP in Japan, we report the efficacy and safety of rituximab in an elderly patient with recurrent TTP. We suggest that rituximab therapy should be started as soon as possible for recurrent TTP in patients with high titers of ADAMTS13 inhibitor.
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Inherited bone marrow failure syndromes (IBMFS) are a heterogeneous group of genetic disorders characterized by bone marrow failure, congenital anomalies, and an increased risk of malignancies. Diagnosis is often difficult due to the wide variety of clinical expressions. ⋯ Recently, Japanese groups have identified novel causative genes for DBA, FA and congenital thrombocytopenia by applying whole exome-sequencing. In this review, we will highlight recent studies on DBA, FA and CSA in Japan, which have employed next-generation sequencing technologies to elucidate the genetic etiology of IBMFS.
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Serious issues in current hemostatic treatment of hemophilia A are the requirement for frequent intravenous administrations of factor (F) VIII, FVIII inhibitor development, and hemostatic treatment for patients with this inhibitor. For the purpose of overcoming these challenges, the FVIIIa-substituting bispecific antibody against FIXa/FX (ACE910, INN emicizumab) was produced. Emicizumab demonstrated marked hemostatic effects on both ongoing and spontaneous joint bleeding in the acquired hemophilia A primate model. ⋯ The t1/2 was approximately 30 days, and bleeding events were significantly decreased by weekly subcutaneous administration in severe hemophilia A patients, independently of the presence of the inhibitor. Currently, the phase 1/2 extension study is ongoing. We anticipate that emicizumab will show the benefits of prophylactic efficacy with subcutaneous administration at a much lower frequency.
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Chimeric antigen receptor (CAR) is the generic name for synthetic T cell receptors redirected to tumor-associated antigens. Most CARs consist of an ectodomain (scFv or ligand), a hinge region, a transmembrane domain, and signaling endodomains derived from one or two co-stimulatory molecules (CD28, 4-1BB, etc) and from a CD3-ζ chain. CD19-targeted CAR T cell therapy has achieved major success in the treatment of B cell malignancies. ⋯ CD19 CAR T cell therapy from allogeneic donors including third party donors is a potential option for B-cell malignancies. CAR T cell therapies for myeloma, acute myeloid leukemia, and T-cell leukemia are still under development. Our group is currently preparing a phase I study of CD19 CAR T cell therapy in pediatric and young adult patients with ALL using a non-viral gene transfer method, the piggyBac-transposon system.