[Rinshō ketsueki] The Japanese journal of clinical hematology
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Inherited bone marrow failure syndromes (IBMFS) are caused by mutations in genes associated with DNA repair and telomere maintenance. In addition, mutations in ribosome-related genes cause defective hematopoiesis. Patients with IBMFS exhibit a predisposition to developing hematological malignancy or solid tumor because of the defect in cellular and molecular hemostasis. ⋯ Recently, monocytopenia and mycobacterial infection (MonoMAC) syndrome with the GATA2 gene mutation have been reported as PID related to bone marrow failure. Patients with MonoMAC syndrome often develop MDS and acute myeloid leukemia. Here, we present the pediatric-onset IBMFS and/or PID with cancer predisposition and briefly discuss the tumorigenesis in each monogenic disease.
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Imatinib, nilotinib, dasatinib, bosutinib, and ponatinib are tyrosine kinase inhibitors used to treat chronic myeloid leukemia (CML). Therapeutic drug monitoring (TDM) and target concentration intervention (TCI) are novel strategies that use concentration-controlled dosing (CCD) to attain a faster and more profound clinical response in patients with CML. The target plasma trough concentration (C0) of imatinib is 1,000 ng/ml to obtain a higher major molecular response (MMR) rate. ⋯ Approaches for these four TKIs involve the use of TCI with specific target concentrations rather than TDM with a therapeutic range. Conversely, for dasatinib, a lower C0 of <4.33 ng/ml is the maximum toxic concentration recommended to avoid pleural effusion. Therefore, precision dosing using CCD of TKIs for CML could maximize the clinical benefit and minimize toxicity.
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Although immune thrombocytopenia (ITP) and thrombotic thrombocytopenic purpura (TTP) appear similar, their symptoms differ. The number of domestic patients diagnosed with ITP and TTP annually has been estimated to be around 24,000 and 400, respectively. Moreover, no major differences in the incidence rate, age of onset, and prognosis have been observed between Europe, the United States (US), and Japan. ⋯ Meanwhile, TTP was designated as an intractable disease in Japan in 2015, and the first clinical practice guidelines were published in 2017. A single-arm study involving rituximab was conducted on high-risk patients in whom treatment with five plasma exchanges was ineffective or ADAMTS13 inhibitor was >2 BU/ml. Approval for the new indication of rituximab for acquired TTP is expected in 2019.
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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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Review Case Reports
Myelodysplastic syndrome with myelofibrosis in which azacitidine therapy was effective and cord blood transplantation was carried out.
Myelodysplastic syndrome with myelofibrosis (MDS-F) is a disease with a poor prognosis, and patients with this condition are at an increased risk of engraftment failures after allogeneic hematopoietic stem cell transplantation (SCT). Azacitidine (AZA) is effective in high-risk MDS patients. However, the effects of AZA on MDS-F have not been elucidated. ⋯ He developed acute graft versus host disease (GVHD) of the skin (stage 3/grade II), but it could be controlled using prednisolone. Chronic GVHD was not observed and he was discharged in good general condition on day 68. While treatment prior to allogeneic SCT of MDS-F has not been established, in the present case, the hematological improvement brought about by AZA likely contributed to the patient's positive response to UCBT.