[Rinshō ketsueki] The Japanese journal of clinical hematology
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Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease in which platelets are consumed and thrombotic microangiopathy develops in multiple organs due to a severe deficiency of the metalloproteinase, ADAMTS13. TTP should be suspected in any case associated with thrombocytopenia and hemolytic anemia; TTP can be diagnosed in cases of profound reduction in ADAMTS13 activity (to <10% of the normal level). ⋯ Rituximab was recently approved in Japan for use in refractory or relapsing TTP. Likewise, caplacizumab, an anti-von Willebrand factor, may contribute to disease control and overall survival by preventing ongoing thrombosis and acute end-organ damage.
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Hepcidin is a key molecule that regulates iron metabolism in the body. Iron refractory iron deficiency anemia (IRIDA) is a genetic disorder caused by a defect in the TMPRSS6 gene encoding matriptase-2, a transmembrane serine protease that physiologically inhibits hepcidin production. In patients with IRIDA, the iron uptake in the intestine is remarkably reduced, and iron deficiency anemia (IDA) develops. ⋯ Due to the malabsorption of iron in the intestine, IRIDA is refractory to oral iron supplementation, but partially responds to parenteral iron administration. A high hepcidin level gives IRIDA a lot of similarities with anemia of chronic disease, and a differential diagnosis between the two disorders needs careful inspection. Diagnosis of IRIDA needs genetic testing that is hardly available in most facilities, and therefore its clinical features are not fully understood.