Blood reviews
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Anemia is present in over two-thirds of patients with malignant hematological disorders. The etiology of anemia predominates from ineffective erythropoiesis from marrow infiltration, cytokine related suppression, erythropoietin suppression, and vitamin deficiency; ineffective erythropoiesis is further exacerbated by accelerated clearance due to antibody mediated hemolysis and thrombotic microangiopathy. As the anemia is chronic in nature, symptoms are generally well tolerated and often non-specific. ⋯ Conservative/restrictive RBC transfusion practices have shown equivalent patient outcomes compared to liberal transfusion practices, and meta-analysis has shown improved in-hospital mortality, reduced cardiac events, re-bleeding, and bacterial infections. The implications for a lower threshold for transfusion in patients with malignancies are therefore increasingly being scrutinized. Alternative management strategies for anemia with IV iron and erythropoietin stimulating agents (ESAs) should be considered in the appropriate settings.
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Exosomes are small (30-150 mm) vesicles secreted by all cell types and present in all body fluids. They are emerging as vehicles for delivery of membrane-tethered signaling molecules and membrane enclosed genes to target cells. ⋯ In hematologic malignancies, exosomes reprogram the bone marrow microenvironment, creating a niche for abnormal cells and favoring their expansion. The molecular and genetic mechanisms exosomes utilize to shuttle information between cells are currently being examined as are the potential roles exosomes play as biomarkers of disease or future therapeutic targets.