Effects of Transfusion of Older Stored Red Cells

The purpose of this study is to determine the effects of transfusion of fresh and stored blood on patients. The investigators hope to test: * whether a similar effect (older stored blood is associated with worse outcomes) is seen in chronically transfused patients with hemoglobinopathies. This patient population will also allow the investigators to test whether iron- chelation therapy is beneficial in this setting. * whether washing or cryopreserving the red blood cells has any effect on this outcome. These findings may explain the immunomodulatory effects of older stored blood in patients and will help us develop safer transfusion products for patients.