Hemoglobin, the oxygen-carrying molecule in a red blood cell, contains iron. The body has limited ways to store and remove iron. When red blood cells (RBCs) die, they are consumed by macrophages. Transfused RBCs have shorter lifespans that native ones, so they die and are consumed more frequently by the macrophages, which causes the latter to die from excess iron which is then released into the blood. Therefore, with frequent blood transfusions, iron builds up in the body over time. This can enter the liver, heart, pancreas, and endocrine organs. Free iron increases the production of oxygen radicals (mostly hydroxyl radicals) that cause damage to cells (particularly their DNA).
Transfusion hemosiderosis
Post-transfusion purpura
Cold autoimmune hemolytic anemia
Transfusion-dependent anemia
Iatrogenic anemia
Acute hemolytic transfusion reaction
Hemolysis
Mechanical hemolytic anemia