Delayed Hemolytic Transfusion Reaction

Delayed Hemolytic Transfusion Reaction is a condition that affects the blood and immune system after a blood transfusion. It happens when the body’s immune system attacks the transfused red blood cells, but this reaction occurs several days to weeks after the transfusion. This causes the breakdown of red blood cells, leading to symptoms like fever, fatigue, and jaundice. The condition can reduce the number of healthy red blood cells, causing anemia and making it harder for the body to carry oxygen. It is important because it can cause discomfort and complications after a transfusion, especially in people who have had multiple transfusions before.

Delayed Hemolytic Transfusion Reaction (DHTR) is an immune-mediated destruction of transfused red blood cells occurring typically 3 to 14 days post-transfusion. It results from a secondary immune response to red blood cell alloantigens, often due to previously sensitized antibodies that were undetectable at the time of transfusion. The core pathology involves extravascular hemolysis primarily in the spleen, mediated by IgG antibodies against donor red cell antigens such as Rh, Kell, or Duffy. Clinically, DHTR presents with fever, anemia, jaundice, and sometimes hemoglobinuria, and can cause significant morbidity in patients with chronic transfusion needs. It is a major concern in patients with sickle cell disease and other hemoglobinopathies due to frequent transfusions and alloimmunization. Recognition and prevention are critical to avoid severe hemolysis and complications.