Immunological basis and management of Hemolytic transfusion reactions
Blood transfusion is a form of transplantation in which whole blood or blood cells from one individual are transferred intravenously into the circulation of a host. Blood transfusion are most often performed to replace blood lost by hemorrhage or to correct defect caused by inadequate production of blood cells. The major barrier to successful blood transfusion is the immune response to cell surface molecules that is different between individuals. The most important alloantigen system in blood transfusion is the ABO system. ABO antigens is represented by virtually all cells including red blood cells. Individuals lacking particular blood group antigen produce natural IgM antibodies against the antigen. If the individual are given blood cells expressing the target antigen, the preexisting antibodies binds to the transfused cells activate complements and cause transfusion reactions.
Hemolytic Transfusion reaction is an adverse reaction associated with transfusion of blood products; transfusion reaction may be acute or delayed (chronic). Acute transfusion those temporarily associated with transfusion of blood products and takes place within 24 hours of transfusion while Delayed transfusion occur 3–10 days after the transfusion of RBC products that appear to be serologically compatible. These reactions occur in patients who have been alloimmunized to minor RBC antigens during previous transfusions. Acute hemolytic transfusion reaction is a potentially fatal transfusion reaction and can be either due to immune and nonimmune mechanisms. Immune mediated acute hemolytic transfusion reactions result from infusion of red blood cells that are incompatible with the patient’s anti-A, anti-B, or other red blood cell antibodies and Typically causes intravascular hemolysis presenting with sudden onset fever or chills, so it is important to monitor patient during transfusion and stop the transfusion immediately if there is any change in vital signs or unexpected signs. In severe reactions cardiovascular, renal and respiratory support. Non-immune acute hemolytic transfusion occur when red blood cells are destructed by factors other than antibodies. Patient at risk for delayed hemolytic or serological transfusion reaction include those with a history of red blood cell antibodies, Delayed hemolytic transfusion reaction is usually due to anmnestic immune response to a foreign antigen on donor RBCs (most commonly Rh or other minor blood group antigens) previously encountered by recipient Typically causes extravascular hemolysis and The most prominent clinical features include dark urine or jaundice followed by fever chest or abdominal pain and hypertension. Most patient do not require treatment other than additional transfusion to maintain desired hemoglobin.