What is the pathophysiology of acute hemolytic transfusion reactions?

Updated: Jan 02, 2019
  • Author: S Gerald Sandler, MD, FACP, FCAP; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Acute hemolytic transfusion reactions may be either immune-mediated or nonimmune-mediated. Immune-mediated hemolytic transfusion reactions caused by immunoglobulin M (IgM) anti-A, anti-B, or anti-A,B typically result in severe, potentially fatal complement-mediated intravascular hemolysis. Immune-mediated hemolytic reactions caused by IgG, Rh, Kell, Duffy, or other non-ABO antibodies typically result in extravascular sequestration, shortened survival of transfused red cells, and relatively mild clinical reactions. [15]

Acute hemolytic transfusion reactions due to immune hemolysis may occur in patients who have no antibodies detectable by routine laboratory procedures. [16] Experimental evidence supports a central role for cytokines in the pathophysiology of hemolytic transfusion reactions. Tumor necrosis factor appears to be the most commonly identified mediator of intravascular coagulation and end-organ injury but other cytokines have also been implicated, including interleukin (IL)-8, monocyte chemoattractant protein, and IL-1 receptor antagonist. [17, 18]

Nonimmune hemolytic transfusion reactions occur when red blood cells (RBCs) are damaged before transfusion, resulting in hemoglobinemia and hemoglobinuria without significant clinical symptoms. [19]


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