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How can incompatible ABO blood cause a dangerous transfusion reaction?
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Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).
An incompatible ABO blood transfusion triggers a dangerous immune response because the recipientās serum contains pre-existing antibodies that recognize and attack the foreign antigens on the donor's red blood cells.12
When these antibodies bind to the donor cells, they initiate an intravascular hemolytic reaction, a type of cytotoxic reaction where the cells are rapidly destroyed. This process can cause severe harm through several mechanisms:34
- Hemolysis: The destruction of red cells releases hemoglobin into the bloodstream. While small amounts are processed by the body, large quantities can overwhelm the system and damage the kidney tubules.4
- Complement Activation: The antibody-antigen binding can activate the complement system, leading to the formation of a membrane attack complex that ruptures the donor cells.4
- Systemic Complications: This reaction can lead to life-threatening outcomes, including vascular collapse and death.32
To prevent these reactions, medical professionals must ensure strict ABO compatibility through rigorous blood grouping and compatibility testing prior to any transfusion.2