What is the primary cause of hyperacute transfusion reactions?

• A. ABO incompatibility
• B. Febrile reactions
• C. Anaphylaxis due to IgA deficiency
• D. Delayed hemolysis

Answer: (C)

Hyperacute transfusion reactions are primarily caused by ABO incompatibility. This type of reaction occurs almost immediately after the transfusion begins, typically within minutes. It is due to the recipient's antibodies reacting against the donor red blood cells that have incompatible ABO antigens. The immediate immune response leads to rapid hemolysis of the transfused blood cells, which can cause severe complications, including shock and renal failure.

While anaphylaxis due to IgA deficiency can happen in some transfusion scenarios, it is not the primary cause of hyperacute reactions. This form of reaction is generally linked to hypersensitivity to donor proteins, particularly in individuals with IgA deficiency who may have developed antibodies against IgA. However, this is not as immediate or as widespread as a hyperacute reaction resulting from ABO incompatibility.

Febrile reactions are typically a response to white blood cell antigens and manifest with fever and chills but do not cause rapid hemolysis. Delayed hemolysis, on the other hand, results from different mechanisms and occurs days to weeks post-transfusion, hence does not fall under the category of hyperacute reactions.

In summary, the characteristic of hyperacute transfusion reactions being triggered by ABO incompatibility highlights the critical importance of blood type matching