Question

Which of the following are mechanisms triggered during a transfusion reaction that lead to the destruction of the donor red blood cells? Check all that apply.

a) Complement activation
b) Antibody-dependent cell-mediated cytotoxicity
c) Clotting factor activation
d) Phagocytosis by macrophages

Answer 1

During a transfusion reaction, complement activation and phagocytosis by macrophages are key mechanisms in the destruction of donor red blood cells, while clotting factor activation is not primarily involved.

Step-by-step explanation:

During a transfusion reaction, several mechanisms lead to the destruction of donor red blood cells (RBCs). The mechanisms triggered include:

• Complement activation: This involves the classical complement cascade, which can lead to inflammatory responses and membrane attack complex (MAC) formation resulting in hemolysis of the RBCs.
• Phagocytosis by macrophages: The RBCs coated with antibodies are recognized by macrophages that then engulf and destroy them
• Antibody-dependent cell-mediated cytotoxicity: This process involves immune cells that destroy the RBCs that have been coated with antibodies.

The activation of clotting factors is not a primary mechanism in the destruction of RBCs during a transfusion reaction. Therefore, the correct mechanisms involved are complement activation and phagocytosis by macrophages. These are examples of Type II hypersensitivity reactions.