Final answer:
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.