A patient with a hemoglobin of 6.2 g/dL who receives type AB blood is likely to experience which hypersensitivity reaction?

The situation described involves a patient receiving an incompatible blood type transfusion, specifically type AB blood when the patient likely has a different blood type. In this case, the most relevant hypersensitivity reaction is Type 2 hypersensitivity.

Type 2 hypersensitivity, also known as cytotoxic hypersensitivity, occurs when antibodies produced by the immune system target and destroy the body's own cells or foreign cells. When a patient receives mismatched blood, their immune system may recognize the donor red blood cells as foreign because they carry different antigens. This recognition leads to an immune response where antibodies bind to the transfused red blood cells, activating complement and triggering an inflammatory response. This can result in hemolysis (destruction of red blood cells), which can cause further complications such as hemoglobinuria, kidney failure, and other systemic reactions.

Understanding the mechanism of Type 2 hypersensitivity is crucial in transfusion medicine, as it underscores the importance of careful blood typing and cross-matching prior to transfusions to prevent these adverse reactions.