Final answer:
ABO incompatibilities can be fatal due to agglutination, complement activation, and antibody-dependent cell-mediated cytotoxicity, all of which can cause an immune response leading to hemolysis, organ failure, and death.
Step-by-step explanation:
ABO incompatibilities can be fatal due to a combination of several immune reactions. When a person receives a transfusion of mismatched blood, for example, if a person with type B blood receives type A blood, their body generates an immune response against the A antigens on the transfused red blood cells (RBCs). Three key mechanisms are involved in this reaction:
- Antibodies against the foreign blood type antigens lead to agglutination, where the RBCs clump together and block blood vessels.
- The bound antibodies activate the complement cascade, which is a series of protein reactions that culminate in cell lysis, releasing haemoglobin and causing hemolysis.
- The immune response can involve antibody-dependent cell-mediated cytotoxicity (ADCC), where immune cells are directed to kill the transfused RBCs.
The combination of these reactions results in a severe response that can lead to shock, organ failure, and death. Therefore, the correct answer is D) All of the above.