Which antibody from the MNS antigen system can cause severe transfusion reactions?

In the context of the MNS antigen system, Anti-s is the antibody that is most commonly associated with severe transfusion reactions. This system consists of various antigens, including M, N, S, and s, which can stimulate immune responses when mismatched blood is transfused.

When a patient receives blood that lacks the s antigen and has Anti-s antibodies in their serum, the immune response can be significant. This is because Anti-s can activate complement and lead to hemolysis of the transfused red blood cells, resulting in life-threatening complications such as hemolytic transfusion reactions. The risk of severe reaction increases particularly with Anti-s compared to other antibodies in the MNS system, like Anti-M or Anti-N, which typically cause milder responses.

Understanding the implications of blood group incompatibility is crucial for safe transfusion practices, highlighting why it is paramount to screen for such antibodies before transfusions. This awareness helps ensure that blood products are compatible and minimizes the risk of adverse effects.