Final answer:
The M antigen has an antithetical relationship with the ABO blood group, which is important for blood transfusion compatibility and understanding immune responses in transfusion medicine.
Step-by-step explanation:
An antithetical relationship exists between the M antigen and the ABO blood group. This means that the presence of M antigen is inversely related to certain antigens in the ABO blood group system. The ABO blood group consists of four types: A, B, AB, and O, characterized by the presence or absence of specific antigens - A and B - on the surface of red blood cells.
While the M antigen is part of the MNS blood group system, which is separate from the ABO and Rh systems, the presence of antigens such as antigen A or antigen B from the ABO system can affect the expression of M antigen. This interplay between antigens is relevant when considering compatibility for blood transfusions and understanding immune reactions in transfusion medicine.