Which type of antibodies is associated with a shoulder of risk for graft rejection?

The association of graft rejection risk with anti-HLA class I antibodies is rooted in their role in the immune response. HLA class I molecules are present on almost all nucleated cells and are essential for the recognition of self versus non-self. When a graft is transplanted, the recipient's immune system can recognize the donor's HLA class I molecules as foreign if they are sufficiently different from its own. This recognition leads to the activation of T cells and other immune mechanisms aimed at eliminating what the body perceives as an invader, thus contributing significantly to the risk of acute and chronic graft rejection.

Anti-HLA class II antibodies, while also associated with graft rejection, are primarily involved in activating helper T cells and often play a more indirect role in graft rejection compared to class I antibodies. Non-HLA antibodies can be involved in non-specific injury mechanisms and are not directly tied to the classical pathways of rejection. Neutralizing antibodies are typically specific to certain pathogens or cytokines and have a different role in the immune response that does not directly correlate with graft rejection. Therefore, the direct impact of anti-HLA class I antibodies on graft survival makes this the most relevant type of antibody in terms of rejection risk.