Anti-endothelial cell antibodies in immune mediated vasculitis(non infectious) are associated with autoreactive ________ activation.

• A. T cells
• B. B cells
• C. Macrophages
• D. NK cells

Answer: (A)

Anti-endothelial cell antibodies contribute to endothelial activation, but the key process they’re linked with in immune-mediated, noninfectious vasculitis is the activation of autoreactive T cells. When endothelial cells are targeted by autoantibodies, they upregulate adhesion molecules and MHC, increasing the visibility of self-antigens to T cells. This promotes presentation of self-derived peptides to autoreactive T cells, especially CD4+ and CD8+ populations, driving their activation. Activated autoreactive T cells then release cytokines that recruit and activate macrophages and other inflammatory cells, producing the vascular injury characteristic of vasculitis. B cells play a role by producing the autoantibodies, but the tissue-damaging force in this scenario is the autoreactive T cell–driven response. NK cells are not the primary mediators in this context.