Myeloperoxidase and anti-MPO IgG synergistically enhance TLR9-mediated immune activation in ANCA-associated vasculitis.

MPO and anti-MPO IgG work together to significantly boost TLR9-driven immune activation in ANCA-associated vasculitis, with complexing DNA amplifying this effect.

• Why it matters: Understanding the mechanisms behind ANCA pathogenicity is crucial because current knowledge mainly focuses on neutrophil activation, leaving gaps in how immune responses are amplified in vasculitis.
• What they did: The study used biochemical and cellular approaches to show that MPO binds extracellular DNA, and anti-MPO IgG promotes its uptake into immune cells, enhancing TLR9 activation with both bacterial and self-DNA in murine and human cells.
• The result: This cooperative mechanism explains how MPO and anti-MPO IgG facilitate immune sensing of extracellular DNA, providing insights into potential therapeutic targets for controlling inflammation in vasculitis.