ANCA-small vessel vasculitides: what have we (not yet) learned from animal models?

Anti-neutrophil cytoplasmic autoantibodies (ANCA) with a specificity for myeloperoxidase or proteinase 3 are closely associated with small vessel vasculitides (SVV). In vitro, ANCA activate primed neutrophils to release toxic substances that destroy endothelial cells, suggesting a pathogenic role for these autoantibodies in disease development. However, to study the complex interplay between ANCA, neutrophils, and the local environment in vivo, animal models are required. Here, we will review the animal models developed for ANCA-SVV and discuss how these models have been applied to study ANCA-SVV pathogenesis. In addition, some directions for future research pertaining to unresolved issues relevant for the pathogenesis and immunogenesis of ANCA-SVV are proposed.