Disease heterogeneity in antineutrophil cytoplasmic antibody-associated vasculitis: implications for therapeutic approaches.

In recent decades, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis has transformed from an almost uniformly fatal disease to a treatable form of primary systemic vasculitis. Substantial disease heterogeneity exists within ANCA-associated vasculitis and the increasing understanding of this heterogeneity has implications for guiding treatment decisions. Approaches to induction and maintenance therapy vary depending on disease severity, clinical manifestations, and patient-specific factors. In this narrative Review, we examine how disease heterogeneity in ANCA-associated vasculitis, with respect to disease severity, clinical presentations, and ANCA specificity, influences therapeutic decision making. Many questions regarding therapeutic strategies in ANCA-associated vasculitis remain unanswered, and these should guide future research in this complex group of diseases.