Despite recent advances in the treatment of antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV), relapse remains common and patients often experience a variable clinical course after initial treatment. New biomarkers are needed to aid the management of these complex diseases. Discoveries regarding the pathogenesis of AAV, from the importance both of activated B and T cells and the alternative complement pathway to genomic data, may lay the groundwork for identification of novel biomarkers.