MPO and anti-neutrophil cytoplasmic antibody-associated vasculitis: An induction regimen involving rituximab, a short course of low-dose oral cyclophosphamide, and a rapid prednisone taper was used in 129 patients with ANCA-associated vasculitis (AAV), 70% of whom had myeloperoxidase (MPO)-ANCA and 9% had relapsing disease [27].