The translation of TNF-α blockade (i.e., infliximab and etanercept) into a therapy for ANCA-associated GN (ANCA GN), including patients with granulomatosis with polyangiitis (GPA) (PR3-ANCA) and microscopic polyangiitis (MPO-ANCA), has faced challenges. Here, MPO is linked to microscopic polyangiitis.