ANCA patterns as identified by confocal microscopy. (A) Classical ANCA (patient 1: diagnosis, Wegener granulomatosis; IIF, cANCA-IgG 1:1024; ELISA, anti-PR3 positive). (B) Perinuclear ANCA (patient 2: diagnosis, microscopic polyangiitis; IIF, pANCA-IgG 1:256; ELISA, anti-MPO positive). (C) Atypical cANCA contained in an intravenous immunoglobulin preparation (preparation E1, IgG titer 1:256). (D) Atypical ANCA (preparation A1, IgG titer 1:1024). A Leica TCS NT confocal light microscope with a 63×/1.32 NA oil PL APO 1.32-0.6 lens was used.