C-ANCA pattern on indirect immunofluorescence

Demonstration of cytoplasmic antineutrophil cytoplasmic autoantibodies (C-ANCA) by indirect immunofluorescence with normal neutrophils. There is heavy staining in the cytoplasm while the multilobulated nuclei (clear zones) are nonreactive. These antibodies are usually directed against proteinase 3 (PR3), and most patients have granulomatosis with polyangiitis (GPA).