p-ANCA

Perinuclear Anti-Neutrophil Cytoplasmic Antibodies (p-ANCA) show a specific staining pattern (perinuclear) on neutrophils in indirect immunofluorescence (IIF). This pattern is often associated with antibodies against Myeloperoxidase (MPO), commonly seen in microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA/Churg-Strauss), and sometimes primary sclerosing cholangitis or ulcerative colitis. Confirmation with specific MPO antibody test is usually required.