Anti-neutrophil cytoplasmic antibodies (ANCA) are autoantibodies that target neutrophil and monocyte cytoplasmic components. 1982 Davies et al.[1]ANCA was found in the sera of patients with segmental necrotizing glomerulonephritis, 1985 van der Woude et al.[2]cytoplasmic ANCA (cANCA) was found in patients with granulomatosis with polyangiitis (GPA), 1988 Falk and Jennette[3]perinuclear ANCA (pANCA) was reported in the sera of patients with systemic vasculitis and primary necrotizing crescent glomerulonephritis. Subsequently, the investigators used ELISA to find that myeloperoxidase (MPO) was the main target antigen of pANCA, and proteinase 3 (PR3) was confirmed as the main target antigen of cANCA in GPA patients[3,4,5,6]。 In addition to the common MPO and PR3, ANCA target antigens include human leukocyte elastase (HLE), lactoferrin (LF), lysozyme (LYS), cathepsin G (Cath G) and bactericidal/permeability increasing protein (BPI), etc. As a biomarker of small vessel vasculitis, ANCA mainly exists in patients with ANCA-associated vasculitis (AAV), such as microscopic polyangiitis (MPA), GPA and eosinophilic granulomatosis with polyangiitis (EGPA), and may also exist in other autoimmune diseases such as inflammatory bowel disease and autoimmune liver disease, as well as malignant diseases, infectious diseases and drug-induced vasculitis. The detection of ANCA and its specific autoantibodies in clinical laboratory has important clinical significance in the diagnosis, differential diagnosis, classification, disease monitoring and prognosis of related diseases[7,8,9,10]。
