Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of systemic vasculitides, that are characterized
by inflammation in the small vessels, ranging from capillaries to arterioles or venules. AAV is divided into three variants
based on the clinical manifestations and histological findings such as microscopic polyangiitis (MPA), granulomatosis with polyangiitis
(GPA) and eosinophilic GPA (EGPA). MPA often induces rapid progressive necrotising glomerulonephritis, and occasionally
induces diffuse alveolar hemorrhage. In contrast, GPA preferentially affects the respiratory tracts from the bronchus to
the nasal cavity. GPA can also involve the kidneys, but the frequency of renal involvement is less than MPA. EGPA is based on
allergic components such as asthma, peripheral eosinophilia, migratory eosinophilic pneumonia and eosinophil infiltration.
Since 1982, when the association between ANCA and systemic vasculitis was first reported, several classification criteria for
AAV have been proposed. This review describes the classification criteria for and nomenclature of AAV from the 1990
American College of Rheumatology (ACR) classification criteria to the 2012 revised Chapel Hill consensus conference (CHCC)
nomenclature of Vasculitides. New classification trials for AAV such as AAV based on the ANCA-types (myeloperoxidase-
ANCA vasculitis, proteinase 3-ANCA vasculitis and ANCA negative vasculitis) and the ACR/European League Against
Rheumatism (EULAR) 2017 provisional classification criteria for GPA were also introduced. In addition, the histopathological
classification of ANCA-associated glomerulonephritis and the revised 2017 international consensus on testing of ANCAs in
GPA and MPA are also discussed.