Anti-neutrophil cytoplasmic antibodies (ANCAs) are antibodies against antigens in the cytoplasm of neutrophil granulocytes (the most common type of white blood cell). They are detected as a blood test in a number of autoimmune disorders, but are particularly associated with systemic vasculitis.

Types

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There are two types, depending on the pattern of staining on light microscopy:

• pANCAs (perinuclear staining) - against myeloperoxidase; lactoferrin; elastase; catepsin G - in Churg-Strauss syndrome, microscopic polyangiitis and various other diseases
• cANCAs (cytoplasmic staining) - against proteinase 3 - mainly in Wegener's granulomatosis

Pathophysiology

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The exact reason why people develop ANCAs is unknown. It is assumed that ANCAs act by causing release of lytic enzymes from the white blood cells (Falk et al 1990), causing inflammation of the blood vessel wall (vasculitis).

History

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ANCAs were originally described in Davies et al in 1982 in segmental necrotising glomerulonephritis, and by van der Woude et al in 1985 in Wegener's. The Second International ANCA Workshop, held in The Netherlands in May 1989, fixed the nomenclature on perinuclear vs. cytoplasmic patterns, and the antigens MPO and PR3 were discovered in 1988 and 1989, respectively (Jennette et al 1990).

References

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• Davies DJ, Moran JE, Niall JF, Ryan GB. Segmental necrotising glomerulonephritis with antineutrophil antibody: possible arbovirus aetiology. Brit Med J 1982;285:606. PMID 6297657.
• Falk RJ, Terrell RS, Charles LA, Jennette JC. Anti-neutrophil cytoplasmic autoantibodies induce neutrophils to degranulate and produce oxygen radicals in vitro. Proc Natl Acad Sci U S A 1990;87:4115-4119. PMID 2161532.
• Jennette JC, Hoidal JR, Falk RJ. Specificity of anti-neutrophil cytoplasmic autoantibodies for proteinase 3. Blood 1990;75:2263-4. PDF (2 MB). PMID 2189509.
• van der Woude FJ, Rasmussen N, Lobatto S, Wiik A, Permin H, van Es LA, van der Giessen M, van der Hem GK, The TH. Autoantibodies against neutrophils and monocytes: tool for diagnosis and marker of disease activity in Wegener's granulomatosis. Lancet 1985;1(8426):425-9. PMID 2857806.

Immunology | Chemical pathology | Medical tests

ANCA | Anticorps antineutrophiles cytoplasmatiques | Antineutrofiele cytoplasmatische antistoffen