Anti-neutrophil cytoplasmic antibody-associated systemic vasculitis is a multi-system disease that can present to a number of medical specialties, and where early identification and treatment improves outcome. The vasculitides are commonly divided into WG, MPA, and CSS. This review will revise the common clinical presentations of these diseases and initial investigations. Anti-neutrophil cytoplasmic antibodies have provided a valuable test to aid in diagnosis and there is increasing clinical and experimental evidence that suggests they have an important role in the pathogenesis of disease. Anti-neutrophil cytoplasmic antibodies are directed at either MPO or PR3 which are present in the granules and on the cell surface of neutrophils. They can be detected by indirect immunofluoresence and ELISA-based assay, and both are essential when vasculitis is suspected. The antibodies are able to activate neutrophils and promote injury, and recent data have shown they can directly cause glomerulonephritis and systemic vasculitis in animal models.
Diagnosis of AASV is made using clinical features, ANCA test, and relevant tissue biopsy. Treatment with cytotoxics has transformed the prognosis but until recently there has been limited trial evidence to determine which regime is best. This article will review a range of studies published over the last five years and preliminary evidence from ongoing studies to give an outline of current practice for immunosuppression and monitoring of disease. There is also now a range of biological therapies available including anti-TNF and anti-B-cell antibodies, which may have an increasing role as either adjunctive therapy or new regimes to induce remission.