ANCA Associated Vasculitis Subtypes: Recent Insights and Future Perspectives

Abstract

Keziah Austin,1,* Shalini Janagan,2,* Matthew Wells,3 Helena Crawshaw,4 Stephen McAdoo,5 Joanna C Robson2,6 1Department of Rheumatology, Royal National Hospital for Rheumatic Diseases, Bath, UK; 2Department of Rheumatology, Bristol Royal Infirmary, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK; 3Department of Rheumatology, North Bristol NHS Trust, Bristol, UK; 4Department of Rheumatology, Gloucestershire Hospitals NHS Foundation Trust, Gloucester, UK; 5Department of Medicine, Imperial College London, London, UK; 6Faculty of Health and Applied Sciences, University of the West of England, Bristol, UK*These authors contributed equally to this workCorrespondence: Keziah Austin, Department of Rheumatology, Royal National Hospital for Rheumatic Diseases, Bath, UK, Email [email protected]: The ANCA associated vasculitides (AAVs) affect a range of internal organs including ear nose and throat, respiratory tract, kidneys, skin and nervous system. They include granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and microscopic polyangiitis (MPA). The AAVs are treated with high dose glucocorticoids, immunosuppressants, and targeted biological medications. Since the 1990s classification criteria for the AAVs have been based on clinical features, laboratory tests and basic imaging; an initiative to update the classification criteria incorporating newer tests, for example, anti-neutrophil cytoplasmic antibodies (ANCA) and novel imaging techniques will be published this year. There is also evidence for classification of patients based on ANCA subtype; those with anti-proteinase 3 antibodies (PR3) or anti-myeloperoxidase antibodies (MPO) have differences in response to treatment and clinical outcomes. An update is described within this review. The pathogenesis of AAV involves necrotizing inflammation of small to medium blood vessels involving multiple immunological pathways. We present an update on emerging evidence related to auto-antibodies, complement and lymphocyte pathways. This review describes emerging treatment regimens, including evidence for plasma exchange in severe disease and the inhibitor of the complement C5a receptor (C5aR) inhibitor, Avacopan. Lastly, patient reported outcomes are key secondary outcomes in randomised controlled trials and increasingly clinical practice, we report development in disease specific and glucocorticoid-specific PROs.Keywords: vasculitis, pathogenesis, patient-reported outcomes, epidemiology

Keywords

• vasculitis
• pathogenesis
• patient-reported outcomes
• epidemiology