INTERNATIONAL CONSENSUS ON ANCA TESTING BEYOND SYSTEMIC VASCULITIS
- Jan Willem Cohen Tervaert, Canada
Abstract
Background and Aims
ANCA positivity is a distinctive laboratory feature of ANCA-associated vasculitis. However, ANCA can be detected by antigen-specific immunoassays or indirect immunofluorescence (IIF) in patients with other autoimmune, inflammatory, infectious or neoplastic diseases. The aim was to issue a Consensus Statement on ANCA testing and interpretation beyond systemic vasculitis.
Methods
This Consensus Statement was prepared by a group of experts, including specialists in internal medicine, rheumatologists, nephrologists, gastroenterologists, hepatologists, pulmonologists, and clinical laboratory immunologists, based on the results of a comprehensive search in PubMed for disorders that can be associated with positive ANCA test results.
Results
Evidence suggests that ANCA may have diagnostic, clinical, and/or diagnostic relevance beyond systemic vasculitis. Testing for proteinase-3 ANCA and myeloperoxidase-ANCA should be performed in any patient with clinical features suggesting ANCA-associated vasculitis and in patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis complicated by nephritis, whereas routine ANCA testing is not recommended in connective tissue diseases, autoimmune liver diseases, inflammatory bowel diseases, infections, and/or various forms of malignancy. ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1, who do not have conventional disease-related autoantibodies, or in patients with inflammatory bowel diseases in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn’s disease. In these cases, ANCA should be tested by IIF since target antigens are not yet well characterized
Conclusions
ANCA testing is clinically relevant not only in patients with manifestations suggesting systemic vasculitis, but also in patients with certain other disorders, particularly in patients with anti-GBM disease or idiopathic interstitial pneumonia.