An evaluation of ANCA in vasculitis and non-vasculitis diseases

Purpose: The present study aims to evaluate the existence of anti-neutrophil cytoplasmic antibody (ANCA) in vasculitis and non-vasculitis diseases. Materials and methods: Over five years, the results of 5107 serum samples submitted to the Medical Microbiology Laboratory for ANCA evaluation were retrospectively analyzed. The existence of ANCA was studied using the preparations containing ethanol-fixed and formalin-fixed granulocyte substratum by indirect immunofluorescence (IIF) testing method; and myeloperoxidase (MPO) and Proteinase-3 (PR-3) antigens in ANCA-positive samples were studied with the ELISA method. Results: 422 (8.3%) of the samples were considered ANCA-positive. 62 (19.9%) of the 312 patients diagnosed with vasculitis and 360 (7.5%) of the 4795 patients with non-vasculitis were ANCA-positive. ANCA-positivity was found 16.7% in patients with IgA vasculitis, 18.6% in leukocytoclastic vasculitis, 56.9% in rheumatoid arthritis, 46.9% in systemic lupus erythematosus, 18.6% in interstitial pulmonary disease, 7.7% multiple sclerosis, 10.2% in chronic renal failure, and 5.1% in cerebrovascular accident. Conclusion: In vasculitis cases, ANCA positivity rate was higher than in non-vasculitis diseases. In non-vasculitis diseases, the target antigen MPO-ANCA and PR3-ANCA positivity was rare compared to vasculitis cases. Among ANCA-positive patients, the most common non-vasculitis diseases included connective tissue disease, chronic renal failure and interstitial pulmonary disease.