Significance of antineutrophil cytoplasmic antibody positivity in patients with systemic sclerosis: A single-centre pilot study in Korea

Objective. We investigated whether antineutrophil cytoplasmic antibody (ANCA) positivity at diagnosis may be associated with the cross-sectional clinical features at diagnosis and predicting all-cause mortality during follow-up in Korean patients with systemic sclerosis (SSc). In addition, we assessed the incidence of SSc and ANCA-Associated vasculitis (AAV) overlap syndrome in patients with ANCA positivity. Methods. We retrospectively reviewed the clinical and laboratory features through the medical records of 177 SSc patients who fulfilled the inclusion and exclusion criteria. SSc was classified by the 2013 American College of Rheumatology/European League Against Rheumatism classification criteria. AAV was classified by the 2007 European Medicine Agency algorithms and the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Results. The median age was 52 years, and 23 patients were males. The detection rate of ANCA in Korean patients with SSc was 20.3%. Unlike a previous study, ANCA positivity at diagnosis was significantly associated with neither the cross-sectional clinical and laboratory variables at diagnosis nor the rate of all-cause mortality during follow-up in Korean patients with SSc. However, three female patients (8.3%) with ANCA could be classified as having microscopic polyangiitis (MPA) during follow-up. Conclusion. No significant associations of ANCA positivity with the cross-section clinical features or all-cause mortality during follow-up were observed in this study. But, given that 3 of 36 SSc patients with ANCA were classified as having AAV based on the histological confirmation, we suggest that physicians should consider recommending a biopsy when AAV is strongly suspected in SSc patients with ANCA.