Clinical impact of proteinase 3-antineutrophil cytoplasmic antibody positivity in eosinophilic granulomatosis with polyangiitis

BACKGROUND/AIMS: This study investigated the clinical implication of proteinase 3 (PR3)-antineutrophil cytoplasmic antibody (ANCA) in Korean patients with eosinophilic granulomatosis with polyangiitis (EGPA). METHODS: Among the 242 patients with ANCA-associated vasculitis identified from the hospital database, 49 patients with EGPA were selected and analysed in this study. Demographic, clinical, and laboratory data at diagnosis were reviewed to compare the features of patients with PR3-ANCA and without, as well as the clinical outcomes of relapse and end-stage renal disease (ESRD) during the follow-up period. The outcomes of patients with PR3-ANCA and without were compared by using the Kaplan-Meier survival analysis. RESULTS: The median age of the patients was 54 years, 17 (34.7%) were male, and six (12.2%) patients had PR3-ANCA at baseline. The most common items of the 1990 American College of Rheumatology criteria for EGPA were sinusitis (95.9%) and asthma (or asthmatic history) (93.9%). During the follow-up, none died, eight experienced relapse and two progressed to ESRD. EGPA patients with PR3-ANCA exhibited peripheral eosinophilia less frequently than those without (50.0% vs. 88.4%, p = 0.047). On the other hand, EGPA patients with PR3-ANCA experienced relapse more often compared to those without (50.0% vs. 11.6%, p = 0.047), and the cumulative relapse-free survival rate was lower compared to those without PR3-ANCA (p = 0.012). CONCLUSIONS: EGPA patients possessing PR3-ANCA at disease diagnosis had distinct clinical feature and outcome compared to those without PR3-ANCA. These results should be taken into account in the management of patients with EGPA.