ANCA-positive and ANCA-negative phenotypes of eosinophilic granulomatosis with polyangiitis (EGPA): outcome and long-term follow-up of 50 patients from a single Polish center.

Objectives: The aim of the study was to compare the course of the disease and treatment outcomes in ANCA-positive and ANCA-negative eosinophilic granulomatosis with polyangiitis (EGPA) patients from one Polish tertiary referral centre.

Methods: Retrospective and prospective cohort study carried out on 50 patients treated in our department between 1998 and 2012. EGPA diagnosis was based on the American College of Rheumatology (ACR) criteria.