284. RITUXIMAB VERSUS CYCLOPHOSPHAMIDE FOR CENTRAL NERVOUS SYSTEM INVOLVEMENT OF ANCA-ASSOCIATED VASCULITIS: A RETROSPECTIVE STUDY. (29th March 2019) - Hajj-Ali, Rula; Baqir, Misbah; Krishna, Rachana; Giacomi, Federica; Kumar, Neeraj; Kalina, Peter; Specks, Ulrich