045. EVALUATION OF NOVEL SERUM BIOMARKERS OF DISEASE ACTIVITY IN GIANT CELL ARTERITIS, TAKAYASU'S ARTERITIS, POLYARTERITIS NODOSA, AND EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS. (29th March 2019) - Rodriguez-Pla, Alicia; Warner, Roscoe; Cuthbertson, David; Carette, Simon; Khalidi, Nader; Koening, Curry; Langford, Carol; McAlear, Carol; Moreland, Larry; Pagnoux, Christian; Seo, Philip; Specks, Ulrich; et al.