A disease-specific activity index for Wegener's granulomatosis: modification of the Birmingham Vasculitis Activity Score. International Network for the Study of the Systemic Vascul... by Stone, J, Hoffman, G, Merkel, P, Min, Y, Uhlfelder, M, Hellmann, D, Specks, U, Allen, N, Davis, J, Spiera, R, Calabrese, L, Wigley, F, Maiden, N, Valente, R, Niles, J, Fye, K, McCune, J, St Clair, E, Luqmani, R