Fig. 1.

The changing classification of AAV (adapted from Watts et al [20].). A single cohort of 99 patients with AAV (from Lane et al [4].) were assigned diagnostic labels using a the American College of Rheumatology 1990 criteria [15], b the Chapel Hill Consensus Conference definitions [16] and c the EMEA algorithm [20]. WG Wegener’s granulomatosis, CSS Churg-Strauss syndrome, MPA microscopic polyangiitis, PAN polyarteritis nodosa