- 2. An established diagnosis of systemic necrotizing vasculitis (Wegener's granulomatosus, polyarteritis nodosum (PAN), allergic angiitis granulomatosus (AAG, also known as Churg Strauss syndrome), microscopic polyangiitis (MPA), or overlap syndrome)Temporal arteritis, or mixed cryoglobulinemia or primary central nervous system vasculitis AND failure of corticosteroids and any of the following at least 6 months of oral or IV cytoxan, rituximab, or cellcept. (Failure defined as: a) patients with a high disease activity and involvement of internal organs as measured by increased FFS > 2 and/or BVAS > 20, or b) patients who develop recurrent flares with subsequent progressive organ damage.)