Vasculitis Definitive diagnosis of 1 of the following forms: Churg-Strauss syndrome Giant cell arteritis Henoch-Schonlein purpura Hypersensitivity vasculitis Polyarteritis nodosa Takayasu arteritis Wegener's granulomatosis Evidence of active disease defined as reversible manifestations of the underlying inflammatory process Must have 1 or more of the following: Elevated Westergren erythrocyte sedimentation rate Elevated C reactive protein Decrease serum complement levels Evidence of potential life threatening involvement of at least 1 internal organ system Endocardial and/or myocardial disease Central nervous system disease Pulmonary parenchymal disease Renal disease defined as WHO III, IV or V and a high activity and low chronicity index Immune mediated cytopenias Refractory to conventional therapy (i.e., failed or relapsed within 6 months) after attempts to control disease with at least 2 drugs, including prednisone and 1 of the following: Methotrexate Azathioprine Cyclophosphamide Cyclosporine OR Controlled on conventional therapy but at price of unacceptable toxicity