Patient description: A 57-year-old man was admitted to the clinic because of weight loss and persistent dry cough 4 months ago. Chest computed topography showed bilateral multiple infiltrates in the upper lobes and thickened bronchial walls. There is a documented positive serum MPO-ANCA in his medical record. Transbronchial biopsy revealed necrotic granulomas with multinucleated giant cells and the Wegener's granulomatosis was diagnosed for him. He is treating with corticosteroid and cyclophosphamides since 4 months ago. His Birmingham Vasculitis Activity Score (BVAS) is above 4 since the beginning of his disease. His last physical exam and lab study was performed yesterday and showed the results bellow: A wellbeing, well-nourished man, non-icteric, cooperative and alert Weight: 73 kg Height: 177 BP: 120/80 HR: 90/min RR: 22/min Hgb: 13 g/dl WBC: 8000 /mm3 (Neutrophil: 2700/mm3) Plt: 300000 /ml AST: 40 U/L ALT: 56 U/L Alk P: 147 U/L Bill total: 1.2 mg/dl ESR: 120 mm/hr MPO-ANCA: 153 EU

Clinical trial eligibility criteria: eligible ages (years): 7.0-999.0,  Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss) Giant Cell Arteritis Granulomatosis With Polyangiitis (Wegener's) Microscopic Polyangiitis Polyarteritis Nodosa Takayasu's Arteritis Diagnostic for Giant Cell Arteritis Age at disease onset >50 years (required) 1. New onset or new type of localized pain in the head 2. Temporal artery abnormality (i.e. temporal artery tenderness to palpation or decreased pulsation, unrelated to arteriosclerosis of cervical arteries) 3. ESR of >40mm in the first hour by the Westergren method 4. Abnormal artery biopsy (i.e. temporal artery biopsy showing vasculitis characterized by a predominance of mononuclear cell infiltration or granulomatous inflammation, usually with multinucleated giant cells) 5. Large Vessel Vasculitis (LVV) by angiogram or biopsy not explained by something else 2. Diagnostic for Takayasu's Arteritis 1. Age at disease onset <50 years 2. Claudication of extremities 3. Decreased brachial artery pulse (one or both arteries) 4. Blood pressure difference of >10mm Hg between the arms 5. Bruit over subclavian arteries or aorta 6. Arteriogram abnormalities compatible with TAK (includes conventional dye angiography or MR angiography or CT angiography) 3. Diagnostic for Polyarteritis Nodosa Major (not explained by other causes) felt by investigator to be due to vasculitis 1. Arteriographic abnormality 2. Presence of granulocyte or mixed leukocyte infiltrate in an arterial wall on biopsy 3. Mononeuropathy or polyneuropathy Minor (not explained by other causes) felt by investigator to be due to vasculitis 1. Weight loss > 4 kg 2. Livedo reticularis, cutaneous ulcerations, or skin nodules 3. Testicular pain or tenderness 4. Myalgias 5. Diastolic blood pressure > 90 mm Hg 6. Elevated BUN or serum creatinine levels 7. Ischemic abdominal pain Isolated cutaneous Polyarteritis Nodosa 1. Biopsy-proven cutaneous PAN 4. Diagnostic for Granulomatosis with Polyangiitis (Wegener's) (GPA) and Microscopic Polyangitis (MPA) Diagnosis of GPA or MPA. Widely accepted diagnostic as opposed to classification or definitions, have not been developed for GPA & MPA For diagnosis of GPA meets at least 2 of the following 5 modified ACR 1. Nasal or oral inflammation with oral ulcers or nasal discharge with pus or blood 2. Abnormal chest radiograph with nodules, fixed infiltrates, or cavities 3. Urinary sediment with microhematuria or red cell casts 4. Granulomatous inflammation within the wall of an artery or in the perivascular area on biopsy 5. Antineutrophil cytoplasmic antibody (ANCA) positive by enzyme immunoassay for either PR3 or MPO-ANCA For diagnosis of MPA, meets the Chapel Hill Consensus Conference Definition for MPA: 1. Necrotizing vasculitis, with few or no immune deposits, that affects small vessels (i.e., capillaries, venules, arterioles) 2. Necrotizing arteritis involving small and medium-sized arteries may be present 3. Necrotizing glomerulonephritis is very common 4. Pulmonary capillaritis often occurs 5. Diagnostic for Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss) 1. Asthma 2. Peak peripheral blood eosinophilia of >10% of total WBC 3. Peripheral neuropathy attributable to vasculitis 4. Transient pulmonary infiltrates on chest imaging studies 5. Paranasal sinus abnormalities or nasal polyposis 6. Eosinophilic inflammation on tissue biopsy If patients have 4 of the above 6 but lack clearcut documentation of small vessel vasculitis, they are also eligible for enrollment. General  Inability to give informed consent and to sign the consent form Enrolled in VCRC protocols 5502, 5503, 5504, 5505, 5506, 5522, or 5523 Unwilling to provide blood for DNA collection