Antibodies, Monoclonal, Humanized; Arterial Occlusive Diseases/prevention & control; Receptors, Interleukin-6/antagonists & inhibitors; Takayasu Arteritis; Tumor Necrosis Factor-alpha/antagonists & inhibitors; Adolescent; Adult; Antibodies, Monoclonal, Humanized/administration & dosage; Antibodies, Monoclonal, Humanized/adverse effects; Arterial Occlusive Diseases/etiology; Arterial Occlusive Diseases/immunology; Biological Therapy/methods; Cyclophosphamide/administration & dosage; Cyclophosphamide/adverse effects; Disease Progression; Drug Monitoring; Drug Resistance; Female; Follow-Up Studies; Humans; Immunosuppressive Agents/administration & dosage; Immunosuppressive Agents/adverse effects; Magnetic Resonance Angiography/methods; Male; Prednisone/administration & dosage; Prednisone/adverse effects; Retrospective Studies; Severity of Illness Index; Takayasu Arteritis/complications; Takayasu Arteritis/drug therapy; Takayasu Arteritis/epidemiology; Takayasu Arteritis/immunology; Takayasu Arteritis/physiopathology; Time Factors; Treatment Outcome; United Kingdom/epidemiology