1. Absolute neutrophil count less than 0.5x10e9/Litre, platelets less than 50x10e9/Litre 2. Previous TNF alpha antagonist treatment within the last 3 months 3. Confirmed bacterial sepsis or untreated bacterial, mycobacterial or fungal infection 4. Untreated hepatitis B virus infection 5. Recent major surgery within the last 8 weeks 6. Organ transplant recipients 7. Primary or secondary immunodeficiency 8. History of diverticulitis, inflammatory bowel disease, or other symptomatic gastrointestinal condition that might predispose to bowel perforation 9. Known cirrhosis or aminotransferases greater than 5 times upper limit of normal 10. Pregnant or breastfeeding 11. Known allergy or hypersensitivity to TCZ or other monoclonal antibodies 12. Previous participation in the trial 13. Patient being treated with palliative intent, or not expected to be alive in 48 hours

1. Absolute neutrophil count less than 0.5x10e9/Litre, platelets less than 50x10e9/Litre 2. Previous TNF alpha antagonist treatment within the last 3 months 3. Confirmed bacterial sepsis or untreated bacterial, mycobacterial or fungal infection 4. Untreated hepatitis B virus infection 5. Recent major surgery within the last 8 weeks 6. Organ transplant recipients 7. Primary or secondary immunodeficiency 8. History of diverticulitis, inflammatory bowel disease, or other symptomatic gastrointestinal condition that might predispose to bowel perforation 9. Known cirrhosis or aminotransferases greater than 5 times upper limit of normal 10. Pregnant or breastfeeding 11. Known allergy or hypersensitivity to TCZ or other monoclonal antibodies 12. Previous participation in the trial 13. Patient being treated with palliative intent, or not expected to be alive in 48 hours