Efficacy and Safety of Tocilizumab in Adult's Still Disease

Inclusion Criteria: * Patients must have been diagnosed with adult-onset Still's disease according to the criteria of Yamaguchi (at least 5 criteria in total, including at least 2 major criteria), although these criteria do not have to be present at the time of inclusion in the study. Major criteria are:Fever ≥39°C for at least 1 week,Arthralgia lasting at least 2 weeks,Maculo-papular, non-pruritic skin rash,Leucocytosis .≥10,000/mm³) including ≥80% neutrophils;Minor criteria are:Pharyngitis or sore throat,Lymphadenopathy or splenomegaly,Liver enzyme (transaminase) abnormalities,Negative for rheumatoid factor or antinuclear antibodies * Patients aged \>18 * Capable of signing informed consent Exclusion Criteria: * active infections (especially sepsis and Epstein-Barr virus), * malignant disease (especially lymphomas), * other autoimmune or inflammatory disease (especially polyarteritis nodosa) * patients will be required to restrict other treatments for Still's disease to low-dose corticosteroids +/- non steroidal anti inflammatory drugs for at least the first 4 weeks of the study. * pregnant or breast-feeding women * women of childbearing potential unwilling to use adequate contraception and not become pregnant during the course of the study * previous treatment with other biologic antirheumatic agents will require a washout period before inclusion * history of listeriosis or latent or active tuberculosis * persistent chronic or active recurring infection requiring treatment with antibiotics, antivirals, or antifungals within 4 weeks prior to the screening visit, or history of frequent recurrent infections unacceptable per investigator judgment. * received administration of any live (attenuated) vaccine within 3 months prior to the inclusion visit * known history of Human Immunodeficiency Virus antibody; and/or positive Hepatitis B surface antigen , and/or positive Hepatitis C antibody at the screening visit. * history of recurrent herpes zoster. * history of prior articular or prosthetic joint infection * history of a hypersensitivity reaction, other than localised injection site reaction , to any biological molecule * uncontrolled diabetes * patients under dialysis * presence of any of the following laboratory abnormalities at the screening visit: haemoglobin \<8.5g/l, WBC \<3000/μL, platelet count \<150,000/μL, neutrophils \<1500/μL * AST or ALT \>2 Upper limit and bilirubin \>2 Upper limit