Study of the T CD8 Immune Response in Horton's Disease

Inclusion Criteria: Patients * Patients who have provided written informed consent * Patients covered by national health insurance * Age \> 50 years * Patients with Horton's disease at the diagnosis before any treatment Horton's disease is defined by American College of Rheumatology criteria, the diagnosis is made if any 3 of the following 5 criteria are associated: * age at the onset of the disease 50 years or above * recent onset localised headache * indurated temporal artery or decrease/absence of temporal pulse * erythrocyte sedimentation rate (ESR) above 50 mm for the first hour (or CRP\>20 mg/L) * positive TAB showing vascularitis with infiltration of mononucleated cells or granulomatous inflammation with or without giant cells. Controls Controls will be healthy volunteers recruited from blood donors of Dijon CHU, voluntary hospital personnel (nurses, doctors, laboratory technicians and secretaries) and patients without infectious or inflammatory disease, cancer or auto-immune disease (CRP\<5mg/L) recruited in the department of the investigators at Dijon CHU. They will be matched for age and sex. * Age \> 50 years * Patients covered by national health insurance * who have provided written informed consent to take part * Absence of inflammatory syndrome (CRP\<5 mg /L) Exclusion Criteria: * Any patient not meeting inclusion criteria * Patient treated with corticoids or immunosuppressants in the month preceding inclusion * Patients treated with chemotherapy