Inclusion Criteria:  Adult subject (≥ 18 years old), male or female Patient with systemic lupus according to ACR 1997 criteria Patient followed by the National Reference Center "Rare Systemic Autoimmune Diseases" of the University Hospitals of Strasbourg Patient who agreed to be vaccinated against SARS-CoV-2 Subject having expressed his non-opposition to the research Subject affiliated to a social health insurance protection scheme  Exclusion Criteria:  Patient treated by:  Corticosteroids (> = 10mg / day) Immunosuppressant (azathioprine, mycophenolate mofetil, cyclophosphamide) to control lupus activity A biomedicine targeting B cells (rituximab, belumimab). Inability to provide informed information about the subject (subject in an emergency, difficulty in understanding the subject, etc.) Subject under safeguard of justice Subject under guardianship