Transcriptional and Immune Parameters of Response to Belimumab

The study will involve 80 adult patients diagnosed with SLE who will be started on belimumab (standard approved dose of i.v. 10 mg/kg or subcutaneous 200 mg/week) due to active disease. The intention to start belimumab will be made by the treating Rheumatologist(s), in accordance to the current standard of care, and on the basis of shared physician-patient decision making.