TNFSF13B and systemic lupus erythematosus: Despite this lack of success, belimumab, a monoclonal antibody that neutralizes the soluble B-cell activation and survival factor BAFF, has recently been approved for SLE patients with active disease in the USA and Europe by the Federal Drug Administration (FDA) and the European Medicines Agency after successful phase III clinical trials showing modest improvements in disease (47, 48).