TNFSF13B and systemic lupus erythematosus: In particular, we noted increased serum BAFF levels correlated with a rise in anti-DNA antibodies at the time of flare in lupus patients post rituximab.19 We therefore hypothesised that lupus patients treated with belimumab following rituximab therapy will have lower anti-dsDNA antibody levels compared with those that have received rituximab alone, and that this combination would have greater efficacy than rituximab alone.