TNFSF13B and kidney disorder: The EULAR guidelines note that belimumab (an inhibitor of B-lymphocyte stimulator (BLys)) can be used in extra-renal disease if there is inadequate control despite first line treatment.2 Rituximab is an anti-CD20 monoclonal antibody that depletes B lymphocytes and, despite negative results of randomised controlled trials, can be used off label in patients with severe renal or extra-renal disease refractory to other agents.2 Rituximab became publicly funded in New Zealand for use in SLE in 2014 but belimumab is not yet available.