TNFSF13B and systemic lupus erythematosus: We used an anti‐mAPRIL single‐chain monoclonal antibody for specific APRIL inhibition, mBAFFR‐Fc for single BAFF inhibition and mTACI‐Fc, the mouse equivalent of atacicept currently being developed as a treatment for SLE 41, for dual BAFF and APRIL inhibition.