LYN and systemic lupus erythematosus: To determine whether G‐CSF contributes to the pathogenesis of lupus in Lyn−/− mice, we generated Lyn−/−G‐CSF−/− mice that were aged to 36 weeks and assessed alongside age‐matched C57BL/6 controls and single‐mutant Lyn−/− and G‐CSF−/− mice for hallmarks of inflammation and pathology.