S100A9 and systemic lupus erythematosus: Similar results were also obtained coincidentally in the lymph nodes, where mice that received S100A9−/−-MDSCs showed markedly reduced activation of B cells (Supplementary Fig. 9A, B) and CD4+ T cells (Supplementary Fig. 9C, D) as well as decreased percentage of germinal center B cells (Supplementary Fig. 9E, F) and plasmacytes (Supplementary Fig. 9G, H) in the mLNs of IMQ-induced lupus mice.