IRF9 and systemic lupus erythematosus: LDGs exhibited the highest ISG activity in SLE PBMCs, ISG expression was associated with PLSCR1, TCF4, IRF9 and STAT1, prominent granulocyte infiltration was observed in kidneys of a murine lupus model (MRL/lpr mice), decreasing significantly after treatment with avacopan (a selective inhibitor of the C5a receptor).