S100A9 and dry eye syndrome: Unique DEGs not previously associated with SS were HLA-DRB3, CFI, CEACAM1, CXCL1, DUSP4, IL19, IL1R1, MUC1, SERPING1, S100A8, S100A9, PIGR, XBP1, although some proteins encoded by these DEGs have been associated with dry eye [XBP1, HL-A-DR (11, 33, 115)]. The majority of these DEGs participate in Innate immune response.