In KCs, TREM1 promotes the release of pro-inflammatory cytokines and chemokines, such as interleukin-1β (IL-1β), IL-6, (C-C motif) ligand 2 (CCL2), CCL5, and interferon γ inducible protein-10 (CXCL10) [15,24]. Here, TREM1 is linked to dry eye syndrome.