Patients with dry eye often have higher levels of pro-inflammatory cytokines in their tears (27), such as Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-8 (IL-8), and MMP-9 (28). The gene discussed is CXCL8; the disease is Keratoconjunctivitis sicca.