In patients with keratoconjunctivitis (KCS), hypersensitive and inflammatory cytokines, such as IL-17 and IFN-γ, are secreted from the resident intraepithelial lymphocytes and infiltrating CD4+ T cells due to desiccation in the tear film of the ocular surface53–57. The gene discussed is IL17A; the disease is keratoconjunctivitis.