These studies were initiated after publication of a seminal study showing that adenovirus type 5 (HAdV-C5) infection of HeLa cells induces interleukin-8 (CXCL8) expression through a Raf/mitogen-activated protein (MAP) kinase signaling pathway [137], and based on reasoning that CXCL8 expression by infected corneal cells might be responsible for the keratitis seen in EKC. This evidence concerns the gene CXCL8 and epidemic keratoconjunctivitis.