CD4 and Keratoconjunctivitis sicca: There are previous reports indicating that dry eye-related ocular surface inflammation is mediated by lymphocytes and conjunctival inflammation represented by T cell infiltrates and overexpression of CD3, CD4, and CD8; lymphocyte activation markers CD11a and HLA-DR and proinflammatory cytokines, like interleukin IL-1β, IL-6, IL-8, TNF-alpha, and matrix metalloproteinases (MMPs) mainly MMP-9 are also involved in the pathogenesis of dry eye [13].