CD4 and dry eye syndrome: Aire -/- mice experience spontaneous organ-specific lymphocytic and mononuclear infiltration of the eye and lacrimal gland that causes a SS-like aqueous-deficient dry eye phenotype where IFN gamma-secreting CD4 T cells serve as the primary effectors and cooperate with local IL-1/IL-1 receptor signaling pathways to induce aqueous tear deficiency and ocular surface disease [21–23].