Desiccating stress induces T cell-mediated Sjögren's syndrome-like lacrimal keratoconjunctivitis

Chronic dry eye syndrome affects over 10 million people in the United States; it is associated with inflammation of the lacrimal gland (LG) and in some cases involves T cell infiltration of the conjunctiva. We demonstrate that environmental desiccating stress (DS) elicits T cell-mediated inflammation of the cornea, conjunctiva, and LG, but not other organs in mice. The lacrimal keratoconjunctivitis (LKC) was mediated by CD4⁺ T cells, which, when adoptively transferred to T cell-deficient nude mice, produced inflammation in the LG, cornea, and conjunctiva, but not in any other organ. Adoptively transferred CD4⁺ T cells produced LKC even though recipients were not exposed to DS. LKC was exacerbated in euthymic mice depleted of CD4 ⁺CD25⁺forkhead/winged helix transcription factor ⁺ regulatory T cells. The results suggest that DS exposes shared epitopes in the cornea, conjunctiva, and LG that induce pathogenic CD4 ⁺ T cells that produce LKC, which under normal circumstances is restrained by CD4⁺CD25⁺forkhead/winged helix transcription factor⁺ regulatory T cells.