Preferential localization of CD8(+) alpha(E)beta(+)(7) T cells around acinar epithelial cells with apoptosis in patients with Sjogren's syndrome

The T lymphocytes that infiltrate the exocrine glands in Sjogren's syndrome (SS) play a key role in damaging glandular epithelial cells, but the mecha nisms of this damage by T lymphocytes are not fully understood. To determin e the cellular basis of this phenomenon, we focused our attention on the T lymphocytes around acinar epithelial cells in SS. We showed that CD8(+) but not CD4(+) T lymphocytes were located around the acinar epithelial cells a nd that a majority of these CD8(+) T lymphocytes possess an unique integrin , alpha(E)beta(7) (CD103). The acinar epithelial cell adherent with alpha(E )beta(7) (CD103) + CD8(+) T lymphocytes was apoptotic. Both the perforin/gr anzyme B and Fas/Fas ligand pathways were implicated in the process of prog rammed cell death In lacrimal glands. These results suggested that alpha(E) beta(7) integrin, by interacting with E-cadherin, mediates the adhesion bet ween CD8(+) T lymphocytes and acinar epithelial cells in SS and participate s in inducing epithelial cell apoptosis, leading to secretory dysfunction o f exocrine glands, a hallmark of SS.