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Background: We have previously shown aberrant expression of the 'leukocyte' integrin LFA-1 on epithelial cells in chronic autoimmune thyroiditis. In the present study we investigated whether conjunctival epithelial cells, which bear the adhesion molecule ICAM-1 on their surface during allergic inflammation, may also aberrantly express its natural ligand, the 'leukocyte' integrin LFA-1., Methods: We studied 13 patients with rhinoconjunctivitis allergic to mites, chronically exposed to the allergen, 11 patients allergic to pollen tested out of the pollen season and 8 normal volunteers. Single and double immunocytochemical staining of conjunctival smears was employed., Results: LFA-1 staining on epithelial cells was demonstrated in 12/13 patients allergic to mites and not in normal controls or in patients allergic to pollen tested out of the pollen season. The epithelial localization of LFA-1 was confirmed by double staining with anti-LFA-1 and anti-cytokeratin antibodies (both immunocytochemical and immunofluorescence)., Conclusions: Coexpression of LFA-1 and ICAM-1 during persistent allergen stimulation may be relevant for interaction between epithelial cells and activated effector cells, such as eosinophils, which bear on their surface both ICAM-1 and its beta2 integrin ligands., (Copyright 2001 S. Karger AG, Basel)

We have evaluated the expression of different molecular forms of T cell antigen receptor (TcR) in duodenal biopsies of pediatric patients with different forms of villous atrophy: celiac disease, autoimmune enteropathy, intractable diarrhea of unknown origin, and severe cow milk intolerance. A panel of monoclonal antibodies recognizing alpha/beta and gamma/delta TcR (and gamma/delta TcR subsets) was used for immunostaining. The results showed an increase of T cells with gamma/delta-type TcR in celiac patients and also in patients with other forms of villous atrophy with respect to normal controls. Amongst the gamma/delta TcR-positive cells, the subset expressing the molecular product of V delta 1 region was the most represented. The gamma/delta TcR-positive T cells were mainly located within the epithelium: few of them were observed in the lamina propria. On the basis of these results, we hypothesize that the increased homing of gamma/delta TcR-positive T lymphocytes in gut epithelium observed in celiac disease is, at least in part, related to villous atrophy per se.