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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Antigens, Differentiation, T-Lymphocyte, Antigens, Neoplasm, CD4-Positive T-Lymphocytes, Cells, Cultured, Cholecalciferol, Dermatitis, Contact, Down-Regulation, E-Selectin, Humans, Male, Membrane Glycoproteins, Mice, Mice, Inbred C57BL, Receptors, Lymphocyte Homing, Skin, T-Lymphocytes, Vitamin A.
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Are vitamins A and D potent inhibitors of cutaneous lymphocyte-associated antigen expression? Context: Cutaneous lymphocyte-associated antigen (CLA) is a surface glycoprotein expressed by skin-homing T cells. This carbohydrate moiety expressed on mucin-like surface glycoproteins, including P-selectin glycoprotein ligand 1 and CD43, confers binding activity to dermal endothelial E-selectin and is critical for T-cell recruitment to the skin. Vitamin A (retinoic acid [RA]) and the active form of vitamin D3 (1,25 dihydroxyvitamin D3 [1,25D(3)]) have been used to treat certain T cell-mediated inflammatory skin diseases, as well as cutaneous T-cell lymphomas; however, their effect on CLA expression has not been studied. We analyzed the effects of RA and 1,25D(3) on expression of CLA and other lymphocyte-homing receptors on human T cells. We cultured human T cells with 1,25D(3) and RA and analyzed the expression of CLA and other homing receptors. We also pretreated mice with either vitamin and then induced an antigen-dependent contact hypersensitivity response. Both RA and 1,25D(3) downregulated expression of the CLA and, in parallel, functional E-selectin ligand. Whereas RA increased expression of the gut-homing receptor alpha4beta7 and reduced L-selectin expression, 1,25D(3) had no effect on other homing receptors. In an in vivo assay treatment with RA or 1,25D(3) downregulated the skin infiltration of effector CD4+ T cells.
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These findings suggest that 1,25D(3) can selectively downregulate CLA expression without influencing lymphocyte migration patterns to other tissues. Final Decision: yes