Gluten-free Diet in Psoriasis Patients with Antibodies to Gliadin Results in Decreased Expression of Tissue Transglutaminase and Fewer Ki67+ Cells in the Dermis
Previous studies have shown that 16% of patients with psoriasis vulgaris have IgA and/or IgG antibodies to gliadin, but few have antibodies to endomysium. The increase in duodenal intraepithelial lymphocytes was mild. Still, highly significant clinical improvement was observed after 3 months on a gluten-free diet. This study surveys certain immunohistological aspects of involved and non-involved skin in 28 AGA-positive psoriasis patients before and after 3 months of a gluten-free diet. Staining was performed for CD4+ T lymphocytes, Langerhans' cells, endothelium, proliferating (Ki67) cells and tissue transglutaminase. In the entire group of patients, as well as in those on a gluten-free diet as the only treatment, Ki67+ cells in involved dermis were highly significantly decreased after the diet. There was a significant decrease in Ki67+ cells even in patients without increased intraepithelial lymphocytes. Tissue transglutaminase was highly overexpressed in involved skin in the papillary endothelium, and decreased by 50% after gluten-free diet. The possible role of tissue transglutaminase in the pathogenesis of psoriasis needs further investigation.