Psoriasis patients with antibodies to gliadin can be improved by a gluten-free diet

In a previous screening study, 16% of patients with psoriasis had IgA and/o r IgG antibodies to gliadin (AGA). The aim of the present study was to eval uate the effect of a gluten-free diet (GFD) in 33 AGA-positive and six AGA- negative psoriasis patients. Of the 33 AGA-positive patients, two had IgA a ntibodies to endomysium (EmA) and 15 an increased number of lymphocytes in the duodenal epithelium, but in some this increase was slight, Two patients had villous atrophy. A 3-month period on a GFD was followed by 3 months on the patient's ordinary diet. The severity of psoriasis was evaluated with the psoriasis area and severity index (PASI), The examining dermatologists were unaware of the EmA and duodenal biopsy results throughout the study, T hirty of the 33 patients with AGA completed the GFD period, after which the y showed a highly significant decrease in mean PASI, This included a signif icant decrease in the 16 AGA-positive patients with normal routine histolog y in duodenal biopsy specimens. The AGA-negative patients were not improved , After GFD, the AGA values were lower in 82% of those who improved. There was a highly significant decrease in serum eosinophil cationic protein in p atients with elevated AGA. When the ordinary diet was resumed, the psoriasi s deteriorated in 18 of the 30 patients with AGA who had completed the GFD period. In conclusion, psoriasis patients with raised AGA might. improve on a GFD even if they have no EmA or if the increase in duodenal intraepithel ial lymphocytes is slight or seemingly absent.