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/or IgG antibodies to gliadin (AGA). The aim of the present study was to evaluate 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 antibodies 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. Thirty of the 33 patients with AGA completed the GFD period, after which they showed a highly significant decrease in mean PASI. This included a significant decrease in the 16 AGA-positive patients with normal routine histology 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 patients with elevated AGA. When the ordinary diet was resumed, the psoriasis 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 intraepithelial lymphocytes is slight or seemingly absent.

Patients with psoriasis often have increased serum levels of IgA antibodies to gliadin.

It was recently observed that in six patients with psoriasis and one with palmoplantar pustulosis, with newly discovered gluten intolerance, a gluten-free diet had a remarkable effect on the skin lesions. This prompted us to undertake a screening investigation to discover whether increased levels of serum antibodies to gliadin are more common in patients with psoriasis than in healthy persons. IgA and IgG antibodies to gliadin (IgA AGA and IgG AGA) were quantified by a micro-ELISA method. Out of 302 patients with psoriasis, 16% (18 females, 31 males) showed serum IgA AGA levels above the 90th percentile value (51 u/ml) of the reference group. This tendency was even more marked when the proportion of patients with values > 70 u/ml was compared with the corresponding proportion of 99 reference subjects. Thus, 3% of the reference subjects but 7.9% of the patients had values > 70 u/ml. The corresponding figures for men were 1.6% and 8.9%, respectively. Men with psoriasis had a significantly higher mean IgA AGA than the male reference group. The means based on logarithmic values of the individual IgA AGA values were significantly higher in the psoriatic groups than in the reference groups. Although the mean level of IgG AGA was not increased in the psoriasis group, there was a correlation between the values for IgA AGA and IgG AGA. The serum concentrations of IgG, IgA and IgM were also measured. In the male patients, the mean IgA value was significantly increased. Women in whom IgA AGA was elevated also showed a significantly increased mean IgA.(ABSTRACT TRUNCATED AT 250 WORDS)