Gluten-free diet in dermatitis herpetiformis. II. Morphological and immunological findings in the skin and small intestine of 12 patients and matched controls.

Twelve patients with dermatitis herpetiformis whose skin condition responded to a gluten-free diet (GFD) were re-examined after diet treatment. The findings were compared with those in matched patients on a normal diet. Jejunal histology revealed morphological improvement in every patient on a GFD whereas all patients on a normal diet continued to have villous atrophy. Intra-epithelial lymphocyte counts were normal in 8 patients on a GFD in contrast to one on a normal diet. Immunofluorescence examination of the jejunal mucosa revealed that the numbers of cells containing IgA and IgM were increased significantly in the normal diet group. The figures were lower in the GFD group but these also exceeded the values in the controls. IgA deposits were found in the uninvolved skin of every patient irrespective of the diet treatment, but the fluorescence seemed to be less intense in patients on a GFD. A clear difference was found in the occurrence of C3 deposits in the uninvolved skin. Three patients on a GFD had C3 deposits; two of these did not follow a strict diet. However C3 was found in 8 patients on a normal diet. Circulating dietary and auto-antibodies were found in two patients on a GFD and in 9 on a normal diet. Serum immunoglobulin (IgG, IgA, IgM) and complement (C3, C4) levels were within normal limits in both patient groups.