Twenty one children with dermatitis herpetiformis were studied in an attempt to 
evaluate the response in the skin, in jejunal morphology, and in jejunal 
immunoglobulin containing cell counts to gluten elimination and subsequent 
gluten challenge. In all of the 15 patients whose jejunal biopsy was studied 
after the eventual gluten challenge the jejunal lesion had returned in 2.4 to 28 
months. The numbers of IgA- and IgM-containing cells were similarly raised in 
primary and postchallenge biopsies. In the 13 patients whose skin improved 
during a gluten free diet and who were challenged with gluten the rash worsened 
and the dapsone/sulphapyridine requirement increased. The jejunal deterioration 
was equally marked in the six patients whose gluten challenge was stopped 
because of an intractable rash as it was in those who completed the preplanned 
challenge. The specimens of the former, however, had significantly more 
IgA-containing cells than specimens of the latter. The number of intraepithelial 
lymphocytes clearly reflected the degree of intestinal damage. IgA-containing 
cells proved to be the most sensitive indicator of an immune reaction taking 
place in the gut of these patients. Even in the two children with initially 
normal or nearly normal jejunal mucosa, the IgA cell counts in the jejunal 
lamina propria were markedly raised.