Although possessing a morphologically similarsmall bowel abnormality to patients with isolatedgluten-sensitive enteropathy (GSE), patients withdermatitis herpetiformis (DH) have few gastrointestinal symptoms and exhibit blistering skin lesionsand cutaneous IgA deposits. To determine whetherclinical discrepancies between these gluten-sensitiveconditions might be the result of different patterns of small bowel cytokine expression, duodenalbiopsies were obtained from eight DH patients and nineisolated GSE patients. Biopsies were evaluated forinterleukin-4 (IL-4) and interferon-γ(IFN-γ) expression by reverse-transcriptase polymerasechain reaction (message) and immunohistochemistry(protein). In DH patients, most of whom had no gutsymptoms, IFN-γ mRNA expression was significantly less than in isolated GSE patients withsymptomatic gut disease. Conversely, IL-4 mRNAexpression in DH patients was greater than that foundamong isolated GSE patients. These findings suggest thatthe different clinical phenotypes of glutensensitivity may be caused by variation in cytokineexpression in the small bowel response togluten.