Objectives:The aim was to investigate the expression of cytokines, adhesion molecules, and activation and proliferation markers in duodenal biopsies from children with delayed‐type food allergy (FA).Methods:Seven children with untreated FA (uFA), seven children with treated FA (tFA) to cow milk and/or cereals, and five normal controls furnished duodenal biopsy specimens. Additionally, five pediatric patients with celiac disease were included, serving exclusively as positive controls forin situhybridization. Interferon‐&ggr; (IFN‐&ggr;), interleukin‐4 (IL‐4), adhesion molecules, and activation markers were detected by immunohistochemistry, and expression of IFN‐&ggr; and IL‐4 messenger RNA was revealed byin situhybridization.Results:uFA patients had a higher density of IFN‐&ggr; positive cells in the lamina propria than did tFA patients and controls (P= 0.053 andP= 0.018). Moreover, the uFA patients exhibited a higher proportion of crypt cells in mitosis than did tFA patients (P= 0.026), and stronger staining of HLA‐DR in the crypts and increased density of &ggr;&dgr;‐T cell receptor‐positive intraepithelial lymphocytes than did controls (P= 0.048 andP= 0.010). The densities of &agr;4&bgr;7positive cells in the lamina propria tended to be higher in controls than in uFA or tFA patients (P= 0.106,P= 0.073). Expression of IL‐4 mRNA was significantly higher in celiac patients than in the other study groups (uFAP= 0.006, tFAP= 0.010; controlsP= 0.029), and celiac patients showed higher expression of IFN‐&ggr; mRNA than did tFA patients or controls (P= 0.017 andP= 0.016).Conclusions:As expected, Th1 dominance was present in the lamina propria of children with delayed‐type FA. It may cause activation of epithelial cells and increase their turnover.