INTERLEUKIN-3, GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR, AND INTERLEUKIN-5 IN EOSINOPHILIC GASTROENTERITIS

Background & Aims: Eosinophilic gastroenteritis (EG) is characterized by an eosinophilic infiltration of the gastrointestinal tract. The mec hanism for the intestinal recruitment of eosinophils in EG remains unk nown. Eosinophil recruitment and activation is induced by three main c ytokines: interleukin (IL) 3, granulocyte-macrophage colony-stimulatin g factor (GM-CSF), and IL-5. The aim of this study was to examine the immunoreactivity for IL-3, GM-CSF, and IL-5 within the duodenal and co lonic mucosa of 10 patients with EG. Methods: Endoscopic biopsy specim ens were obtained from 10 patients with 50 and 10 controls. IL-3, GM-C SF, and IL-5 was evaluated by immunohistochemistry. Electron microscop y combined with immunogold staining was used to identify the labeled c ells and to localize these growth factors ultrastructurally. Results: A significant increase in the number of eosinophils was found in both duodenal and colonic mucosa from all 10 patients with EG compared with controls. In the same tissue, immunohistochemistry detected IL-3, GM- CSF, and IL-5 in 9 of 10 patients with EG. The one exception had recei ved treatment with steroids. These cytokines were not detected in the control group. Ultrastructurally, IL-3, GM-CSF, and IL-5 were localize d in the granule matrix of eosinophils. Conclusions: The release of th ese cytokines with autocrine and/or paracrine activities by eosinophil s may be involved in the persistence of intestinal eosinophil infiltra tion.