Deposition of eosinophil granule major basic protein in eosinophilic gastroenteritis and celiac disease.

Degrees of eosinophil infiltration and eosinophil degranulation, as evidenced by localization of the eosinophil granule major basic protein (MBP), were compared in patients with eosinophilic gastroenteritis, patients with celiac disease, and healthy controls using a specific indirect immunofluorescence technique for the localization of MBP. Formalin-fixed, paraffin-embedded biopsy specimens from the mucosa of the stomach and small intestine of 11 patients with eosinophilic gastroenteritis, from the small intestine of 4 patients with celiac disease, and from the stomach and/or upper small intestine of 18 healthy asymptomatic volunteers were tested. Degrees of eosinophil infiltration and extracellular deposition of MBP were graded by two blinded observers; each section was given a score from 0 (nil) to 4 (marked). In the small bowel biopsy specimens, both eosinophil infiltration and extracellular MBP deposition scores were significantly greater in patients with eosinophilic gastroenteritis and in patients with celiac disease than in controls. In the gastric biopsy specimens, extracellular MBP deposition scores were significantly increased in patients with eosinophilic gastroenteritis compared with controls even though eosinophil infiltration scores did not differ significantly at this site. The results support the hypothesis that the eosinophil, through toxic cationic proteins such as MBP, plays a role in the pathogenesis of these diseases.