IgG4+ cells are increased in the gastrointestinal tissue of pediatric patients with active eosinophilic gastritis and duodenitis and decrease in remission.

ABSTRACT

BACKGROUND: Recent studies have shown that IgG4 is increased in the esophageal tissue of eosinophilic esophagitis patients, including the presence of IgG4+ plasma cells. AIMS: Our aim was to determine whether IgG4 is elevated in the gastric or duodenal tissue of pediatric patients with eosinophilic gastritis or duodenitis (EoG or EoD). METHODS: This was a retrospective single center study. Pediatric patients were characterized as having active EoG, EoD, or as controls based on clinical symptoms and histologic features. Immunohistochemistry for IgG4 was performed in gastric and duodenal tissue, and peak IgG4+ cells were compared between groups and after treatment. RESULTS: The frequency of IgG4+ cells was significantly higher in patients with EoG and EoD compared to controls in the stomach [EoG 6.5 cells/hpf (3.6-10.9), control 0 cells/hpf (0-0.7), p<0.0001] and duodenum [EoD 7.5 cells/hpf (2.8-37), control 0.5 cells/hpf (0.3-1.3), p<0.001)] respectively, and positively correlated with eosinophil counts (stomach r 0.74, p<0.0001; duodenum r 0.57, p<0.0001). The amount of tissue IgG4 was significantly decreased in patients in remission but not in persistently active disease. CONCLUSIONS: These data suggest local tissue production of IgG4 may be a universal feature of eosinophilic gastrointestinal disease that tracks with disease activity.