Inflammatory cell numbers in the stomach of Japanese subjects with endoscopically normal mucosa without H. pylori infection.

INTRODUCTION Since inflammatory cells, such as lymphocytes and plasma cells, normally inhabit the stomach, the border between normal and mild inflammation is difficult to visually determine using the updated Sydney system scale of gastritis. Additionally, eosinophils in the gastric mucosa must be counted to diagnose eosinophilic gastritis. We aimed to determine the normal number of inflammatory cells in patients with endoscopically normal mucosa and without H. pylori infections. METHODS We assessed patients aged 20-79 years, who had undergone upper gastrointestinal endoscopy at Kawasaki Medical School Hospital between January 2010 and December 2014. Inflammatory cells were counted in 1,000 μm2 fields of pyloric and fundic gland mucosal biopsy specimens. We finally included 325 (male, n = 141; female, n = 184; average age = 49.3 years) patients without inflammation who had H. pylori-negative endoscopic results and negative histological findings interpreted based on the updated Sydney System and the Kyoto classification of gastritis. RESULTS The average numbers of nucleated cells were 83.3 ± 14.2/mm2 and 65.4 ± 12.6/mm2 in the pyloric and fundic gland mucosae, respectively. Inflammatory cells were significantly more abundant in the pyloric mucosa than the fundic gland mucosa (p < 0.05). Age and sex distribution did not significantly differ. Eosinophils were absent or scanty in the gastric mucosae of both glands in all patients. CONCLUSION We determined the absolute values of inflammatory cells, including eosinophils, in normal mucosae of pyloric and fundic glands. These findings could be important in defining gastric mucosal inflammation, including eosinophilic gastritis diagnosis.