The impact of gastric Helicobacter pylori infection on duodenal mucosa: New evidence on the alteration of intraepithelial lymphocytes.

Objective: This study aimed to elucidate the effect of gastric Helicobacter pylori (HP) colonization on the duodenal mucosa, focusing on intraepithelial lymphocyte (IEL) numbers and localizations.

Methods: The paired gastric and duodenal tissues from 132 patients with celiac disease (CD) and 190 individuals without CD were examined. Gastric HP status (presence and intensity) was compared with IEL counts per 100 enterocytes (IEL/100), localizations (basal-apical), and endoscopic, serologic, and clinicopathologic parameters.

Results: H pylori was detected in 176 (54.7%) gastric tissues, and its presence did not significantly change the duodenal IEL/100 counts in either CD (P = .121) or non-CD (P = .400) cases. It was seen in older individuals (P = .003), and age was also associated with HP intensity (P = .027). In non-CD cases, duodenal intraepithelial lymphocytosis (DIL) in HP-positive and HP-negative samples was 37 (33.9%) and 31 (38.3%), respectively (P = .538). Although a slight increase was observed with sparse HP colonization (+), intense colonization (+++) was significantly associated with less scalloping (P = .037), lower IEL/100 (P = .003), and antiendomysial antibody IgA (P = .048). A similar pattern was also observed in tissue transglutaminase IgA titers (P = .053).

Conclusions: Considering the effect of gastric HP on duodenal IELs, endoscopic and serologic parameters, depending on its intensity, will provide a more accurate estimation in cases where the cause of DIL is investigated.