Mucosal interleukin-21 mRNA expression level is high in patients with Helicobacter pylori and is associated with the severity of gastritis

Helicobacter pylori (H. pylori) infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells. Different clinical forms of the infection may reflect distinctive patterns of cytokine expression. Interleukin (IL)-17, IL-21, IL-22, and IL-23 have been reported to be involved in H. pylori-induced gastric mucosal inflammation, but the details and relationship to different patterns of inflammation and virulence factors remain unclear. The present study was launched to analyse IL-6 expression in H. pylori-infected and uninfected gastric patients and to investigate its correlation with chronic gastritis among H. pylori-infected patients. Total RNA was extracted from the gastric antrum biopsies of 48 H. pylori-infected patients and 38 H. pylori uninfected patients. Mucosal IL-21 mRNA expression level in H. pylori-infected and uninfected gastric biopsy was determined by real-time PCR. The presence of vacA (vacuolating cytotoxin A) and cagA (cytotoxin associated gene A) virulence factors were evaluated using PCR. Interleukin-21 mRNA expression was significantly high in biopsies of H. pylori-infected patients compared to H. pylori uninfected patients, and the mucosal IL-21 mRNA level was positively correlated with the grade of chronic inflammation. There was no association between virulence factors and IL-21 mRNA expression. We believe that IL-21 might be involved in the pathogenesis of H. pylori and might be an index of the severity of chronic gastritis.