Expression of mRNA for interferon-gamma, interleukin-10, and interleukin-12 (p40) in normal gastric mucosa and in mucosa infected with Helicobacter pylori

Background: We studied the mRNA expressions of interferon-gamma (IFN-gamma), interleukin-10 (IL-10), and IL-12 in gastric biopsy and blood samples from patients with and without Helicobacter pylori infection, by reverse-transcription polymerase chain reaction (RT-PCR). Methods: RT-PCR was performed on total RNA preparations, and the expressed mRNA were semiquantitated on the basis of band intensities on Southern blots. Results: In gastric mucosa the expression of IFN-gamma and IL-10 was found in most patients with and without H. pylori infection, whereas IL-12 was found in most of the infected ones. The level of IFN-gamma and IL-10 did not differ between groups, whereas the IL-12 level was significantly higher in those with H. pylori infection. In the blood IFN-gamma expression was found in most samples, with higher level in patients with gastritis than in normals. Few blood samples (33%) had IL-12, and none had IL-10. Conclusion: IFN-gamma and IL-10 expressions in healthy mucosa may indicate a biologic role in a healthy state. IL-12 expression in mucosa was related to the presence of bacterial stimulant and therefore resembles proinflammatory cytokines.