Helicobacter pylori modulation of gastric and duodenal mucosal T cell cytokine secretions in children compared with adults.
BACKGROUND
In contrast to adults, ulcers are un-common in Helicobacter pylori-infected children. Since immunological determinants influence the outcome of H. pylori infection, we have investigated mucosal T cell responses in H. pylori-infected children and compared them with those of adults and negative controls.


METHODS
Mucosal biopsies were obtained from 43 patients undergoing an upper GI endoscopy for dyspeptic symptoms. The concentrations of released cytokines and the density of CD3+, CD25+ and CD69+cells were evaluated by flow cytometry, and the numbers of cytokine-secreting cells were measured by ELISPOT.


RESULTS
The numbers of isolated antral CD3+ lymphocytes were only significantly raised in infected adults compared with noninfected controls (p < 0.05), whereas the proportion of CD3+ cells expressing activation markers (CD25 or CD69) remained low. In the stomach, IFN-gamma concentrations increased in infected children and infected adults compared with controls (p < 0.05), but IFN-gamma concentrations were tenfold lower in children than in adults (p < 0.01). IL-2, IL-4, IL-10 and TNF-alpha concentrations were similar in infected and in uninfected children and adults. In contrast, in the duodenum, IFN-gamma, as well as IL-4 and IL-10 concentrations were only increased in infected children compared with controls (p < 0.05). The concentrations of these cytokines were similar in both groups of adults who, however, like children, displayed a higher number of duodenal IL-4-secreting cells compared to controls (p < 0.05).


CONCLUSIONS
These results suggest that IFN-gamma secretion in the stomach of H. pylori-infected patients is lower in children than in adults. This could protect children from development of severe gastro-duodenal diseases such as ulcer disease. In addition, infected patients are characterised by a dysregulation of the mucosal cytokine secretion at distance from the infection site.
Bontems
Patrick
P
Department of Immunology and Gastroenterology - Erasme Hospital, Brussels, Belgium.
Robert
Fabienne
F
Van Gossum
André
A
Cadranel
Samy
S
Mascart
Françoise
F
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D004386:Duodenum / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology* / Q000378:metabolism; D016480:Helicobacter pylori; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism*; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011706:Pyloric Antrum / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D013601:T-Lymphocytes / Q000378:metabolism / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma