Increased interleukin-10 in Helicobacter pylori infection could be involved in the mechanism protecting from allergy.
BACKGROUND
A protective effect of Helicobacter pylori infection against allergic diseases has been reported. The increasing incidence of childhood allergy in developed countries may be a result of reduced stimulation of the immune system by early chronic infections, with the protective effect of gastrointestinal microbes being mediated by regulatory T lymphocytes and production of interleukin (IL)-10. To elucidate a possible mechanism involved in protecting against the development of atopy, we measured expression of IL-10 in gastric mucosa of children with H pylori gastritis.


METHODS
Gastric biopsies were performed during endoscopy in 48 children (median age, 9 years), 32 of whom had H pylori gastritis and 16 of whom served as controls. Interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), and IL-10 were measured in tissue homogenate by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The amounts of IFN-gamma, IL-1beta, and IL-10 transcripts were quantified via competitive RT-PCR with use of dilution series of specific competitors.


RESULTS
Expression of IFN-gamma and IL-10 were significantly higher in H pylori-infected children. No direct correlation with age was found, but a further increase in IL-10 expression was found in H pylori-infected children older than 4 years, whereas in control subjects, IL-10 expression tended to be lower in older children. IL-1beta expression was similar in infected children and control subjects. In H pylori-infected children, the prevalence of allergy was significantly higher in children with lower cytokine expression in gastric mucosa.


CONCLUSIONS
In children, H pylori-induced inflammatory response is associated with development of cell-mediated immunity of T-helper 1 type, as demonstrated by increased IFN-gamma expression. The significantly increased expression of gastric IL-10 in H pylori-infected children and its further increase in older children suggest that this chronic infection may influence IL-10 production even beyond the age of 4 years. H pylori may be one of the infections with the potential to modulate immune responses.
Oderda
Giuseppina
G
Department of Pediatrics, Clinica Pediatrica,Università del Piemonte Orientale, Novara, Italy. oderda@med.unipmn.it
Vivenza
Daniela
D
Rapa
Anna
A
Boldorini
Renzo
R
Bonsignori
Ilaria
I
Bona
Gianni
G
D000293:Adolescent; D000367:Age Factors; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D005756:Gastritis / Q000276:immunology* / Q000382:microbiology; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000517:prevention & control*; D007111:Immunity, Cellular; D007223:Infant; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis*; D053583:Interleukin-1beta / Q000096:biosynthesis; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction
D053583:Interleukin-1beta; D016753:Interleukin-10; D007371:Interferon-gamma