The role of IFN-gamma and IL-4 in gastric mucosa inflammation associated with Helicobacter heilmannii type 1 infection.

Although Helicobacter heilmannii infection is less common than H. pylori infection in humans, it is considered to be of medical importance because of its association with gastritis, gastric ulcer, carcinoma, and mucosa-associated lymphoid tissue lymphoma of the stomach. However, there have been no studies evaluating the role of the Th cell response in H. heilmannii gastric infection. We evaluated the participation of pro-inflammatory and anti-inflammatory cytokines, IFN-gamma and IL-4, in H. heilmannii gastric infection in genetically IFN-gamma- or IL-4-deficient mice. The serum IFN-gamma and IL-4 concentrations were determined by ELISA. The gastric polymorphonuclear infiltrate was higher (P = 0.007) in H. heilmannii-positive than in H. heilmannii-negative wild-type (WT) C57BL/6 mice, whereas no significant inflammation was demonstrable in the stomach of H. heilmannii-positive IFN-gamma(-/-) C57BL/6 mice. The degree of gastric inflammatory cells, especially in oxyntic mucosa, was also higher (P = 0.007) in infected IL-4(-/-) than in WT BALB/c mice. Serum IFN-gamma levels were significantly higher in IL-4(-/-) than in WT BALB/c mice, independently of H. heilmannii-positive or -negative status. Although no difference in serum IFN-gamma levels was seen between H. heilmannii-positive (11.3 +/- 3.07 pg/mL, mean +/- SD) and -negative (11.07 +/- 3.5 pg/mL) WT BALB/c mice, in the group of IL-4(-/-) animals, the serum concentration of IFN-gamma was significantly higher in the infected ones (38.16 +/- 10.5 pg/mL, P = 0.04). In contrast, serum IL-4 levels were significantly decreased in H. heilmannii-positive (N = 10) WT BALB/c animals compared to the negative (N = 10) animals. In conclusion, H. heilmannii infection induces a predominantly Th1 immune response, with IFN-gamma playing a central role in gastric inflammation.

The role of IFN-gamma and IL-4 in gastric mucosa inflammation associated with Helicobacter heilmannii type 1 infection

Although Helicobacter heilmannii infection is less common than H. pylori infection in humans, it is considered to be of medical importance because of its association with gastritis, gastric ulcer, carcinoma, and mucosa-associated lymphoid tissue lymphoma of the stomach. However, there have been no studies evaluating the role of the Th cell response in H. heilmannii gastric infection. We evaluated the participation of pro-inflammatory and anti-inflammatory cytokines, IFN-gamma and IL-4, in H. heilmannii gastric infection in genetically IFN-gamma- or IL-4-deficient mice. The serum IFN-gamma and IL-4 concentrations were determined by ELISA. The gastric polymorphonuclear infiltrate was higher (P = 0.007) in H. heilmannii-positive than in H. heilmannii-negative wild-type (WT) C57BL/6 mice, whereas no significant inflammation was demonstrable in the stomach of H. heilmannii-positive IFN-gamma-/- C57BL/6 mice. The degree of gastric inflammatory cells, especially in oxyntic mucosa, was also higher (P = 0.007) in infected IL-4-/- than in WT BALB/c mice. Serum IFN-gamma levels were significantly higher in IL-4-/- than in WT BALB/c mice, independently of H. heilmannii-positive or -negative status. Although no difference in serum IFN-gamma levels was seen between H. heilmannii-positive (11.3 ± 3.07 pg/mL, mean ± SD) and -negative (11.07 ± 3.5 pg/mL) WT BALB/c mice, in the group of IL-4-/- animals, the serum concentration of IFN-g was significantly higher in the infected ones (38.16 ± 10.5 pg/mL, P = 0.04). In contrast, serum IL-4 levels were significantly decreased in H. heilmannii-positive (N = 10) WT BALB/c animals compared to the negative (N = 10) animals. In conclusion, H. heilmannii infection induces a predominantly Th1 immune response, with IFN-gamma playing a central role in gastric inflammation.

Phenotypic study of peripheral blood lymphocytes and humoral immune response in Helicobacter pylori infection according to age.

There are differences between children and adults in certain aspects of the Helicobacter pylori (HP) infection, among them the lower titre of IgG antibodies anti-HP in the former group. Thus, we investigated by means of flow cytometry CD4+/CD3+ (CD4+T), CD8+/CD3+ (CD8+T) and CD19+/CD3- (B) cells, activation/co-stimulatory markers (CD4+/HLA-DR+, CD4+/CD28+, CD8+/HLA-DR+ and CD8+/CD28+) and by means of ELISA IgG anti-HP antibodies in the peripheral blood from HP-positive and -negative children and adults. An increased CD4+/CD28+ and CD8+/CD28+ percentage and number of CD4+/CD3+ cells were seen in infected adults. Conversely, no difference was observed between infected and noninfected children, but when they were stratified by age, an increased CD4+/CD28+ cell percentage was seen in the HP-positive group older than 10 years. The mean level of IgG anti-HP was lower in younger infected children, increased with age and correlated with CD4+ cells. Our data suggest that the immune response to HP infection vary according to the age. Low percentage of activated CD4+ cell may contribute to the lower level of serum IgG anti-HP observed in younger infected children. In addition, the CD4+ cell participation during the infection seems to begin after 10 years old, when the immune response becomes similar to that seen in adults.

Prevalence and risk factors associated with Helicobacter pylori infection in native populations from Brazilian Western Amazon.

We evaluated the prevalence of, and factors associated with, Helicobacter pylori infection in 222 subjects from 3 distinct communities of native populations (Uru-Eu-Wau-Wau Indians and 2 riverine communities living on the banks of the Machado river and in Portuchuelo) living in isolation in the rainforest of Brazilian Western Amazon. The overall prevalence was 78.8% (95% CI 72.7-83.9). The prevalence was higher in the Machado river community compared with Portuchuelo (chi2 = 3.84, P = 0.05), but no significant difference was observed between the Machado river community and the Uru-Eu-Wau-Wau Indians. Logistic regression showed that residential crowding and age were factors associated with the presence of H. pylori infection. Acquisition of the bacterium started early in life and by the age of 2 years 50% of children were infected. The prevalence increased with age, reaching near universal levels during adulthood (97.9%). Residential crowding was high with a global index of 3.3 persons/room (SD = 1.8), varying significantly between the 3 communities (P = 0.001). These data provide further evidence supporting direct person-to-person spread of the bacterium.