[CD4+ and CD8+ T cells in gastric mucosa in children infected with Helicobacter pylori].

OBJECTIVE

To study the changes of gastric mucosal CD4(+) and CD8(+) T cells in Helicobacter pylori (Hp) infected children.

METHODS

Seventy nine patients with digestive tract symptoms were assessed by endoscopy, rapid urease test and histology. Forty four patients had Hp positive chronic superficial gastritis (Hp(+)CSG) and 35 patients had Hp negative chronic superficial gastritis (Hp(-)CSG). Gastric biopsy specimens were obtained from each patient. Peripheral blood samples were obtained from 33 patients (12 with Hp(+)CSG, 21 with Hp(-)CSG). Hp infection was identified by rapid urease test and histology. Hp infection was confirmed when a patient was positive for both of these tests. Four pieces of gastric antrum mucosal specimens were placed in Hank's balanced salt solution containing 1 mmol/L dithiothreitol (DTT) and 1 mmol/L ethylenediamine tetraacetic acid (EDTA). The specimens were treated with collagenase type I (120 U/ml) for three hours at 37 degrees C with agitation. The mononuclear cells were collected by removing undigested material and washed three times with RPMI 1640. Isolated gastic mononuclear cells were stained with CD3-FITC (fluorescein isothiocyanate), CD4-PE (R-phycoerthrin), CD8-PerCP (Peridinin-chlorophyll-alpha-protein) and measured by flow cytometry. Mucosal T lymphocytes were gated for the expression of CD3. Peripheral blood lymphocyte subsets were analysed by direct immunofluorescence.

RESULTS

The percentage of isolated gastric mononuclear cells within the CD3 gate were 3.26 +/- 1.98 in Hp(-)CSG, 4.37 +/- 1.97 in Hp(+)CSG. Relative CD4(+)(%), CD8(+)(%) and CD4(+)/CD8(+) of the CD3(+) cells respectively were 23.74 +/- 10.37, 47.04 +/- 12.00, 0.52 +/- 0.23 in Hp(-)CSG group, 40.28 +/- 11.35, 27.91 +/- 8.84, 1.55 +/- 0.52 in Hp(+)CSG group. CD4(+)(%), CD4(+)/CD8(+) in Hp(+)CSG group were significantly higher than those of Hp(-)CSG group and CD8(+)(%) was lower than those of Hp(-)CSG group (P < 0.01). There were no significant differences in peripheral blood T lymphocyte subsets between the two groups.

CONCLUSION

The difference of gastric T lymphocyte response between Hp(+)CSG and Hp(-)CSG in children indicated that the local cellular immune reaction may play a critical role in the pathogenesis of Hp infection.