Pediatric Helicobacter pylori infection and circulating T-lymphocyte activation and differentiation.
BACKGROUND
In this study, H. pylori-infected and noninfected children with gastritis were compared to a control group with respect to circulating CD4(+) and CD8(+) T lymphocytes expressing activation and differentiation markers. Additionally, the lymphocyte phenotypes of children with gastritis were correlated with the gastric inflammation scores.


METHODS
H. pylori infection status was assessed based on [¹³C]urea breath test, rapid urease test, and histology. Analysis of the lymphocyte surface molecule expression was carried out by triple-color flow cytometry.


RESULTS
The group of H. pylori-infected children showed an elevated proportion of peripheral B cells with CD19(low) , along with a twofold increase in the percentage of memory (CD45RO(+)) CD4(+) and CD8(+) T-cell subsets (p < .05). Moreover, a positive correlation between the age and the percentage of these subsets was seen (r = .38, p = .04 and r = .56, p < .01, respectively). Children with gastritis but without infection had a slightly increased percentage of CD8(+) T cells and CD56(+) NK cells, CD3(high) T cells and CD45RO(high) CD4(+) T-cell subsets (p < .05). Both H. pylori-infected and noninfected children with gastritis were characterized by an increased percentage of memory/effector CD4(+) T cells, the presence of NK cells with CD56(high), memory T-cell subset with CD4(high), and naive, memory, memory/effector, and effector T-cell subsets with CD8(high) (p < .05). Gastric inflammation scores correlated positively with the percentage of CD4(+) T lymphocytes in H. pylori-infected children (r = .42, p = .03). In noninfected children, gastric inflammation scores correlated positively with the percentage of B cells (r = .45, p = .04).


CONCLUSIONS
In H. pylori-negative children, gastritis was associated with an increased percentage of activated NK and T cells, and intermediate-differentiated peripheral blood CD4(+) T cells, which was more pronounced in H. pylori-positive children who also showed an increased B-cell response. However, increased inflammation was only associated with the elevation of CD4(+) T-cell percentage in H. pylori-positive children as well as B-cell percentage in H. pylori-negative children with gastritis.
Department of Immunology, Collegium Medicum Nicolaus Copernicus University, Bydgoszcz, Poland. a.helminbasa@gmail.com
Anna
A
Helmin-Basa
Jacek
J
Michalkiewicz
Lidia
L
Gackowska
Izabela
I
Kubiszewska
Andrzej
A
Eljaszewicz
Grazyna
G
Mierzwa
Grazyna
G
Bala
Mieczyslawa
M
Czerwionka-Szaflarska
Andrzej
A
Prokurat
Andrzej
A
Marszalek
D000293:Adolescent; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D001944:Breath Tests; D002648:Child; D005260:Female; D005434:Flow Cytometry; D005756:Gastritis / Q000276:immunology / Q000473:pathology; D016481:Helicobacter Infections / Q000276:immunology* / Q000473:pathology*; D016480:Helicobacter pylori / Q000276:immunology* / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology*; D014508:Urea / Q000032:analysis
D000954:Antigens, Surface; D014508:Urea