title: Phenotypic study of peripheral blood lymphocytes and humoral immune response in Helicobacter pylori infection according to age.
abstract: 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.
authors.affiliation: Laboratory of Research in Bacteriology, Universidade Federal de Minas Gerals, Belo Horizonte, Brazil.
authors.forename: T F
authors.initials: TF
authors.lastname: Soares
authors.forename: G A
authors.initials: GA
authors.lastname: Rocha
authors.forename: A M C
authors.initials: AM
authors.lastname: Rocha
authors.forename: R
authors.initials: R
authors.lastname: Corrêa-Oliveira
authors.forename: O A
authors.initials: OA
authors.lastname: Martins-Filho
authors.forename: A S T
authors.initials: AS
authors.lastname: Carvalho
authors.forename: P
authors.initials: P
authors.lastname: Bittencourt
authors.forename: C A
authors.initials: CA
authors.lastname: Oliveira
authors.forename: A M C
authors.initials: AM
authors.lastname: Faria
authors.forename: D M M
authors.initials: DM
authors.lastname: Queiroz
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D016130:Immunophenotyping; D016131:Lymphocyte Subsets / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D015703:Antigens, CD; D007074:Immunoglobulin G