IgG subclass responses in childhood Helicobacter pylori duodenal ulcer: evidence of T-helper cell type 2 responses.
BACKGROUND
Duodenal ulcer in adults chronically infected with Helicobacter pylori is associated with a polarized T-helper cell type 1 (Th1) mucosal immune response, with a predominantly immunoglobulin G2 (IgG2) systemic specific response. It has been suggested that children colonized by H. pylori also produce a mucosal Th1 response, but there are few studies that have measured IgG subclass responses in children with duodenal ulcer.


METHODS
Seven children with endoscopically proven duodenal ulcer and H. pylori infection and 18 children with biopsy proven H. pylori infection but no duodenal ulcer had relative concentrations of IgG subclass responses (IgGsc) against H. pylori antigens measured by ELISA. Eighteen IgG seropositive adults acted as controls. The range of antigens recognised by IgG1 and IgG2 subclass responses were investigated by Western blots.


RESULTS
There were no differences in mean IgGsc responses between children with or without duodenal ulcer. Adults produced an IgG2 predominant response. Western blots showed no qualitative differences in antigens recognised by IgG1 or IgG2.


CONCLUSIONS
Children with duodenal ulcer, in contrast to adults, produce an IgGsc response consistent with a mucosal Th2 response to H. pylori regardless of the presence of duodenal ulceration. This suggests that disease causation amongst children with H. pylori associated duodenal ulceration may not be dependant upon a mucosal Th1 biased response.
Paediatric and Life Course Epidemiology Research Group, School of Clinical and Medical Sciences (Child Health), University of Newcastle-upon-Tyne, Royal Victoria Infirmary, UK. d.i.campbell@ncl.ac.uk
David I
DI
Campbell
Mark S
MS
Pearce
Louise
L
Parker
Julian E
JE
Thomas
D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004381:Duodenal Ulcer / Q000276:immunology* / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D018928:Immunity, Mucosal; D007074:Immunoglobulin G / Q000097:blood*; D018418:Th2 Cells / Q000276:immunology*
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G