Effective eradication of Helicobacter pylori infection has often proved more difficult than expected.
| There was a reduction in secretion of IL-4 from blood T cells in subjects failing to eradicate H. pylori.|
|American Journal of Gastroenterology|
Antimicrobial resistance incompletely explains eradication failure.
In this study, a research team from Australia assessed whether an impaired immune response contributes to failed eradication after standard antibiotic therapy.
The team assessed host immunity as blood T lymphocyte production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), being surrogate markers of mucosal Th1 and Th2 responses, respectively.
The validity of using circulating T cell cytokines as surrogate markers of mucosal immunity was established.
The team recruited a total of 52 dyspeptic patients and 11 patients with previous H. pylori eradication failure into the study.
They found no significant difference in secretion of IFN-gamma from peripheral blood T cells, in either unstimulated or antigen-stimulated cultures, between clinical groups.
However, they identified a significant reduction in secretion of IL-4 from blood T cells in subjects failing to eradicate H. pylori, compared with those who successfully eradicated the infection in both unstimulated and stimulated cultures.
A significant difference in IL-4 secretion was also detected in antigen-stimulated cultures compared with that in H. pylori-positive subjects (p < 0.05).
The researchers detected low levels of IL-4 secretion, irrespective of the number of courses of antibiotic therapy.
Furthermore, lower levels of IgG anti-H. pylori antibody were detected in both serum and saliva of subjects with persistent infection after use of antibiotics, compared with untreated H. pylori-positive subjects.
Dr Tom Borody’s team concluded, “These results support the hypothesis that impaired mucosal immunity, particularly involving the secretion of IL-4, may contribute to H. pylori eradication failure”.
“Measurement of whole blood secretion of IL-4 may predict which patients are more likely to fail standard antibiotic therapy”.