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Helicobacter pylori--an African perspective
1African Institute of Digestive Diseases, Chris Hani Baragwanath Hospital, Soweto, Johannesburg, South Africa. aidd@netdial.co.za
QJM : Monthly Journal of the Association of Physicians
|October 6, 2001
Summary
Helicobacter pylori infection is common in Africa, but associated diseases like gastric cancer are less frequent. Host immune responses, particularly a Th2-dominant IgG1 response, may protect against severe pathology.
Area of Science:
- Medical Microbiology
- Immunology
- Gastroenterology
Background:
- Helicobacter pylori infection is highly prevalent in Africa, typically acquired during childhood.
- A virulent H. pylori strain (cagA- and vacAS(1)-positive) is common in Soweto.
- H. pylori-associated pathologies show variable and often low prevalence in sub-Saharan Africa, unlike in developed nations.
Purpose of the Study:
- To investigate the reasons behind the divergent prevalence of H. pylori-associated pathology in sub-Saharan Africa compared to developed countries.
- To explore the role of host immune responses in modulating H. pylori's natural history.
Main Methods:
- Analysis of H. pylori prevalence and associated pathology data in African populations.
- Investigation of host immune responses, including IgG subclass patterns, to H. pylori infection.
Main Results:
- While H. pylori infection is ubiquitous, the incidence of duodenal ulcer, gastric ulcer, and gastric cancer is lower than expected in sub-Saharan Africa.
- Progression to atrophic gastritis appears similar to other regions.
- A predominant IgG1 subclass response (suggestive of Th2) to H. pylori was observed, potentially indicating a protective effect.
Conclusions:
- Host immune mechanisms, specifically a Th2-biased response, may play a crucial role in the different clinical outcomes of H. pylori infection in Africa versus developed countries.
- Unidentified factors might inhibit gastric cancer progression despite H. pylori infection.