CagA and VacA: virulence factors of Helicobacter pylori in Thai patients with gastroduodenal diseases.
BACKGROUND
The aim of this study was to assess the seroprevalence of cytotoxin-associated gene A (cagA) and vacuolating cytotoxin gene A (vacA) of Helicobacter pylori in selected Thai populations with specific gastroduodenal diseases.


METHODS
The immunoblot assay was used to detect serum antibodies against CagA and VacA obtained from the following patients: 87 cases of nonulcer dyspepsia (NUD), 61 cases of duodenal ulcer (DU), 49 cases of gastric ulcer (GU), and 10 cases of gastric cancer (GC).


RESULTS
Serum antibodies to CagA were detected in 75.4% of all patients (70. 1% of NUD, 78.7% of DU, 77.6% of GU, and 90% of GC). Although the prevalence of CagA seropositivity in GC patients was higher than in the other three groups, the difference was not statistically significant (p >.05).


CONCLUSIONS
The high seroprevalence of the CagA-positive H. pylori strain in patients with peptic ulcer, GC, and NUD indicates that this strain is common in Thai patients with gastroduodenal diseases. Furthermore, phenotypic classification of H. pylori into type 1 (CagA-positive, VacA-positive) and type 2 (CagA-negative, VacA-negative) is not a useful marker for screening patients with severe forms of gastroduodenal diseases.
Mahachai
V
V
Gastroenterology Unit, Department of Internal Medicine, Chulalongkorn University Hospital, Bangkok, Thailand. fmedvmc@md2.md.chula.ac.th
Tangkijvanich
P
P
Wannachai
N
N
Sumpathanukul
P
P
Kullavanijaya
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000276:immunology*; D004381:Duodenal Ulcer / Q000382:microbiology; D004415:Dyspepsia / Q000382:microbiology; D005260:Female; D005767:Gastrointestinal Diseases / Q000382:microbiology*; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D013274:Stomach Neoplasms / Q000382:microbiology; D013276:Stomach Ulcer / Q000382:microbiology; D013785:Thailand / Q000453:epidemiology; D014774:Virulence
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori