Importance of Helicobacter pylori oipA in clinical presentation, gastric inflammation, and mucosal interleukin 8 production.
OBJECTIVE
Disease-associated virulence factors of Helicobacter pylori may not be independent of one another. The aim was to determine which H. pylori virulence factor(s) was the most important predictor of severity of gastric inflammation or clinical outcome.


METHODS
cag Pathogenicity island (PAI), vacA babA2, and iceA status were determined by polymerase chain reaction (PCR). oipA functionality was based on switch status determined by PCR-based sequencing. A backward stepwise multiple regression analysis was performed to determine which factor(s) was the most discriminating for clinical outcome as well as the relationship to mucosal histology (H. pylori density, neutrophil infiltration, intestinal metaplasia, and gastric atrophy) and mucosal interleukin 8 (IL-8) production.


RESULTS
H. pylori were obtained from 247 patients (86 with gastritis, 86 with duodenal ulcer, and 75 with gastric carcinoma). Although oipA status was closely linked to specific cag PAI, vacA, and babA2 genotypes, only oipA status remained in the final model to discriminate duodenal ulcer from gastritis (adjusted odds ratio [OR] = 5 and 95% confidence interval [CI] = 2.1-11.9). Among the factors, only a functional oipA was significantly associated with high H. pylori density, severe neutrophil infiltration, and high mucosal IL-8 levels (P < 0.001). oipA status had no relationship to gastric atrophic changes.


CONCLUSIONS
oipA functional status was related to clinical presentation, H. pylori density, and gastric inflammation. cag PAI, babA2, or vacA status appear important only as surrogate markers for a functional oipA gene.
Yamaoka
Yoshio
Y
Department of Medicine, Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas 77030, USA. yyamaoka@bcm.tmc.edu
Kikuchi
Shogo
S
el-Zimaity
Hala M T
HM
Gutierrez
Oscar
O
Osato
Michael S
MS
Graham
David Y
DY
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology*; D001483:Base Sequence; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism* / Q000473:pathology; D005756:Gastritis / Q000209:etiology*; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000209:etiology*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011706:Pyloric Antrum; D014774:Virulence
D001425:Bacterial Outer Membrane Proteins; D016209:Interleukin-8