Evaluation of the clinical significance of homB, a novel candidate marker of Helicobacter pylori strains associated with peptic ulcer disease.
BACKGROUND
homB codes for a putative Helicobacter pylori outer membrane protein and has previously been associated with peptic ulcer disease (PUD) in children.


METHODS
A total of 190 H. pylori strains isolated from children and adults were studied to evaluate the clinical importance of the homB gene. In vitro experiments were performed to identify HomB mechanisms of bacterial pathogenicity.


RESULTS
Characterization of the isolates demonstrated that homB was significantly associated with PUD in 86 children (odds ratio [OR], 7.64 [95% confidence interval {CI}, 2.65-22.05]) and in 32 adults < or =40 years of age (OR, 11.25 [95% CI, 1.86-68.13]). homB was correlated with the presence of cagA, babA2, vacAs1, hopQI, and oipA "on" genotype (P< .001) The HomB protein was found to be expressed in the H. pylori outer membrane and was noted to be antigenic in humans. H. pylori homB knockout mutant strains presented reduced ability to induce interleukin-8 secretion from human gastric epithelial cells, as well as reduced capacity to bind to these cells. Both of these functions correlated with the number of homB copies present in a strain.


CONCLUSIONS
homB can be considered a comarker of H. pylori strains associated with PUD. Moreover, results strongly suggest that HomB is involved in the inflammatory response and in H. pylori adherence, constituting a novel putative virulence factor.
Oleastro
Mónica
M
Departamento de Doenças Infecciosas, Instituto Nacional Saúde Dr Ricardo Jorge, Lisbon, Portugal. francis.megraud@chu-bordeaux.fr
Cordeiro
Rita
R
Ferrand
Jonathan
J
Nunes
Baltazar
B
Lehours
Philippe
P
Carvalho-Oliveira
Isabel
I
Mendes
Ana I
AI
Penque
Deborah
D
Monteiro
Lurdes
L
Mégraud
Francis
F
Ménard
Armelle
A
D000328:Adult; D000942:Antigens, Bacterial; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D002648:Child; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005819:Genetic Markers; D014644:Genetic Variation; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D010437:Peptic Ulcer / Q000382:microbiology*; D014774:Virulence
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D005819:Genetic Markers; D016209:Interleukin-8