Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome.
Helicobacter pylori infection is highly prevalent in Chile (73%). Usually a minority of infected patients develops complications such as ulcers and gastric cancer that have been associated with the presence of virulence factors (cagA, vacA) and host T helper response (Th1/Th2). Our aim was to evaluate the relationship between strain virulence and host immune response, using a multiple regression approach for the development of a model based on data collected from H. pylori infected patients in Chile. We analyzed levels of selected cytokines determined by ELISA (interleukin (IL)-12, IL-10, interferon (IFN)-gamma and IL-4) and the presence of cagA and vacA alleles polymorphisms determined by PCR in antral biopsies of 41 patients referred to endoscopy. By multiple regression analysis we established a correlation between bacterial and host factors using clinical outcome (gastritis and duodenal ulcer) as dependent variables. The selected model was described by: clinical outcome=0.867491 (cagA)+0.0131847 (IL-12/IL-10)+0.0103503 (IFN-gamma/IL-4) and it was able to explain over 90% of clinical outcomes observations (R(2)=96.4). This model considers that clinical outcomes are better explained by the interaction of host immune factors and strain virulence as a complex and interdependent mechanism.
Serrano
Carolina
C
Department of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Lira 85, Santiago, Chile.
Diaz
Maria Ines
MI
Valdivia
Alejandra
A
Godoy
Alex
A
Peña
Alfredo
A
Rollan
Antonio
A
Kirberg
Arturo
A
Hebel
Eduardo
E
Fierro
Jaqueline
J
Klapp
Gabriela
G
Venegas
Alejandro
A
Harris
Paul R
PR
D000293:Adolescent; D000328:Adult; D000483:Alleles; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000276:immunology*; D004381:Duodenal Ulcer / Q000276:immunology / Q000821:virology; D005260:Female; D005756:Gastritis / Q000276:immunology / Q000821:virology; D016481:Helicobacter Infections / Q000276:immunology* / Q000821:virology*; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D037521:Virulence Factors / Q000235:genetics*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016207:Cytokines; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori