CagA Antibodies as a Marker of Virulence in Chilean Patients With Helicobacter pylori Infection

Abstract

In Chile, patients infected with H. pylori have a proportion of CagA-positive strains similar to that reported in developed countries. CagA prevalence was not significantly different in adults and children infected with H. pylori, suggesting that variations in clinical outcome may be related to host immune or environmental factors.

Role of childhood infection in the sequelae of H. pylori disease

“…13,14 A consequence of the reduced gastric response in infected children is the absence or near absence of gastric ulceration in this age group. [16][17][18][19] Regarding duodenal ulceration, in one of the largest prospective studies to date of children with proven H. pylori infection, 19 we detected duodenal ulcer in 3.1% of the children, a prevalence considerably lower than the reported 14-15% prevalence in infected adults. 20 In a separate study comparing children and adults referred to our tertiary medical center in Santiago, Chile for severe gastrointestinal symptoms, ulceration (predominantly duodenal) was present in 22% of H. pylori-infected children under 13 y of age compared with 47% of adults (P < 0.05).…”

CagA positivity and its association with gastroduodenal disease in Turkish children undergoing endoscopic investigation

“…It has been reported that CagA-bearing HP strains are more virulent and cause more severe gastroduodenal disease. 8,9 In contrast, some authors have reported that mucosal injury might not be affected by strains of HP. 10,11 Serologic studies in developed countries have shown an increased prevalence of antibody to the CagA antigen in peptic ulcer disease and gastric cancer patients compared with in infected but healthy patients.…”

Gastric Cancer is Related to Early Helicobacter pylori Infection in a High-Prevalence Country

“…The cutoff values were based on the standard value of the test calibrators, according to the instructions of the manufacturer, and expressed as arbitrary units per milliliter. In a preliminary study, we evaluated immune response to H. pylori through the measurement of specific antibodies directed against a whole cell preparation of H. pylori with a noncommercial immunoassay (15). Serum positivity on that study was defined on the basis of cutoff values established by the mean + 3 SD of a normal population from the United States.…”