H. Pylori VacA and CagA Line Test: A New Test for The Detection of the Virulent Strains
Helicobacter pylori (H.Pylori) infects at least 50% of the world's human population. Infection by H. Pylori is associated with the development of chronic gastritis, gastric or duodenal ulcer, gastric cancer and MALT-lymphoma. It is classified by WHO as class I carcinogen. Virulence genes have been described in H. Pylori infection known as CagA and VacA that are associated only with virulent strains
The cytotoxin-associated gene (CagA) is considered a usefull marker for the virulent strains associated withpeptic ulcer and it has been found that 95% of patients with peptic ulcer were CagA positive.
The vacuolating cytotoxin gene (vacA) is an important virulence factor that is linked to gastric carcinoma. VacA enhances hyper-proliferative response, altering the balance of gastric homeostasis, changing gastric epithelial cell turnover and permits the presence of mutated cells.
Studies have found that 91% of patients with gastric carcinoma were VacA seropositive and that 80% of them were CagA positive.
This LINE test can be used to screen dyspeptic patients who are carrying cagA and vacA and are at risk of developing gastric and duodenal ulcers as well as cancer. Hence, the LINE test is considered a part of a "Test and Treat Strategy"
It is also used for pediatrics H. pylori infection diagnosis particularly in developing countries. In Egypt 72% of children over the age of 5 years are infected with H.pylori.
Immunoblotting test is the technique used in our lab for Identification of VacA and CagA, using a fasting serum sample.
The result is available after 3 days.