Validation of a Novel Immunoline Assay for Patient Stratification according to Virulence of the InfectingHelicobacter pyloriStrain and Eradication Status

Abstract

Helicobacter pylori infection shows a worldwide prevalence of around 50%. However, only a minority of infected individuals develop clinical symptoms or diseases. The presence of H. pylori virulence factors, such as CagA and VacA, has been associated with disease development, but assessment of virulence factor presence requires gastric biopsies. Here, we evaluate the H. pylori recomLine test for risk stratification of infected patients by comparing the test score and immune recognition of type I or type II strains defined by the virulence factors CagA, VacA, GroEL, UreA, HcpC, and gGT with patient's disease status according to histology. Moreover, the immune responses of eradicated individuals from two different populations were analysed. Their immune response frequencies and intensities against all antigens except CagA declined below the detection limit. CagA was particularly long lasting in both independent populations. An isolated CagA band often represents past eradication with a likelihood of 88.7%. In addition, a high recomLine score was significantly associated with high-grade gastritis, atrophy, intestinal metaplasia, and gastric cancer. Thus, the recomLine is a sensitive and specific noninvasive test for detecting serum responses against H. pylori in actively infected and eradicated individuals. Moreover, it allows stratifying patients according to their disease state.

Prevalence and associated risk factors of Helicobacter pylori infection in the Wuwei cohort of north‐western China

“…In Egypt, 58% of H. pylori infection cases were reported to be seropositive for CagA [19], and gastric cancer incidence in the country was only 3.4/100 000 [20]. The immune response against type I H. pylori strains significantly increases with advanced histopathology [9]. The type I H. pylori strains may be one of the major factors for the high incidence of gastric cancer in Wuwei City.…”

“…The serological virulent type of the H. pylori strains was determined as described by Formichella et al . [9]. Briefly, type I strain infection cases were seropositive for CagA and/or VacA, while type Ⅱ strain infection cases were seronegative for CagA and VacA.…”

“…The immune response against a more virulent H. pylori strain (type I) is characterised by CagA and/or VacA seropositivity, while that against the less virulent strain (type Ⅱ) is characterised by a lack of immune response towards CagA and VacA. Infections from type I strains can lead to severe stomach disease [9].…”

Detection of Helicobacter Pylori infection by invasive and non-invasive techniques in patients with gastrointestinal diseases from Iraq: A validation study

“…Further, virulence factors have also been present to follow the prognosis of H . pylori infections, such as the presence of serum CagA, VacA, and GroEL antibodies in patients [ 9 ]. However, these serology factors cannot be used to differentiate between asymptomatic colonization status and active infection and either it is past or current H .…”

“…Stool antigen tests lack accuracy because they are influenced by several factors, like antibiotics, proton pump inhibitors (PPIs), N-acetyl cysteine, bowel movements, and upper gastrointestinal bleeding [4,8]. Further, virulence factors have also been present to follow the prognosis of H. pylori infections, such as the presence of serum CagA, VacA, and GroEL antibodies in patients [9]. However, these serology factors cannot be used to differentiate between asymptomatic colonization status and active infection and either it is past or current H. pylori infection, and cannot be used to check the success of eradication of the bacterium [4,10].…”