Validation of a Novel Immunoline Assay for Patient Stratification according to Virulence of the Infecting Helicobacter pylori Strain and Eradication Status

Analyses of the association between Helicobacter pylori antibody titre and pathogenicity before and after eradication: results of the Kyushu and Okinawa population study, a retrospective observational cohort study

OBJECTIVES

To assess the utility of Helicobacter pylori antibody testing, we evaluated the correlation between the H. pylori antibody titre and H. pylori-associated pathogenicity and the changes in antibody titre after H. pylori eradication therapy.

DESIGN

A retrospective observational cohort study.

SETTING AND PARTICIPANTS

From 2004 to 2016, medical check-ups were performed in different regions of Japan. In total, 324 subjects infected with H. pylori who received H. pylori eradication therapy were enrolled; H. pylori was eradicated in 266 of these subjects. We examined the associations between H. pylori antibody titre with pepsinogen and the presence or absence of H. pylori-associated pathogenic proteins, such as cytotoxin-associated gene A and vacuolating cytotoxin gene A, at baseline and after H. pylori eradication therapy.

RESULTS

The H.pylori antibody titre showed a positive correlation with pepsinogen II and a negative correlation with the pepsinogen I/II ratio. Moreover, the H.pylori antibody titre significantly correlated with the positive rates of H. pylori-associated pathogenic protein before eradication therapy. Antibody titres decreased after eradication, the pepsinogen I/II ratio increased and the H. pylori-associated pathogenic protein-positive rate decreased in patients with successful eradication. The determination of eradication using the decline in antibody titre 6 months after eradication therapy was useful (area under the receiver operating characteristic curve: 0.98).

CONCLUSIONS

Our data indicate that the H. pylori antibody titre may represent the degree of pathogenicity. The H. pylori antibody titre was associated with attenuation of pathogenicity in patients with H. pylori eradication, indicating the clinical utility of H. pylori antibody testing.

A multiserological line assay to potentially discriminate current from past Helicobacter pylori infection

OBJECTIVES

Early diagnosis is important in controlling Helicobacter pylori-induced gastritis and progression to gastric malignancy. Serological testing is an efficient non-invasive diagnostic method, but currently does not allow differentiation between active and past infections. To fill this diagnostic gap we investigated the diagnostic value of a panel of ten H. pylori-specific antibodies in individuals with different H. pylori infection status within a German population.

METHODS

We used the recomLine Helicobacter IgG 2.0 immunoblotting assay to analyse ten H. pylori-specific antibodies in serum samples collected from 1108 volunteers. From these, 788 samples were used to build exposure and infection status models and 320 samples for model validation. H. pylori infection status was verified by histological examination. We applied logistic regression to select antibodies correlated to infection status and developed, with independent validation, discriminating models and risk scores. Receiving operating characteristic analysis was performed to assess the accuracy of the discriminating models.

RESULTS

Antibody reactivity against cytotoxin-associated gene A (CagA), H. pylori chaperone (GroEL), and hook-associated protein 2 homologue (FliD) was independently associated with the risk of H. pylori exposure with ORs and 95% CIs of 99.24 (46.50-211.80), 46.17 (17.45-122.17), and 22.16 (8.46-55.04), respectively. A risk score comprising these three selected antibodies differentiated currently H. pylori infected or eradicated participants from negatives with an area under the curve of 0.976 (95% CI: 0.965-0.987) (Model 1). Seropositivity for vacuolating cytotoxin A (VacA), GroEL, FliD, H. pylori adhesin A (HpaA), and γ-glutamyl transpeptidase (gGT) was associated with a current infection with an area under the curve of 0.870 (95% CI: 0.837-0.903), which may help discriminate currently infected patients from eradicated ones (Model 2).

DISCUSSION

The recomLine assay is sensitive and specific in determining H. pylori infection and eradication status and thus represents a valuable tool in the management of H. pylori infection.

Urolithin A Attenuates Helicobacter pylori-Induced Damage In Vivo

Urolithin A (UA) is a metabolite produced in the gut following the consumption of ellagic acid (EA) rich foods. EA has shown anti-inflammatory, antioxidant, and anticancer properties. Because EA is poorly absorbed in the gastrointestinal tract, urolithins are considered to play a major role in bioactivity. Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection all over the world. It is potentially hazardous to humans because of its relationship to various gastrointestinal diseases. In this study, we investigated the effect of UA on inflammation by H. pylori. The results indicated that UA attenuated H. pylori-induced inflammation in vitro and in vivo. UA also reduced the secretion of H. pylori virulence factors and tissue injuries in mice. Furthermore, UA decreased the relative abundance of Helicobacteraceae in feces of H. pylori-infected mice. In summary, taking UA effectively inhibited the injury caused by H. pylori.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Helicobacter pylori serology is associated with worse overall survival in patients with melanoma treated with immune checkpoint inhibitors

The microbiome is now regarded as one of the hallmarks of cancer and several strategies to modify the gut microbiota to improve immune checkpoint inhibitor (ICI) activity are being evaluated in clinical trials. Preliminary data regarding the upper gastro-intestinal microbiota indicated that Helicobacter pylori seropositivity was associated with a negative prognosis in patients amenable to ICI. In 97 patients with advanced melanoma treated with ICI, we assessed the impact of H. pylori on outcomes and microbiome composition. We performed H. pylori serology and profiled the fecal microbiome with metagenomics sequencing. Among the 97 patients, 22% were H. pylori positive (Pos). H. pylori Pos patients had a significantly shorter overall survival (p = .02) compared to H. pylori negative (Neg) patients. In addition, objective response rate and progression-free survival were decreased in H. pylori Pos patients. Metagenomics sequencing did not reveal any difference in diversity indexes between the H. pylori groups. At the taxa level, Eubacterium ventriosum, Mediterraneibacter (Ruminococcus) torques, and Dorea formicigenerans were increased in the H. pylori Pos group, while Alistipes finegoldii, Hungatella hathewayi and Blautia producta were over-represented in the H. pylori Neg group. In a second independent cohort of patients with NSCLC, diversity indexes were similar in both groups and Bacteroides xylanisolvens was increased in H. pylori Neg patients. Our results demonstrated that the negative impact of H. pylori on outcomes seem to be independent from the fecal microbiome composition. These findings warrant further validation and development of therapeutic strategies to eradicate H. pylori in immuno-oncology arena.

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

There is still no agreement on the gold standard technique for diagnosing of H. Pylori in Iraq, as well as a paucity of data on the validity of different diagnostic techniques. This study aimed to investigate the prevalence of this bacterium with different methods and compare them to the quantitative polymerase chain reaction (qPCR) as a golden standard technique among Iraqi patients. In total, 115 Iraqi patients strongly suspected of H. pylori infection were enrolled in the current study. Invasive techniques including rapid urease testing (RUT) and gastric tissue culture in addition to non-invasive techniques including 14C-Urea breath test (14C-UBT), stool antigen test (SAT), CagA-IgG serology, and qPCR were performed to confirm the H. pylori infection. The qPCR was used as the gold standard to estimate the sensitivity, specificity, positive and negative predictive values for the studied diagnostic tests. Overall, the prevalence rate of H. pylori in Iraqi patients was ranged from 47.8 to 70.4% using different methods. The positive results for each test were as follows: qPCR 81, (70.4%) UBT 79 (68.7%), SAT 77 (67%), RUT 76 (66.1%), Cag-IgG 61 (53%), and culture 55 (47.8%). The 14C-UBT showed the highest overall performance with 97.5% sensitivity, 97% specificity, and total accuracy of 97.3% followed by SAT, RUT, Cag-IgG, and culture method. Based on the accuracy of the studied methods for H. pylori detection, they can be arranged in order as follows: qPCR > UBT > SAT > RUT> CagA IgG > culture. Since a universal gold standard assay for the diagnosis of H. pylori has not yet been established in Iraq, the UBT may be recommended as first choice due to its higher performance compared to other methods.

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

OBJECTIVES

To evaluate the prevalence of Helicobacter pylori infection and risk factors and to serotype the strains in Wuwei, located in north-western China, which has a high incidence of gastric cancer.

METHODS

Helicobacter pylori infection was analysed in 21 291 adults by ¹⁴ C-urea breath test, and H. pylori antibody were detected in 9183 serum samples by latex immunoturbidimetric method. The correlation of H. pylori infection with demographic-economic, lifestyle factors and medical history among the participants was determined by questionnaire. The antibodies against H. pylori urease, VacA and CagA in serum were determined by dot immunobinding assay.

RESULTS

The infection rate of H. pylori was 53.0%, and 90.1% of strains were type I strains. The H. pylori infection rate was higher among farmers (OR = 1.34, 95% CI: 1.19-1.50) and individuals who had a junior high school or higher education level (OR = 1.10, 95% CI: 1.06-1.15), and was lower in older individuals (OR = 0.86, 95% CI: 0.83-0.90), individuals with high income (OR = 0.93, 95% CI: 0.90-0.95), individuals with a habit of eating quickly (OR = 0.93, 95% CI: 0.87-0.99) and individuals who consumed more fruit and vegetables (OR = 0.90, 95% CI: 0.85-0.95). Individuals with history of cholecystitis/cholecystolithiasis, hypertension and asthma were negatively correlated with H. pylori infection (P < 0.05).

CONCLUSION

The prevalence of H. pylori infection is high in Wuwei. The major prevalent strain is type I strain. Age, education, occupation, household income, consumption of fruit and vegetables, and habit of eating quickly are independent risk factors for H. pylori infection, which is also associated with individuals with a history of extragastric diseases.

Performance of multiplex serology in discriminating active vs past Helicobacter pylori infection in a primarily African American population in the southeastern United States

PURPOSE

To feasibly analyze associations of Helicobacter pylori (H. pylori) with disease in large cohort studies, assays are needed to assess H. pylori prevalence in existing biospecimens. However, serology has traditionally been unable to distinguish active from past infection. We sought to determine the sensitivity of seropositivity to H. pylori proteins to detect active infection.

METHODS

We measured antibody responses to 13 H. pylori proteins using multiplex serology in serum samples of a training (n = 78) and validation set (n = 49) collected concurrently from patients undergoing urea breath test (UBT). To determine sensitivity of seropositivity to H. pylori proteins for active infection, a cutoff was applied to achieve 90% specificity. Antibody levels were retested in a subset of participants (n = 16) 6 months after baseline.

RESULTS

With a specificity of 91%, seropositivity to H. pylori proteins VacA, GroEl, HcpC, and HP1564 ascertained active infection from 100% to 75% sensitivity. Positivity to a combination of these proteins (≥2 out of the 4) resulted in specificity of 90% and sensitivity of 100%. The validation set replicated results from the training set. Among those participants with successful H. pylori eradication after baseline, antibody levels decreased significantly for VacA, HcpC, and HP1564 when assessed 6 months later.

CONCLUSION

Utilizing the cutoffs for seropositivity established through comparison with UBT, seropositivity to ≥2 of the H. pylori proteins VacA, GroEl, HcpC, and HP1564 determines active H. pylori infection at high specificity and sensitivity and may approximate the prevalence of active H. pylori infection in large cohorts.