[Does Helicobacter pylori infection play a role in extragastric diseases?]

Association of Helicobacter pylori infection with survival outcomes in advanced gastric cancer patients treated with immune checkpoint inhibitors

Background

Accumulating evidence has revealed that the gut microbiota influences the effectiveness of immune checkpoint inhibitors (ICIs) in cancer patients. As a part of the human microbiome, Helicobacter pylori (H. pylori) was reported to be associated with reduced effectiveness of anti-PD1 immunotherapy in patients with non-small-cell lung cancer (NSCLC). Gastric cancer is more closely related to H. pylori, so we conducted a retrospective analysis to verify whether the association of H. pylori and effectiveness is applicable to advanced gastric cancer (AGC) patients.

Material and methods

AGC patients who had evidence of H. pylori and received anti-PD-1 antibodies were enrolled in the study. The differences in the disease control rate (DCR), overall survival (OS) and progression-free survival (PFS) between the H. pylori-positive group and the negative group were compared.

Results

A total of 77 patients were included in this study; 34 patients were H. pylori positive, and the prevalence of H. pylori infection was 44.2%. Compared with the H. pylori-negative group, patients in the H. pylori-positive group had a higher risk of nonclinical response to anti-PD-1 antibody, with an OR of 2.91 (95% CI: 1.13–7.50). Patients in the H. pylori-negative group had a longer OS and PFS than those in the positive group, with an estimated median OS of 17.5 months vs. 6.2 months (HR = 2.85, 95% CI: 1.70–4.78; P = 0.021) and a median PFS of 8.4 months vs. 2.7 months (HR = 3.11, 95% CI: 1.96–5.07, P = 0.008). Multivariate analysis indicated that H. pylori infection was independently associated with PFS (HR = 1.90, 95% CI: 1.10–3.30; P = 0.022).

Conclusion

Our study unveils for the first time that H. pylori infection is associated with the outcome of immunotherapy for AGC patients. Multicenter, large sample and prospective clinical studies are needed to verify the association.

[New recommendations for the diagnosis and the treatment of Helicobacter pylori infection]

Management of Helicobacter pylori infection is evolving. New data concern the role of the bacterium in various clinical conditions, the indications of H. pylori testing, diagnosis procedures and eradication treatment regimens. H. pylori should be sought and eradicated before starting NSAIDs treatment, in aspirin users with a history of gastroduodenal ulcer, and in patients presenting with chronic dyspepsia, high risk factors of gastric cancer, unexplained iron deficiency anaemia, vitamin B12 deficiency, or immune (idiopathic) thrombocytopenic purpura. The Urea Breath Test remains the best test to diagnose H. pylori infection, whereas serology is the only test, which is not affected by local changes in the stomach. Molecular tests can be used to detect H. pylori and clarithromycin and/or fluoroquinolone resistance in gastric biopsies without necessitating culture. In regions of high clarithromycin resistance, such as France, sequential treatment or bismuth-containing quadruple therapies are replacing standard triple therapies for the first-line empirical treatment.

[Role of Helicobacter pylori infection in iron deficiency anemia]

Anemia induced by digestive diseases refers to anemia due to iron deficiency. Conventional gastrointestinal diagnostic workup fails to establish the cause of iron deficiency in about one third of patients. Abnormal iron absorption is increasingly recognized as an important cause of unexplained iron deficiency. The importance of coeliac disease as a possible cause of iron deficiency anemia refractory to oral iron treatment, without other manifestations of malabsorption syndrome, is increasingly being recognized. In addition, Helicobacter pylori (HP) has been implicated in several recent studies as a cause of iron deficiency anemia (IDA) refractory to oral iron treatment. Cure of previously refractory IDA by HP eradication provides strong evidence supporting a cause-and-effect relationship. In order to establish a cause-and-effect relationship between HP gastritis and IDA, prospective randomized studies comparing the effects of iron administration with or without H. pylorieradication are highly recommended.

Helicobacter pylori seropositivity in fibromyalgia syndrome

Although there are some studies suggesting relation between different types of infection and fibromyalgia syndrome (FM), there is presently no proof that FM is caused by an infection. Helicobacter pylori (HP) infection may cause extragastric manifestations. Inflammation is an important mediator of increased sympathetic nervous system activity and may lead to pain in fibromyalgia patients. In this study, we aimed to investigate the HP seropositivity in fibromyalgia patients compared with controls for possible role of HP infection in FM. Sixty-seven patients with fibromyalgia were evaluated. Two of them were excluded from the study because of high level of acute phase reactants. Sixty-five female patients with fibromyalgia and 41 randomly selected age-matched female healthy controls were enrolled to study. Serum HP IgA and IgG antibodies were measured by enzyme-linked immunosorbent assay technique. Fibromyalgia Impact Questionnaire was assessed in patients and controls. Seropositivity of HP IgG antibody in the fibromyalgia patients was significantly higher than in the control group. No statistically significant differences were found regarding the clinical features between fibromyalgia patients with HP IgG antibody and patients without IgG antibody. Our study suggests that former HP infection may have a role in the etiopathogenesis of fibromyalgia syndrome or may act as a triggering factor. However, high seroprevalence of HP in general population and prevalent asymptomatic infection make it difficult to interpret these results for the definite role of HP in FM. Highlighting the pathophysiologic mechanisms of FM will result in more effective treatment regimens.

Infection by CagA-positive Helicobacter pylori strains may contribute to alter the sperm quality of men with fertility disorders and increase the systemic levels of TNF-alpha

This study was aimed to address the possibility that Helicobacter pylori infection may play a detrimental role in semen quality of men with idiopathic infertility. Infection by H. pylori and by strains expressing CagA was determined in 80 male infertile patients by Western blotting and ELISA. Semen analysis was performed by light microscopy and transmission electron microscopy quantitatively elaborated (fertility index, immaturity, necrosis, and apoptosis percentages). Systemic levels of IL-6 and TNF-alpha were evaluated. Infertile patients infected with H. pylori showed a low sperm quality respective to uninfected patients. Particularly, in CagA-positive patients we observed a significant reduction in sperm motility and in the fertility index, while apoptosis and necrosis were increased. In these patients, the means of systemic TNF-alpha levels were higher than those of uninfected patients. The negative influence of CagA-positive H. pylori infection on sperm quality may help to understand the role of chronic infections in reproductive disorders.

Advances in understanding the association of Helicobacter pylori infection with extragastric diseases

Helicobacter pylori (H. pylori) infection is one of the most common human infections worldwide. It is associated with the development of a number of important upper gastrointestinal (GI) diseases such as chronic gastritis, peptic ulcer and gastric malignancy. At present, there is evidence that H. pylori infection probably plays a critical role in the development of some extragastric diseases. However, there is still controversy over such association. In this article, we will give an overview of the recent advances in understanding the association of H. pylori infection with extragastric diseases.