Background H. pylori infection is acquired during childhood and causes a chronic inflammatory response in the gastric mucosa, which is considered the main risk factor to acquire gastric cancer (GC) later in life. More recently, infection by Epstein-Barr virus (EBV) have also been associated with GC. The role of EBV in early inflammatory responses and its relationship with H. pylori infection remains poorly studied. Here, we assessed whether EBV infection in children correlated with the stage of gastritis and whether co-infection with H. pylori affected the severity of inflammation.Methodology/Principal Findings333 pediatric patients with chronic abdominal pain were studied. From them, gastric biopsies were taken and inflammation graded according to the Sydney system; peripheral blood was drawn and antibodies against EBV (IgG and IgM anti-VCA) and H. pylori (IgG anti-whole bacteria and anti-CagA) were measured in sera. We found that children infected only by EBV presented mild mononuclear (MN) and none polymorphonuclear (PMN) cell infiltration, while those infected by H. pylori presented moderate MN and mild PMN. In contrast, patients co-infected with both pathogens were significantly associated with severe gastritis. Importantly, co-infection of H. pylori CagA+/EBV+ had a stronger association with severe MN (PR 3.0) and PMN (PR 7.2) cells than cases with single H. pylori CagA+ infection.Conclusions/SignificanceCo-infection with EBV and H. pylori in pediatric patients is associated with severe gastritis. Even single infections with H. pylori CagA+ strains are associated with mild to moderate infiltration arguing for a cooperative effect of H. pylori and EBV in the gastric mucosa and revealing a critical role for EBV previously un-appreciated. This study points out the need to study both pathogens to understand the mechanism behind severe damage of the gastric mucosa, which could identified children with increased risk to present more serious lesions later in life.

Background:Chronic tissue damage induced by Helicobacter pylori (HP)-driven inflammation is considered the main risk of gastric carcinoma (GC). Epstein–Barr virus (EBV) infection has also been associated with GC. In this study, we aim to address the role of EBV in inflammatory GC precursor lesions and its added risk to HP infection.Methods:Antibodies against EBV, HP and the bacterial virulence factor CagA were measured in sera from 525 Mexican and Paraguayan patients with gastric disease. Gastric samples were characterised according to the updated Sydney classification and associations were estimated between antibody responses and severity of both tissue damage and inflammation.Results:We found significant associations (odd ratios and trends) between EBV and HP copositivity and premalignant lesions and intestinal-type GC. The EBV and HP coinfection was also significantly associated with increased infiltration of immune cells. No association was found between EBV and the less inflammation-driven diffuse-type GC.Conclusions:Our study suggests that EBV co-participates with HP to induce severe inflammation, increasing the risk of progression to intestinal-type GC.

Helicobacter pylori is a Gram-negative bacterium that colonizes the human gastric mucosa and is responsible for causing peptic ulcers and gastric carcinoma. The expression of virulence factors allows the persistence of H. pylori in the stomach, which results in a chronic, sometimes uncontrolled inflammatory response. Type II toxin–antitoxin (TA) systems have emerged as important virulence factors in many pathogenic bacteria. Three type II TA systems have previously been identified in the genome of H. pylori 26695: HP0315–HP0316, HP0892–HP0893, and HP0894–HP0895. Here we characterized a heretofore undescribed type II TA system in H. pylori, HP0967–HP0968, which is encoded by the bicistronic operon hp0968–hp0967 and belongs to the Vap family. The predicted HP0967 protein is a toxin with ribonuclease activity whereas HP0968 is an antitoxin that binds to its own regulatory region. We found that all type II TA systems were expressed in H. pylori during early stationary growth phase, and differentially expressed in the presence of urea, nickel, and iron, although, the hp0968–hp0967 pair was the most affected under these environmental conditions. Transcription of hp0968–hp0967 was strongly induced in a mature H. pylori biofilm and when the bacteria interacted with AGS epithelial cells. Kanamycin and chloramphenicol considerably boosted transcription levels of all the four type II TA systems. The hp0968–hp0967 TA system was the most frequent among 317 H. pylori strains isolated from all over the world. This study is the first report on the transcription of type II TA genes in H. pylori under different environmental conditions. Our data show that the HP0967 and HP0968 proteins constitute a bona fide type II TA system in H. pylori, whose expression is regulated by environmental cues, which are relevant in the context of infection of the human gastric mucosa.

Background. Helicobacter pylori (HP) infection and nonsteroidal anti-inflammatory drugs (NSAID) use are considered the main risk to develop peptic ulcer disease (PUD). However, PUD also occurs in the absence of HP infection and/or NSAID use. Recently, we have found evidence that Epstein-Barr virus (EBV) reactivation increases the risk to develop premalignant and malignant gastric lesions. Objective. To study a possible association between EBV and PUD. Methods. Antibodies against an EBV reactivation antigen, HP, and the HP virulence factor CagA were measured in sera from 207 Mexican subjects, controls (healthy individuals, n = 129), and PUD patients (n = 78, 58 duodenal and 20 gastric ulcers). Statistical associations were estimated. Results. Duodenal PUD was significantly associated with high anti-EBV IgG titers (p = 0.022, OR = 2.5), while anti-EBV IgA was positively associated with gastric PUD (p = 0.002, OR = 10.1). Conclusions. Our study suggests that EBV reactivation in gastric and duodenal epithelium increases the risk to develop PUD.

Background The inflammatory response directed against Helicobacter pylori (HP) is believed to be one of the main triggers of the appearance of gastric lesions and their progression to gastric cancer (GC). Epstein-Barr virus (EBV) has been found responsible for about 10% of all GCs, but the inflammatory response has not been studied in GC patients with evidence of high levels of EBV reactivation. Objective To determine the relationship between inflammation and antibodies against EBV reactivation antigens, HP, and the bacterium virulence factor CagA in patients with GC. Methods 127 GC patients, 46 gastritis patients, and 197 healthy subjects were studied. IL-1β, IL-6, IL-8, IL-10, TNF-α, TGF-β, MCP-1, and IFN-γ levels were measured in serum or plasma and compared against the antibody titers of VCA-IgG, HP, and the HP virulence factor CagA. Statistical associations were estimated. Results Significant ORs and positive trends were found between VCA-IgG and IFN-γ, specifically for patients with GC of intestinal type (OR: 6.4, 95% C.I. 1.2–35.4) (p < 0.044). Conclusions We confirmed a positive association between a marker of EBV reactivation and intestinal gastric cancer and present evidence of a correlation with elevated serum levels of IFN-γ, but not with the other cytokines.