Elevated Levels of Interferon-γ Are Associated with High Levels of Epstein-Barr Virus Reactivation in Patients with the Intestinal Type of Gastric Cancer

Interferon-gamma plasma levels and presence of mouse mammary tumor virus-like env gene: Implications on the pathogenesis of breast cancer

Mouse mammary tumor virus (MMTV) is a retrovirus that has been associated with the development of breast cancer (BC) in mice. The identification of a 95% homologous gene sequence to MMTV in human BC samples has increased interest in this hypothesis. This virus in humans received the name of mouse mammary tumor virus-like (MMTV-like). Several cytokines may be involved in the interactions between MMTV and the immune system, such as interferon-gamma (IFN-γ), which can enhance Th1-mediated antitumor immune response but it can also play a protumorigenic role by transmitting antiapoptotic and proliferative signals. Little is known about the antiviral immune response in a microenvironment with the presence of MMTV-like in BC patients. Therefore, the purpose of the present study was to quantify the plasma levels of IFN-γ in the peripheral blood of 123 neoplasia-free donors and 98 BC patients of different molecular subtypes, by enzyme-linked immunosorbent assay (ELISA), and evaluate the association of these plasma levels with the detection of the MMTV-like env gene in tumor tissue. Correlation analyzes involving IFN-γ plasma levels and clinical-pathological parameters were performed by Kendall Tau-c test. In our study, a decrease in IFN-γ levels was observed in the group of BC patients (30.85 ± 57.49 pg/ml) compared to the control group (115.00 ± 176.80 pg/ml) (p < 0.0001). In the analysis by stratified BC molecular subtypes, Luminal-A (30.79 ± 61.04 pg/ml; p < 0.0001), Luminal-B (24.74 ± 25.78 pg/ml; p = 0.0188) and triple-negative (23.95 ± 40.45 pg/ml; p = 0.0005) had a lower plasma level compared to control group. There was no significant difference between IFN-γ plasma levels of MMTV-like DNA positive samples compared to MMTV-negative samples (p = 0.2056). In general BC, patients with larger tumor size had higher IFN-γ plasma levels (Tau-c = 0.202; p = 0.019). By analyzing the MMTV-like env negative samples, we could identify that IFN-γ plasma levels were higher in larger tumor size (Tau-c = 0.222; p = 0.020) and with greater lymph node involvement (Tau-c = 0.258; p = 0.042). Also, higher IFN-γ plasma levels were observed in patients with higher histopathological grades (Tau-c = 0.384; p = 0.019) in MMTV-like env positive samples. For the first time, we assessed the association between plasma levels of IFN-γ and the presence of the MMTV-like env gene in BC samples. However, more studies are needed to clarify whether the high levels of IFN-γ in MMTV-like env positive samples are reflecting a possible antiviral immune response or whether this cytokine is promoting tumor growth.

Intersections between innate immune response and gastric cancer development

Worldwide, gastric cancer (GC) is the fifth most commonly diagnosed malignancy. It has a reduced prevalence but has maintained its poor prognosis being the fourth leading cause of deaths related to cancer. The highest mortality rates occur in Asian and Latin American countries, where cases are usually diagnosed at advanced stages. Overall, GC is viewed as the consequence of a multifactorial process, involving the virulence of the Helicobacter pylori (H. pylori) strains, as well as some environmental factors, dietary habits, and host intrinsic factors. The tumor microenvironment in GC appears to be chronically inflamed which promotes tumor progression and reduces the therapeutic opportunities. It has been suggested that inflammation assessment needs to be measured qualitatively and quantitatively, considering cell-infiltration types, availability of receptors to detect damage and pathogens, and presence or absence of aggressive H. pylori strains. Gastrointestinal epithelial cells express several Toll-like receptors and determine the first defensive line against pathogens, and have been also described as mediators of tumorigenesis. However, other molecules, such as cytokines related to inflammation and innate immunity, including immune checkpoint molecules, interferon-gamma pathway and NETosis have been associated with an increased risk of GC. Therefore, this review will explore innate immune activation in the context of premalignant lesions of the gastric epithelium and established gastric tumors.

CMV and EBV Co-Infection in HIV-Infected Children: Infection Rates and Analysis of Differential Expression of Cytokines in HIV Mono- and HIV-CMV-EBV Co-Infected Groups

(1) Background: CMV and EBV co-infections can affect the HIV disease progression by modulating the immune system. The disease dynamics can differ in HIV-positive adults and children. In Pakistan, HIV is rapidly expanding, especially in children; however, the prevalence of CMV and EBV co-infection and the effect on immune modulation in HIV-positive children are not known. This study aimed to bridge this gap by estimating the rate of active CMV and EBV co-infection in HIV-positive children, followed by the analysis of differential expression of cytokines in HIV mono- and HIV/CMV/EBV co-infected children. (2) Methods: DNA samples from 319 HIV-positive children, previously recruited as part of a study to investigate the HIV outbreak in Larkana, Pakistan, in 2019, were screened for CMV and EBV through qPCR. Subsequently, differences in HIV viral loads and CD4 counts were analyzed between the HIV mono- and HIV/CMV/EBV co-infected groups. The RNA samples were used to determine the differential expression of both pro- and anti-inflammatory cytokines in the mono- and co-infected groups using RT-qPCR, while unpaired T-test and Pearson correlation test were applied to, respectively, analyze the differential cytokine expression and correlation between cytokine in the two groups. (3) Results: Of 319 samples, the rate of active EBV and CMV co-infection in HIV-positive children was observed in 79.9% and 38.9%, respectively. A significant difference was observed in HIV viral load between HIV mono- and co-infected groups. IFN-γ expression was found to be lower in the HIV mono-infected group, while higher in all other three co-infected groups. Meanwhile, mRNA expression of TGF-β1 was found to be lower in HIV mono- and HIV-CMV-EBV co-infected groups, while higher in HIV-CMV and HIV-EBV co-infected groups. IFN-γ and IL-2 exhibited a significant positive correlation in all except HIV-CMV co-infected group. (4) Conclusions: The study suggests that the presence of EBV/CMV co-infection can affect the HIV viral loads and expression of certain cytokines (IFN-γ and TGF-β1), which may affect the HIV disease dynamics in infected children.

Bacterial-Viral Interactions in Human Orodigestive and Female Genital Tract Cancers: A Summary of Epidemiologic and Laboratory Evidence

Infectious agents, including viruses, bacteria, fungi, and parasites, have been linked to pathogenesis of human cancers, whereas viruses and bacteria account for more than 99% of infection associated cancers. The human microbiome consists of not only bacteria, but also viruses and fungi. The microbiome co-residing in specific anatomic niches may modulate oncologic potentials of infectious agents in carcinogenesis. In this review, we focused on interactions between viruses and bacteria for cancers arising from the orodigestive tract and the female genital tract. We examined the interactions of these two different biological entities in the context of human carcinogenesis in the following three fashions: (1) direct interactions, (2) indirect interactions, and (3) no interaction between the two groups, but both acting on the same host carcinogenic pathways, yielding synergistic or additive effects in human cancers, e.g., head and neck cancer, liver cancer, colon cancer, gastric cancer, and cervical cancer. We discuss the progress in the current literature and summarize the mechanisms of host-viral-bacterial interactions in various human cancers. Our goal was to evaluate existing evidence and identify gaps in the knowledge for future directions in infection and cancer.

Immune-Proteome Profiling in Classical Hodgkin Lymphoma Tumor Diagnostic Tissue

In classical Hodgkin Lymphoma (cHL), immunoediting via protein signaling is key to evading tumor surveillance. We aimed to identify immune-related proteins that distinguish diagnostic cHL tissues (=diagnostic tumor lysates, n = 27) from control tissues (reactive lymph node lysates, n = 30). Further, we correlated our findings with the proteome plasma profile between cHL patients (n = 26) and healthy controls (n = 27). We used the proximity extension assay (PEA) with the OlinkTM multiplex Immuno-Oncology panel, consisting of 92 proteins. Univariate, multivariate-adjusted analysis and Benjamini–Hochberg’s false discovery testing (=Padj) were performed to detect significant discrepancies. Proteins distinguishing cHL cases from controls were more numerous in plasma (30 proteins) than tissue (17 proteins), all Padj < 0.05. Eight of the identified proteins in cHL tissue (PD-L1, IL-6, CCL17, CCL3, IL-13, MMP12, TNFRS4, and LAG3) were elevated in both cHL tissues and cHL plasma compared with control samples. Six proteins distinguishing cHL tissues from controls tissues were significantly correlated to PD-L1 expression in cHL tissue (IL-6, MCP-2, CCL3, CCL4, GZMB, and IFN-gamma, all p ≤0.05). In conclusion, this study introduces a distinguishing proteomic profile in cHL tissue and potential immune-related markers of pathophysiological relevance.

Recent advances in immune therapies for gastric cancer

Gastric cancer (GC) is an aggressive malignancy that is the third leading cause of cancer mortality worldwide. Localized GC can be cured with surgery, but most patients present with more advanced non-operable disease. Until recently, treatment options for relapsed and refractory advanced GC have been limited to combination chemotherapy regimens, HER-2 directed therapy, and radiation, which lead to few durable responses. Over the past decade, there have been significant advances in our understanding of the molecular and immune pathogenesis of GC. The infectious agents Epstein-Barr virus and Helicobacter pylori perturb the gastric mucosa immune equilibrium, which creates a microenvironment that favors GC tumorigenesis and evasion of immune surveillance. Insights into immune mechanisms of GC have translated into novel therapeutics, including immune checkpoint inhibitors, which have become a treatment option for select patients with GC. Furthermore, chimeric antigen receptor T-cell therapies have emerged as a breakthrough treatment for many cancers, with recent studies showing this to be a potential therapy for GC. In this review, we summarize the current state of knowledge on immune mechanisms of GC and the status of emerging immunotherapies to treat this aggressive cancer, as well as outline current challenges and directions for future research.

The Role of Coinfections in the EBV-Host Broken Equilibrium

The Epstein–Barr virus (EBV) is a well-adapted human virus, and its infection is exclusive to our species, generally beginning in the childhood and then persisting throughout the life of most of the affected adults. Although this infection generally remains asymptomatic, EBV can trigger life-threatening conditions under unclear circumstances. The EBV lifecycle is characterized by interactions with other viruses or bacteria, which increases the probability of awakening its pathobiont capacity. For instance, EBV infects B cells with the potential to alter the germinal center reaction (GCR)—an adaptive immune structure wherein mutagenic-driven processes take place. HIV- and Plasmodium falciparum-induced B cell hyperactivation also feeds the GCR. These agents, along with the B cell tropic KSHV, converge in the ontogeny of germinal center (GC) or post-GC lymphomas. EBV oral transmission facilitates interactions with local bacteria and HPV, thereby increasing the risk of periodontal diseases and head and neck carcinomas. It is less clear as to how EBV is localized in the stomach, but together with Helicobacter pylori, they are known to be responsible for gastric cancer. Perhaps this mechanism is reminiscent of the local inflammation that attracts different herpesviruses and enhances graft damage and chances of rejection in transplanted patients. In this review, we discussed the existing evidence suggestive of EBV possessing the potential to synergize or cooperate with these agents to trigger or worsen the disease.

Serological Evidence for the Association Between Epstein-Barr Virus Infection and Sjögren's Syndrome

Background

Exposure to Epstein-Barr virus (EBV) infection has been hypothesized to be an important risk factor for multiple rheumatic diseases, but the serological evidence so far for its role in Sjögren’s syndrome (SjS) is not clearly established yet. This study aimed to assess the seroepidemiological associations of antibodies to EBV with SjS.

Methods

A seroepidemiological study containing 119 patients with SjS and 65 healthy controls was first performed, in which the associations of SjS with four commonly studied EBV antibodies including IgM-anti-viral capsid antigen (anti-VCA) antibody, IgG-anti-VCA antibody, IgG-anti-early antigen (anti-EA) antibody, and IgG-anti-EBV nuclear antigen 1 (anti-EBNA1) antibody were evaluated. A systematic review and meta-analysis of eligible seroepidemiological studies was also carried out, and data syntheses were performed using random-effect meta-analysis.

Results

In the case-control study, the patients with SjS had both a significantly higher prevalence of IgG-anti-EA antibody positivity (31.9% vs. 3.1%, P < 0.001) and high titers of IgG-anti-EA antibody (P < 0.001) than healthy controls. The titer of IgG-anti-VCA antibody was significantly increased in the patients with SjS compared with healthy controls (P < 0.001). IgG-anti-EA antibody seropositive patients with SjS had lower levels of both C3 (P = 0.002) and C4 (P = 0.02), and the titer of IgG-anti-EA antibody was inversely related to the levels of both C3 (r = -0.31, P < 0.001) and C4 (r = -0.20, P = 0.03). A total of 14 eligible studies on the serological associations between EBV infection and SjS were finally included into the meta-analysis, which suggested obvious associations of SjS with IgM-anti-VCA antibody [Odds ratio (OR) = 5.77, 95%CI 1.73–19.25, P = 0.004] and IgG-anti-EA antibody (OR = 9.97, 95%CI 4.58-21.67, P < 0.00001).

Conclusions

The findings from this study provide strong serological evidence for the association between EBV infection and SjS. SjS has obvious associations with IgM-anti-VCA antibody and IgG-anti-EA antibody. IgG-anti-EA antibody is linked to low levels of C3 and C4 in the patients with SjS, the significance of which needs to be addressed in further studies.

Epstein-Barr Virus and Helicobacter Pylori Co-Infection in Non-Malignant Gastroduodenal Disorders

Epstein–Barr virus (EBV) and Helicobacter pylori (H. pylori) are two pathogens associated with the development of various human cancers. The coexistence of both microorganisms in gastric cancer specimens has been increasingly reported, suggesting that crosstalk of both pathogens may be implicated in the carcinogenesis process. Considering that chronic inflammation is an initial step in the development of several cancers, including gastric cancer, we conducted a systematic review to comprehensively evaluate publications in which EBV and H. pylori co-infection has been documented in patients with non-malignant gastroduodenal disorders (NMGDs), including gastritis, peptic ulcer disease (PUD), and dyspepsia. We searched the PubMed database up to August 2019, as well as publication references and, among the nine studies that met the inclusion criteria, we identified six studies assessing EBV infection directly in gastric tissues (total 949 patients) and three studies in which EBV infection status was determined by serological methods (total 662 patients). Due to the substantial methodological and clinical heterogeneity among studies identified, we could not conduct a meta-analysis. The overall prevalence of EBV + H. pylori co-infection in NMGDs was 34% (range 1.8% to 60%). A higher co-infection rate (EBV + H. pylori) was reported in studies in which EBV was documented by serological methods in comparison with studies in which EBV infection was directly assessed in gastric specimens. The majority of these studies were conducted in Latin-America and India, with most of them comparing NMGDs with gastric cancer, but there were no studies comparing the co-infection rate in NMGDs with that in asymptomatic individuals. In comparison with gastritis caused by only one of these pathogens, EBV + H. pylori co-infection was associated with increased severity of gastric inflammation. In conclusion, only relatively small studies testing EBV and H. pylori co-infection in NMGDs have been published to date and the variable report results are likely influenced by geographic factors and detection methods.

T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus-associated aplastic anemia

Objective: The aim of this study was to analyze T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus (EBV)-associated aplastic anemia (AA).Methods: Sixty AA patients were enrolled, who were in remission following immunosuppressive therapy, including 34 EBV-negative cases and 26 EBV-positive cases. Their complete blood count (CBC), T-lymphocyte subsets, Th1/Th2 cytokines were analyzed. The correlation between EBV-DNA and T-lymphocyte subsets was evaluated, as well as the relationship between EBV-DNA and Th1/Th2 cytokines. The presence of EBV-DNA in peripheral blood mononuclear cells (PBMCs) was also assessed in 60 normal controls.Results: EBV-DNA was detected in 26/60 (43.33%) patients and 21/60 (35.00%) controls. EBV-DNA copy number in AA patients was higher than in controls (Z = -2.138, P = 0.033). The percentage of CD3⁺CD4⁺ T-lymphocytes and the ratio of CD4⁺/CD8⁺ T-lymphocytes in the EBV-negative group were higher than in the EBV-positive group (P = 0.001 and 0.001, respectively). EBV was positively correlated with CD3⁺CD8⁺ T-lymphocyte percentages (Pearson R: 0.496, P = 0.009). Moreover, EBV was positively correlated with IL-10 and IFN-γ levels (Pearson R: 0.559, P = 0.002 and Pearson R: 0.621, P = 0.001, respectively).Conclusions: EBV-DNA copy number in AA patients was higher than in normal controls. Both AA and EBV infection may cause changes in the levels of T-lymphocyte subsets. We recommend monitoring the changes in the immune function and EBV infection simultaneously in AA patients, especially following immunosuppressive therapy.

Epstein-Barr virus reactivation by persistent apical periodontal pathogens

AIM

To assess whether Epstein-Barr virus (EBV) reactivation is triggered by persistent apical periodontitis-related microbes using in vitro and ex vivo methodologies.

METHODOLOGY

Surgically removed human periapical granulomas (n = 50) and healthy gingival tissues (n = 10) were analysed to determine the presence of EBV and seven persistent apical periodontitis-related microbes. In addition, real-time polymerase chain reaction was used to detect the mRNA expression of BZLF-1, an immediate-early gene of EBV. Expression of latent membrane protein (LMP)-1 and ZEBRA, an early lytic protein of EBV encoded by BZLF-1, was also examined using triple-colour immunofluorescence staining. n-Butyric acid produced by the microbes was quantified, and luciferase assays were performed in association with bacterial lysates. In addition, Daudi cells were cultured with bacterial lysates, and the expression levels of BZLF-1 mRNA and ZEBRA protein were determined.

RESULTS

EBV DNA and BZLF-1 mRNA were detected in 47 out of 50 periapical granulomas, but not in healthy gingival tissues. The EBV DNA copy number and the number of Fusobacterium nucleatum were significantly positively correlated with BZLF-1 expression in periapical granulomas. The number of Prevotella intermedia was slightly correlated with BZLF-1 expression; however, the other microbes were not. CD79a-positive B cells in periapical granulomas, but not those in healthy gingival tissues, expressed both LMP-1 and ZEBRA. n-Butyric acid production was the highest in F. nucleatum and the lowest in P. intermedia. Enterococcus faecalis, Candida albicans and the other tested microbes did not produce n-butyric acid. An F. nucleatum lysate exhibited significantly increased BZLF-1-luciferase activity in the same manner of commercial butyric acid, whereas P. intermedia did not. F. nucleatum also induced the expression of BZLF-1 mRNA and ZEBRA protein by Daudi cells, indicating that EBV reactivation was induced.

CONCLUSION

Among the persistent apical periodontitis-related bacteria that were tested, F. nucleatum most strongly reactivated latent EBV, whereas E. faecalis and C. albicans as well as the other microbes did not.