Distinctive EBV infection characteristics in children from a developing country

Liver injury and prolonged hospitalization as indicators of severity in patients with adenovirus infections

BACKGROUND

Adenovirus (ADV) is a prevalent infective virus in children, accounting for around 5-10% of all cases of acute respiratory illnesses and 4-15% of pneumonia cases in children younger than five years old. Without treatment, severe ADV pneumonia could result in fatality rates of over 50% in cases of emerging strains or disseminated disease. This study aims to uncover the relationship of clinical indicators with primary ADV infection severity, regarding duration of hospitalization and liver injury.

METHODS

In this retrospective study, we collected and analyzed the medical records of 1151 in-patients who met the inclusion and exclusion criteria. According to duration of hospitalization, all patients were divided into three groups. Then the difference and correlation of clinical indicators with ADV infection were analyzed, and the relationship among liver injury, immune cells and cytokines was evaluated.

RESULTS

The study revealed that patients with a duration of hospitalization exceeding 14 days had the highest percentage of abnormalities across most indicators. This was in contrast to the patients with a hospitalization duration of either less than or equal to 7 days or between 7 and 14 days. Furthermore, correlation analysis indicated that a longer duration of body temperature of ≥ 39°C, bilateral lung lobes infiltration detected by X ray, abnormal levels of AST, PaO2, and SPO2, and a lower age were all predictive of longer hospital stays. Furthermore, an elevated AST level and reduced liver synthesis capacity were related with a longer hospital stay and higher ADV copy number. Additionally, AST/ALT was correlated positively with IFN-γ level and IFN-γ level was only correlated positively with CD4+ T cells.

CONCLUSIONS

The study provided a set of predicting indicators for longer duration of hospitalization, which responded for primary severe ADV infection, and elucidated the possible reason for prolonged duration of hospitalization attributing to liver injury via higher ADV copy number, IFN-γ and CD4+ T cells, which suggested the importance of IFN-γ level and liver function monitoring for the patients with primary severe ADV infection.

Tonsillar cytotoxic CD4 T cells are involved in the control of EBV primary infection in children

CD4 T cells play a key role in Epstein Barr virus (EBV) infection, by modulating latent antigen expression, and exhibiting cytotoxic and regulatory properties. Our aim was to evaluate the presence of Granzyme B (GZMB) and Foxp3 CD4 T cells at different EBV infection status and latency profiles. We examined CD4, GZMB, Foxp3, IL10, TGF-β, CD4-GZMB and CD4-Foxp3 expression at the tonsils of pediatric patients with different infective status and EBV latency profiles. CD4+, GZMB+, Foxp3+, CD4-GZMB+ and CD4-Foxp3+ cell counts were higher at the interfollicular region. Higher expression of CD4-GZMB was found in primary infected patients compared to healthy carriers. In patients that expressed latency III antigens, we demonstrated lower CD4+, CD4-GZMB+, CD4-Foxp3+ expression; a negative correlation between the immunoregulatory cytokine IL-10+ and GZMB+ as well as a positive correlation of IL-10+ and CD4+. In patients expressing the lytic protein BMRF1, a positive correlation of TGF-β+ with CD4-GZMB+ and CD4-Foxp3+ was observed. Our findings indicate that CD4-GZMB+ cells are involved in the restriction of primary EBV infection in pediatric patients, which could partially explain the lack of symptoms, whereas both CD4-GZMB+ and CD4-Foxp3+ cells could be involved in the modulation of latency.

EBV Impact in Peripheral Macrophages' Polarization Cytokines in Pediatric Patients

Macrophages are exceptionally flexible cells. The presence of inflammatory cytokines such as IFN-γ and TNF-α results in an M1 (CD68) activation, while cytokines such as IL-10 or TGF-β induce the M2 (CD163) activation. Our aim was to study the behavior of peripheral cytokines involved in macrophage polarization and relate them with tissue findings to further comprehend the role of macrophages in EBV pediatric infection. We studied cytokine expression in tonsils and peripheral blood samples of children in different stages of infection. Peripheral cytokines were compared with macrophage polarization markers and viral protein expression in tonsils. Only IL-10 showed a negative correlation between compartments, exclusively in patients undergoing viral reactivation (R). Higher expressions of peripheral IL-1β, IL-23, and IL-12p40 in R children were observed. Lower expressions of local and peripheral TNF-α in patients with broader expressions of latent and lytic viral proteins were demonstrated. In healthy carrier (HC) patients, IL-23 positively correlated with CD163, and IP-10 positively correlated with CD68. Our results indicated that EBV might modulate antigen expression in the presence of TNF-α and influence peripheral cytokine expression differently in each stage of infection. Moreover, peripheral cytokines might have a particular role in macrophage polarization in HC.

Expression of EBV-encoded genes in children with asymptomatic infection detected by sensitive methods

Epstein-Barr virus (EBV) is an usually harmless virus whose oncogenic properties in vitro are related to its ability to transform lymphoid cells, and, in consequence, it can be associated with lymphomas. Since a few studies detected EBV presence in supposedly EBV-negative lymphomas, our aim was to evaluate EBV presence by sensitive gene expression assays in the tonsils from healthy pediatric donors from a region with high incidence of EBV-associated lymphomas. EBERs transcripts were detected by View RNA ISH in all cases, even in cases assessed negative by widely used in situ hybridization. The presence of LMP1 transcripts was proved in 93% of cases, co-expressed with EBNA2 in 30%. In this study, evidence for the expression of different latent and lytic viral genes in a population of young age of primary infection, detected with more sensitive methods, in particular at the germinal center, where most EBV-associated lymphomas originate, was provided.

Evidence for distinct mechanisms of immune suppression in EBV-positive and EBV-negative Hodgkin lymphoma

Epstein Barr Virus (EBV) has been recognized for its ability to transform B lymphocytes and for its association with different types of cancers including Hodgkin lymphoma. In addition, EBV may also modulate the microenvironment of HL. In this study, we aimed to investigate the prevalence of EBV among HL cases in Ethiopia and to assess the tissue cellular composition of EBV-related and EBV-unrelated cases. We constructed a tissue microarray (TMA) of 126 consecutive cases of classical HL (CHL) and nodular lymphocyte predominant HL (NLPHL) from a tertiary cancer centre, Tikur Anbessa Hospital, Addis Ababa, Ethiopia, and evaluated a panel of immunohistochemical markers. The quantification of immune cells was performed using HALO 2.3, a platform for image analysis from Indica Lab Inc. A total of 77/126 (61.1%) of HL cases expressed LMP1/EBER. Infiltration of CD8+, T-bet+ and FoxP3+ cells was higher in the microenvironment of EBV-related CHL, with P values of <0.001, <0.001 and <0.016, respectively. In contrast, the expression of PD1 was higher in the microenvironment of EBV-unrelated CHL cases (P < 0.001). Unlike in Western countries, the majority of HL cases in Ethiopia were associated with EBV. As FoxP3+ and PD1-expressing cells are thought to participate in down regulation of the immune response by different mechanisms, this finding highlights the previously unrecognized possibility that distinct immunosuppressive mechanisms may be ongoing within EBV positive and negative HL types. This may have important prognostic and therapeutic implications.

PD-L1 is upregulated in CD163+ tonsillar macrophages from children undergoing EBV primary infection

Epstein-Barr Virus (EBV) is a tumor associated virus that modulates not only the infected cells but also innate and adaptive immunity. Macrophages play a key role in tumor development and progression. Particularly, the M2 phenotype (CD163) with anti-inflammatory activity contributes to a favorable microenvironment for tumor development while the M1 (CD68) proinflammatory phenotype contributes to a restrictive one. In the context of pediatric EBV infection, little is known about macrophage contribution to PD-L1 expression, a molecule involved in immune exhaustion. We studied tonsils of primary infected (PI), healthy carriers (HC), reactivated (R), and not infected (NI) pediatric patients. Positive correlations were demonstrated for CD68+PD-L1+ in R and for CD163+PD-L1+ only in PI. Furthermore, CD163+PD-L1+ cell numbers were higher than PD-L1+CD68+ in PI patients. In addition, a positive correlation between PD-L1+CD163+ cells and LMP1 viral latent protein was observed in PI patients, and a positive correlation between PD-L1+CD68+ cells and BMRF1 lytic antigen was demonstrated. A positive correlation between TGF-β and PD-L1 expression was demonstrated in HC patients. Our findings indicate that EBV's lytic and latent antigens might be regulating macrophages' PD-L1 expression, particularly in PI patients, whereas, surprisingly, only TGF-β could be related to total PD-L1 upregulation. Given the relevance of macrophages and the PD-1/PD-L1 pathway in tumor progression and survival, more studies in early EBV infection could help to develop EBV-associated tumor therapies.

Epstein–Barr Virus (EBV) Genotypes Associated with the Immunopathological Profile of People Living with HIV-1: Immunological Aspects of Primary EBV Infection

Background: The aim of the present study was to evaluate the immunological profile of adult HIV-1+ patients coinfected with primary Epstein–Barr virus (EBV) infection who were free of antiretroviral drugs and inhabitants of the Brazilian Amazon region. Materials and methods: Primary EBV infection was screened by the semiquantitative detection of IgM and IgG anti-VCA. Genotypes were determined by conventional PCR. EBV and HIV viral load (VL) were quantified by real-time PCR. Cytokine dosage and cell quantification were performed by cytometry. Results: Only HIV-1+ individuals had primary EBV infection (7.12%). The EBV-1 genotype was the most prevalent (47.37%). The VL of HIV-1 was lower in the HIV/EBV-2 group. CD4+ T lymphocytes were inversely proportional to the VL of EBV in HIV/EBV-1/2 multi-infected patients. The HIV/EBV-2 group had the lowest cytokine levels, especially IFN-γ and IL-4. Different correlations were proposed for each coinfection. The late search for specific care related to HIV infection directly affected the cytokine profile and the number of CD8+ T lymphocytes. Symptoms were associated with the increase in VL of both viruses and cytokine profile. Conclusions: Different immunological profiles were associated with EBV genotypes in primary infection, with EBV-2 being more frequent in patients with low levels of HIV viral load. With late infection monitoring and consequent delay in the initiation of HAART, clinical changes and effects on the maintenance of the immune response were observed.

Seroprevalence of Epstein-Barr virus and cytomegalovirus infections in Presidente Figueiredo, Amazonas, Brazil

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections affect around 95% of the world's population. In Brazil, there are few epidemiological reports related to EBV and CMV infection, especially in the western Amazon region. This study aimed to estimate the seroprevalence of EBV and CMV infection in individuals residents in Presidente Figueiredo, Amazonas, Brazil. Blood samples of 443 individuals were tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. EBV (95.9%; 95% CI: 0.94;0.98), CMV (96.8%; 95% CI: 0.95;0.98) and CMV/EBV (93%;95% CI: 0.91-0.95) coinfection were highly prevalent in the study population. Children (1 to 5 years) not attending school were less susceptible to EBV (OR 0.15; 95% CI: 0.05-0.52; p = 0.017) and CMV infections (OR 0.05; 95% CI: 0.02 - 0.17; p < 0.0001). Teenagers at high school showed increased susceptibility to CMV infection (OR 4.65; 95%CI: 1.43-15.08; p = .013) and EBV/CMV co-infection (OR 3.04; 95%CI: 1.44-6.45; p = 0.005). The seroprevalence of CMV and EBV infections were preeminent and tend to increase with age in the study population. Either attendance to a daycare facility or primary school before the age of 5 years may increase the susceptibility to EBV or CMV infection.

"M1 macrophage polarization prevails in EBV infected children in an immuneregulatory environment"

Macrophages can be polarized toward a proinflammatory phenotype (M1) (CD68+) or to an anti-inflammatory one (M2) (CD163+). Polarization can be triggered by cytokines such as IFN-γ for M1, or IL-10 and TGF-β, for M2. In the context of pediatric EBV infection, little is known about macrophage polarization in EBV primary or persistent infection. When studying tonsils of patients undergoing primary infection (PI), healthy carrier (HC), reactivation (R) and not infected (NI), M1 profile prevailed in all infection status. However, an increase in M2 cells was observed in those patients with broader expression of latency antigens, in particular EBNA2. Tonsils from primary infected patients showed an increased IL-10 expression, whereas, unexpectedly, TGF-β expression correlated with M1 marker. Furthermore, an inverse correlation was demonstrated between CD68 and IFN-γ. Therefore, in the context of asymptomatic infection in children, M1 macrophage polarization prevails, even in the presence of IL-10 and TGF-ꞵ immunomodulatory cytokines, and it might be independent from lymphomagenesis process. Our finding indicates that macrophages may have a significant plasticity in response to different types of extrinsic stimuli, and further studies are required to investigate M1 polarization under anti-inflammatory stimuli. Importance Most studies on EBV primary infection have been performed in adolescents and young adult populations with Infectious Mononucleosis (IM) in developed countries. Furthermore, studies related to macrophage polarization were assessed in EBV-associated lymphomas, but little is known about macrophage polarization in the context of primary infection at the site of viral entry and replication, the tonsils. Therefore, the aim of this study was to characterize macrophage response in children undergoing EBV primary or persistent infection, in order to enlighten the role of macrophages in viral pathogenesis, in a population with a high incidence of EBV-associated lymphomas in children younger than 10 years old. This study may contribute to explain, at least in part, the asymptomatic viral infection in children from an underdeveloped region, since M1 polarization pattern prevails, but in a regulatory environment.

Epidemiological risk factors associated with primary infection by Epstein-Barr virus in HIV-1-positive subjects in the Brazilian Amazon region

To identify the prevalence and risk factors for primary Epstein–Barr virus (EBV) infection in human immunodeficiency virus (HIV)-1-positive adult treatment-naïve patients between January 2018 and December 2019 in a state of the Brazilian Amazon region. A total of 268 HIV-1 positive patients and 65 blood donors participated in the study. Epidemiological data were obtained from medical records and through a designed questionnaire. EBV infection was screened by the semiquantitative detection of anti-viral capsid antigen (VCA) EBV IgM and IgG, followed by molecular detection of the EBNA-3C gene. The plasma viral loads of HIV-1 and EBV were quantified using a commercial kit. The prevalence of primary coinfection was 7.12%. The associated risk factors were education level, family income, history of illicit drug use and sexually transmitted infections, homosexual contact and condom nonuse. Approximately 58.5% had late initiation of highly active antiretroviral therapy, which influenced the risk of HIV-EBV 1/2 multiple infection (odds ratio (OR): 4.76; 95% CI 1.51–15.04) and symptom development (p = 0.004). HIV viral load was associated with patient age (OR: 2.04; 95% CI 2.01–2.07; p = 0.026) and duration of illicit drug use (OR: 1.57; 95% CI 1.12–2.22; p = 0.0548). EBV viral load was associated with younger age (OR: 0.82; 95% CI 0.79–1.03; p = 0.0579). The replication of both viruses was associated with symptom development (HIV = OR: 2.06; 95% CI 1.22–3.50; p = 0.0073; EBV = OR: 8.81; 95% CI 1–10; p = 0.0447). The prevalence of HIV/EBV coinfection was lower than that observed in other studies, and social vulnerability and promiscuous sexual behavior were associated risk factors. A long time of HIV-1 infection, without therapy, influenced the risk of coinfection and disease progression. The viral loads of both viruses may be associated with some epidemiological aspects of the population.

Nasopharyngeal Carcinoma: The Role of the EGFR in Epstein-Barr Virus Infection

Epstein-Barr virus (EBV), a type 4 γ herpes virus, is recognized as a causative agent in nasopharyngeal carcinoma (NPC). Incidence of EBV-positive NPC have grown in recent decades along with worse outcomes compared with their EBV-negative counterparts. Latent membrane protein 1 (LMP1), encoded by EBV, induces NPC progression. The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases (RTK), is a driver of tumorigenesis, including for NPC. Little data exist on the relationship between EGFR and EBV-induced NPC. In our initial review, we found that LMP1 promoted the expression of EGFR in NPC in two main ways: the NF-κB pathway and STAT3 activation. On the other hand, EGFR also enhances EBV infection in NPC cells. Moreover, activation of EGFR signalling affects NPC cell proliferation, cell cycle progression, angiogenesis, invasion, and metastasis. Since EGFR promotes tumorigenesis and progression by downstream signalling pathways, causing poor outcomes in NPC patients, EGFR-targeted drugs could be considered a newly developed anti-tumor drug. Here, we summarize the major studies on EBV, EGFR, and LMP1-regulatory EGFR expression and nucleus location in NPC and discuss the clinical efficacy of EGFR-targeted agents in locally advanced NPC (LA NPC) and recurrent or metastatic NPC (R/M NPC) patients.

COVID-19 in Immunosuppressed Children

Following the spread of the SARS-CoV-2 infection and coronavirus disease 2019 (COVID-19) to a global pandemic, concerns have arisen for the disease impact in at-risk populations, especially in immunocompromised hosts. On the other hand, clinical studies have clarified that the COVID-19 clinical burden is mostly due to over-inflammation and immune-mediated multiorgan injury. This has led to downsizing the role of immunosuppression as a determinant of outcome, and early reports confirm the hypothesis that patients undergoing immunosuppressive treatments do not have an increased risk of severe COVID-19 with respect to the general population. Intriguingly, SARS-CoV-2 natural reservoirs, such as bats and mice, have evolved mechanisms of tolerance involving selection of genes optimizing viral clearance through interferon type I and III responses and also dampening inflammasome response and cytokine expression. Children exhibit resistance to COVID-19 severe manifestations, and age-related features in innate and adaptive response possibly explaining this difference are discussed. A competent recognition by the innate immune system and controlled pro-inflammatory signaling seem to be the pillars of an effective response and the premise for pathogen clearance in SARS-CoV-2 infection. Immunosuppression-if not associated with other elements of fragility-do not represent per se an obstacle to this competent/tolerant phenotype in children. Several reports confirm that children receiving immunosuppressive medications have similar clinical involvement and outcomes as the pediatric general population, indicating that maintenance treatments should not be interrupted in suspect or confirmed SARS-CoV-2 infection.

Neonatal and Children’s Immune System and COVID-19: Biased Immune Tolerance versus Resistance Strategy

The recent outbreak of COVID-19 has emerged as a major global health concern. Although susceptible to infection, recent evidence indicates mostly asymptomatic or mild presentation of the disease in infants, children, and adolescents. Similar observations were made for acute respiratory infections caused by other coronaviruses (severe acute respiratory syndrome and Middle East respiratory syndrome). These observations suggest that the immune system behaves differently in children than adults. Recent developments in the field demonstrated fundamental differences in the neonatal immune system as compared with adults, whereby infants respond to microorganisms through biased immune tolerance rather than resistance strategies. Similarly, more frequent/recent vaccinations in children and younger populations may result in trained immunity. Therefore, the physiological abundance of certain immunosuppressive cells, a tightly regulated immune system, and/or exposure to attenuated vaccines may enhance trained immunity to limit excessive immune reaction to COVID-19 in the young.