Dynamics of Epstein-Barr Virus (EBV) in human immunodeficiency virus (HIV)-1 infected adults and children

Epstein-Barr Virus (EBV) is involved in a wide range of malignancies, particularly in immunocompromised subjects. Besides immunodepression, chronic immune activation may induce B-cell stimulation leading to an expansion of EBV-infected cells, thus increasing the risk of EBV-related malignancies. The factors that may contribute to HIV-1-induced B cell activation and expansion of EBV-infected cells are largely unknown. In Africa EBV primary infection occurs during infancy and early childhood and EBV-associated lymphomas represent an important cause of morbidity and mortality in children. High levels of EBV represent a risk factor for the onset of EBV-related malignancies. To date, no data are available about EBV-infection and related malignancies in the context of HIV-1 infection in African children; this may be partly due to lack of access of laboratory analyses in developing countries. The use of Dried Blood Spot (DBS) may represent an easy method to collect and store blood samples and allow their reliable transport to specialized laboratories. My PhD research focused on the following themes: 1) the relationship between markers of immune activation and EBV load in HIV-1 infected patients. 2) EBV infection in HIV-1 infected and uninfected children in African countries. 3) a new application of Dried Blood Spot to type and quantify EBV and to identify B cell clonality in order to diagnose and monitor B-cell malignancies. 1) EBV load and immune activation in HIV-1-infected patients A total of 156 HIV-1-infected patients were included in this study, 85 of which were under antiretroviral therapy (ART). EBV-DNA was detected in 114 patients, and in all but 3 it was EBV type 1. The median [interquartile] EBV-DNA load was 43[1-151] copies/105 cells and it was higher in patients with detectable HIV-1 plasma viremia, despite good immunological status (CD4>500 cells/µl), than in patients with undetectable HIV-1 plasma viremia regardless of immunological status (46[5-136] vs 17[1-56] copies/105 cells, p=0.008). Patients with high EBV-DNA load (>median value) presented higher levels of LPS and proinflammatory cytokines (IL-6, IL-10 and TNF-α) than patients with low EBV load. Furthermore, percentages of activated B-cells correlated with EBV-DNA load (r=0.754; p<0.001). Overall, these findings indicate a strong association between HIV-1 viremia, markers of immune activation and EBV load, and suggest that persistence of HIV-1 viremia and immune activation, regardless of peripheral CD4 cell depletion/repopulation, may favour the expansion of EBV-infected cells. 2) Association between NHL and blood levels of EBV in children in Tanzania, and dynamics of EBV in HIV-1-infected children in Uganda A matched case-control study was performed in children with Non-Hodgkin’s Lymphoma (NHL) admitted to three clinical centers in Tanzania, and their age-matched controls. Blood samples were collected on DBS. 21 out of 35 (60%) NHL patients and only 21 out of 70 (30%) controls presented EBV detectable in peripheral blood, thus showing a significant association between NHL and EBV in blood (OR=4.77 [95% CI 1.71–13.33], p=0.003). Furthermore, EBV-DNA levels were higher in cases compared to EBV-positive controls (p=0.024). Overall, these findings indicate that EBV-DNA load in peripheral blood might have diagnostic relevance. In a second study, blood samples from 213 HIV-1-infected children were collected on DBS at the Nsambya Home Care, Kampala, Uganda. 92 out of 140 (66%) children on ART and 57 out of 73 (78%) ART-naive children were found to be EBV-positive. After adjusting for CD4 Z-score, age and WHO stage, children on ART presented less odds of having detectable EBV than ART-naive children (OR=0.39 [95% CI 0.16-0.94], p=0.036). EBV load was significantly higher in ART-naive children than those on ART (4.22 [3.87-4.58] vs 3.99 [3.55-4.33] log10 copies/ml; p=0.016). Levels of 16S rDNA, a marker of microbial translocation, were significantly higher in ART-naive children than those on ART (2.16 [2.11-2.28] vs 2.09 [2.02-2.22] log10 copies/μl; p=0.007) and correlated with EBV-DNA levels (r=0.382, p=0.016), suggesting that circulating microbial products lead to B cell activation and expansion of EBV-infected B cells. Treatment with ART, likely by limiting HIV-1 load and thus the HIV-1-driven immune activation, may restrict EBV replication and expansion of EBV-infected cells. 3) Detection of clonal B-cell populations from DBS sampling: a tool for the diagnosis and monitoring of B-cell malignancies Firstly, through blood samples from donors, we ensured that DBS contains sufficient lymphocytes to perform a clonality assay without yielding false positive results. Using Namalwa cells that contain 2 EBV copies/cell, we found a good relationship between the expected and detected EBV-DNA copies (r=0.987, p<0.0001) and we established that a clonal B-cell population on DBS was detected when there were at least 200 clonal cells in the analysed sample. Moreover, very similar clonal results were obtained between DNA from DBS and fresh whole blood from patients with chronic lymphocytic leukemia. This study demonstrated the possibility to perform clonality testing on DBS sampling, thus improving the diagnostic and monitoring options. Conclusions In these studies, we found a significant relationship between markers of microbial translocation, levels of pro-inflammatory cytokines and EBV-DNA levels in both HIV-1 infected adults and children, suggesting that cell activation driven by HIV-1 antigens may result in chronic B cell stimulation and expansion of EBV-infected B cells, a risk factor for the development of EBV-related malignancies. Of interest, we found that EBV-DNA levels were higher in patients with a gain in CD4 lymphocytes, but incomplete suppression of HIV-1 viremia than in patients with undetectable plasma viremia, regardless their CD4 cell number. The relationship between immune activation and EBV levels was also supported by the findings in HIV-1 infected children in Uganda. Moreover, we found that EBV-DNA and 16S rDNA levels were significantly lower in children on ART than in those ART-naive, suggesting that treatment with ART, likely by limiting immune activation, may prevent B cell stimulation and expansion of EBV-infected B cells. These observations may become particularly interesting to plan future therapeutic strategies in HIV-1 infected patients. We also found that NHLs are strongly associated with EBV load in peripheral blood, suggesting that high levels of EBV in blood might have diagnostic and prognostic relevance for the diagnosis and monitoring of EBV-related B cell malignancies. In this context we assessed that DBS sampling was also suitable to identify the presence of a B cell clonal population. Our results showed it is possible to perform clonality testing on DBS sampling, thereby improving the diagnostic and monitoring capability of B cell lymphomas in resource-limited settings

Extra-telomeric functions of telomerase in the pathogenesis of Epstein-Barr virus-driven B-cell malignancies and potential therapeutic implications

Abstract The Epstein-Barr virus (EBV) is a ubiquitous human \u3b3-herpesvirus causally linked to a broad spectrum of both lymphoid and epithelial malignancies. In order to maintain its persistence in host cells and promote tumorigenesis, EBV must restrict its lytic cycle, which would ultimately lead to cell death, selectively express latent viral proteins, and establish an unlimited proliferative potential. The latter step depends on the maintenance of telomere length provided by telomerase. The viral oncoprotein LMP-1 activates TERT, the catalytic component of telomerase. In addition to its canonical role in stabilizing telomeres, TERT may promote EBV-driven tumorigenesis through extra-telomeric functions. TERT contributes toward preserving EBV latency; in fact, through the NOTCH2/BATF pathway, TERT negatively affects the expression of BZLF1, the master regulator of the EBV lytic cycle. In contrast, TERT inhibition triggers a complete EBV lytic cycle, leading to the death of EBV-infected cells. Interestingly, short-term TERT inhibition causes cell cycle arrest and apoptosis, partly by inducing telomere-independent activation of the ATM/ATR/TP53 pathway. Importantly, TERT inhibition also sensitizes EBV-positive tumor cells to antiviral therapy and enhances the pro-apoptotic effects of chemotherapeutic agents. We provide here an overview on how the extra-telomeric functions of TERT contribute to EBV-driven tumorigenesis. We also discuss the potential therapeutic approach of TERT inhibition in EBV-driven malignancies

Accelerated aging in perinatally HIV-infected children: clinical manifestations and pathogenetic mechanisms

BACKGROUND: Premature aging and related diseases have been documented in HIV-infected adults. Data are now emerging also regarding accelerated aging process in HIV-infected children. METHODS: A narrative review was performed searching studies on PubMed published in English language in 2004-2017, using appropriate key words, including "aging", "children", "HIV", "AIDS", "immunosenescence", "pathogenesis", "clinical conditions". RESULTS: Premature immunosenescence phenotype of B and T cells in HIV-infected children is mediated through immune system activation and chronic inflammation. Ongoing inflammation processes have been documented by increased levels of pathogen-associated molecular patterns (PAMPS), increased mitochondrial damage, higher levels of pro-inflammatory cytokines, and a positive correlation between sCD14 levels and percentages of activated CD8+ cells. Other reported features of premature aging include cellular replicative senescence, linked to an accelerated telomeres shortening. Finally, acceleration of age-associated methylation pattern and other epigenetic modifications have been described in HIV-infected children. All these features may favor the clinical manifestations related to premature aging. Lipid and bone metabolism, cancers, cardiovascular, renal, and neurological systems should be carefully monitored, particularly in children with detectable viremia and/or with CD4/CD8 ratio inversion. CONCLUSION: Aging processes in children with HIV infection impact their quality and length of life. Further studies regarding the mechanisms involved in premature aging are needed to search for potential targets of treatment

Impact of monotherapy on HIV-1 reservoir, immune activation, and co-infection with Epstein-Barr virus

Abstract Objectives Although monotherapy (mART) effectiveness in maintaining viral suppression and CD4 cell count has been extensively examined in HIV-1-infected patients, its impact on HIV-1 reservoir, immune activation, microbial translocation and co-infection with Epstein-Barr Virus (EBV) is unclear. Methods This retrospective study involved 32 patients who switched to mART; patients were studied at baseline, 48 and 96 weeks after mART initiation. Thirty-two patients who continued combined antiretroviral therapy (cART) over the same period of time were included in the study. Markers of HIV-1 reservoir (HIV-1 DNA and intracellular HIV-1 RNA) were quantified by real-time PCR. Markers of T-(CD3(+)CD8(+)CD38(+)) and B-(CD19(+)CD80/86(+) and CD19(+)CD10-CD21(low)CD27(+)) cell activation were evaluated by flow cytometry. Plasma levels of microbial translocation markers were quantified by real-time PCR (16S ribosomal DNA and mitochondrial [mt] DNA) or by ELISA (LPS and sCD14). EBV was typed and quantified by multiplex real-time PCR. Results At baseline, no differences were found between mART and cART groups. Three (10%) mART-treated patients had a virological failure vs none in the cART group. Levels of HIV-1 DNA, intracellular HIV-1 RNA and EBV-DNA remained stable in the mART group, while decreased significantly in the cART group. Percentages of T-and B-activated cells significantly increased in the mART-treated patients, while remained at low levels in the cART-treated ones (p = 0.014 and p<0.001, respectively). Notably, levels of mtDNA remained stable in the cART group, but significantly rose in the mART one (p<0.001). Conclusions Long-term mART is associated with higher levels of T-and B-cell activation and, conversely to cART, does not reduce the size of HIV-1 reservoir and EBV co-infection

Pediatric Human Immunodeficiency Virus infection and cancer in the Highly Active Antiretroviral Treatment (HAART) era

Abstract Highly active antiretroviral therapy (HAART) changed the natural history of pediatric HIV infection. This review focuses on trends of HIV-associated cancers in childhood in the HAART era and analyses potential pathogenetic mechanisms. HAART reduced AIDS-defined-malignancies (ADM), but incidence of several non-ADM is increasing. HIV-associated immune activation and inflammation, promoting tumorigenesis, can only partially be reduced by HAART. In addition, HIV-infected children may undergo accelerated immune senescence that favors cancer development. How HAART affects this condition is an open question. Lastly, there is no evidence that prenatal exposure to HAART increases the risk of cancer in childhood, but long-term studies are needed

Premature aging and immune senescence in HIV-infected children

Objective: Several pieces of evidence indicate that HIV-infected adults undergo premature aging. The effect of HIV and antiretroviral therapy (ART) exposure on the aging process of HIV-infected children may be more deleterious since their immune system coevolves from birth with HIV. Design: Seventy-one HIV-infected (HIV+), 65 HIV-exposed-uninfected (HEU), and 56 HIV-unexposed-uninfected (HUU) children, all aged 0\u20135 years, were studied for biological aging and immune senescence. Methods: Telomere length and T-cell receptor rearrangement excision circle levels were quantified in peripheral blood cells by real-time PCR. CD4+ and CD8+ cells were analysed for differentiation, senescence, and activation/exhaustion markers by flow cytometry. Results: Telomere lengths were significantly shorter in HIV+ than in HEU and HUU children (overall, P < 0.001 adjusted for age); HIV+ ART-naive (42%) children had shorter telomere length compared with children on ART (P = 0.003 adjusted for age). T-cell receptor rearrangement excision circle levels and CD8+ recent thymic emigrant cells (CD45RA+CD31+) were significantly lower in the HIV+ than in control groups (overall, P = 0.025 and P = 0.005, respectively). Percentages of senescent (CD28-CD57+), activated (CD38+HLA-DR+), and exhausted (PD1+) CD8+ cells were significantly higher in HIV+ than in HEU and HUU children (P = 0.004, P < 0.001, and P < 0.001, respectively). Within the CD4+ cell subset, the percentage of senescent cells did not differ between HIV+ and controls, but programmed cell death receptor-1 expression was upregulated in the former. Conclusions: HIV-infected children exhibit premature biological aging with accelerated immune senescence, which particularly affects the CD8+ cell subset. HIV infection per se seems to influence the aging process, rather than exposure to ART for prophylaxis or treatmen

Premature aging and immune senescence in HIV-infected children.

Objective: Several pieces of evidence indicate that HIV-infected adults undergo premature aging. The effect of HIV and antiretroviral therapy (ART) exposure on the aging process of HIV-infected children may be more deleterious since their immune system coevolves from birth with HIV. Design: Seventy-one HIV-infected (HIV+), 65 HIV-exposed-uninfected (HEU), and 56 HIV-unexposed-uninfected (HUU) children, all aged 0-5 years, were studied for biological aging and immune senescence. Methods: Telomere length and T-cell receptor rearrangement excision circle levels were quantified in peripheral blood cells by real-time PCR. CD4+ and CD8+ cells were analysed for differentiation, senescence, and activation/exhaustion markers by flow cytometry. Results: Telomere lengths were significantly shorter in HIV+ than in HEU and HUU children (overall, P < 0.001 adjusted for age); HIV+ ART-naive (42%) children had shorter telomere length compared with children on ART (P = 0.003 adjusted for age). T-cell receptor rearrangement excision circle levels and CD8+ recent thymic emigrant cells (CD45RA+CD31+) were significantly lower in the HIV+ than in control groups (overall, P = 0.025 and P = 0.005, respectively). Percentages of senescent (CD28−CD57+), activated (CD38+HLA-DR+), and exhausted (PD1+) CD8+ cells were significantly higher in HIV+ than in HEU and HUU children (P = 0.004, P < 0.001, and P < 0.001, respectively). Within the CD4+ cell subset, the percentage of senescent cells did not differ between HIV+ and controls, but programmed cell death receptor-1 expression was upregulated in the former. Conclusions: HIV-infected children exhibit premature biological aging with accelerated immune senescence, which particularly affects the CD8+ cell subset. HIV infection per se seems to influence the aging process, rather than exposure to ART for prophylaxis or treatment. Keywords: immune activation, immune senescence, microbial translocation, pediatric HIV/AIDS, premature aging, telomere length, T-cell receptor rearrangement excision circl

Immune activation, immune senescence and levels of Epstein Barr Virus in kidney transplant patients: Impact of mTOR inhibitors

Abstract Post-transplant lymphoproliferative disorders (PTLD) represent a severe complication in transplanted patients and Epstein-Barr Virus (EBV) is the main driver. Besides immunodepression, immune activation/chronic inflammation play an important role in both virus reactivation and expansion of EBV-positive B cells. The aim of this study was to assess the impact of immunosuppressive strategies on factors involved in the PTLD's pathogenesis. 124 kidney transplanted patients were enrolled in this study: 71 were treated with mycophenolic acid (MPA) and 53 treated with mTOR inhibitor (mTORi), both in combination with different doses of calcineurin inhibitor. At the time of the transplant (T0), profile of inflammation/immune activation and immune senescence didn't differ between the two groups, but after one year of treatment (T1) markers were significantly higher in MPA-treated patients; their immunosenescence process was supported by the greater erosion of telomeres despite their younger age. Percentages of activated B cells and levels of EBV-DNA significantly increased in MPA-treated patients, and at T1 were significantly higher in MPA- than in mTORi-treated patients. Overall, these findings indicate that mTOR inhibitors constrain the inflammation/immune activation and senescence status, thus reducing the expansion of EBV-infected B cells and the risk of virus-associated PTLD in kidney transplant recipients

Relationship Between Non-Hodgkin's Lymphoma and Blood Levels of Epstein-Barr Virus in Children in North-Western Tanzania: A Case Control Study.

Non-Hodgkin's Lymphomas (NHL) are common in African children, with endemic Burkitt's lymphoma (BL) being the most common subtype. While the role of Epstein-Barr Virus (EBV) in endemic BL is known, no data are available about clinical presentations of NHL subtypes and their relationship to Human Immunodeficiency Virus (HIV) infection and Epstein Barr Virus (EBV) load in peripheral blood of children in north-western, Tanzania. A matched case control study of NHL subtypes was performed in children under 15 years of age and their respective controls admitted to Bugando Medical Centre, Sengerema and Shirati district designated hospitals in north-western, Tanzania, between September 2010 and April 2011. Peripheral blood samples were collected on Whatman 903 filter papers and EBV DNA levels were estimated by multiplex real-time PCR. Clinical and laboratory data were collected using a structured data collection tool and analysed using chi-square, Fisher and Wilcoxon rank sum tests where appropriate. The association between NHL and detection of EBV in peripheral blood was assessed using conditional logistic regression model and presented as odds ratios (OR) and 95% confidence intervals (CI). A total of 35 NHL cases and 70 controls matched for age and sex were enrolled. Of NHLs, 32 had BL with equal distribution between jaw and abdominal tumour, 2 had large B cell lymphoma (DLBCL) and 1 had NHL-not otherwise specified (NHL-NOS). Central nervous system (CNS) presentation occurred only in 1 BL patient; 19 NHLs had stage I and II of disease. Only 1 NHL was found to be HIV-seropositive. Twenty-one of 35 (60%) NHL and 21 of 70 (30%) controls had detectable EBV in peripheral blood (OR = 4.77, 95% CI 1.71 - 13.33, p = 0.003). In addition, levels of EBV in blood were significantly higher in NHL cases than in controls (p = 0.024). BL is the most common childhood NHL subtype in north-western Tanzania. NHLs are not associated with HIV infection, but are strongly associated with EBV load in peripheral blood. The findings suggest that high levels of EBV in blood might have diagnostic and prognostic relevance in African children

Virological and immunological features of SARS-CoV-2-infected children who develop neutralizing antibodies

As the global COVID-19 pandemic progresses, it is paramount to gain knowledge on adaptive immunity to SARS-CoV-2 in children to define immune correlates of protection upon immunization or infection. We analyzed anti-SARS-CoV-2 antibodies and their neutralizing activity (PRNT) in 66 COVID-19-infected children at 7 (\ub12) days after symptom onset. Individuals with specific humoral responses presented faster virus clearance and lower viral load associated with a reduced in&nbsp;vitro infectivity. We demonstrated that the frequencies of SARS-CoV-2-specific CD4+CD40L+ T&nbsp;cells and Spike-specific B cells were associated with the anti-SARS-CoV-2 antibodies and the magnitude of neutralizing activity. The plasma proteome confirmed the association between cellular and humoral SARS-CoV-2 immunity, and PRNT+ patients show higher viral signal transduction molecules (SLAMF1, CD244, CLEC4G). This work sheds lights on cellular and humoral anti-SARS-CoV-2 responses in children, which may drive future vaccination trial endpoints and quarantine measures policies