Clinical characteristics, outcome and the role of viral load in nontransplant patients with Epstein-Barr viraemia

A prospective evaluation of the diagnostic potential of EBV-DNA in plasma and whole blood

BACKGROUND

Quantitative polymerase chain reaction (qPCR) for Epstein-Barr virus (EBV)-DNA is an important diagnostic tool for EBV-associated disease, but interpretation of its clinical significance is challenging.

OBJECTIVES

We assessed the diagnostic and clinical performance of WHO-standardised qPCR for EBV-DNA (WHO EBV-qPCR) in plasma and whole blood (WB) for proven EBV disease in a prospectively accrued patient cohort.

STUDY DESIGN

Central Denmark Region patients, tested with WHO EBV-qPCR from November 2017 to March 2019, were screened for EBV disease. Incidence (IR) was estimated by Poisson regression. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were calculated for EBV-qPCR in plasma and WB. Risk of diagnostic latency was compared between patients with EBV-positive and EBV-negative lymphomas.

RESULTS

EBV disease was diagnosed in 95 of 1484 participants (IR: 16.3 per 1000 patientyears 95%CI; 13.3-19.9). Sensitivity and specificity of WHO EBV-qPCR in plasma was 82.4% (95% CI; 74.2-90.7%) and 87.8% (95% CI; 85.6-90%), yielding a PPV of 32.2% (95% CI; 24.9-39.5%) and NPV of 98.6% (95% CI; 97.7-99.5%) for proven EBV disease. Sensitivity and NPV were comparable in WB, while specificity and PPV decreased to 66.9% (95% CI; 60.6-73.1%) and 18.1% (95% CI; 7.5-28.7%). Risk of diagnostic latency was 2.3-fold (95% CI 1.4-4.1) higher for patients with EBV-positive compared with EBV-negative lymphomas.

CONCLUSIONS

WHO EBV-qPCR in plasma and WB have a low PPV but a high NPV for proven EBV disease. Implementation of WHO EBV-qPCR could improve interpretation and facilitate EBV-positive lymphoma diagnosis.

Clinical and Therapeutic Implications of Epstein-Barr Virus in HIV-Related Lymphomas

The incidence of lymphomas is increased in people living with HIV (PLWH). Aggressive B-cell non-Hodgkin lymphomas (NHLs) are the most common and are considered an AIDS-defining cancer (ADC). Although Hodgkin lymphoma (HL) is not considered an ADC, its incidence is also increased in PLWH. Among all HIV-related lymphomas (HRL), the prevalence of Epstein-Barr virus (EBV) is high. It has been shown that EBV is involved in different lymphomagenic mechanisms mediated by some of its proteins, contributing to the development of different lymphoma subtypes. Additionally, cooperation between both HIV and EBV can lead to the proliferation of aberrant B-cells, thereby being an additional lymphomagenic mechanism in EBV-associated HRL. Despite the close relationship between EBV and HRL, the impact of EBV on clinical aspects has not been extensively studied. These lymphomas are treated with the same therapeutic regimens as the general population in combination with cART. Nevertheless, new therapeutic strategies targeting EBV are promising for these lymphomas. In this article, the different types of HRL are extensively reviewed, focusing on the influence of EBV on the epidemiology, pathogenesis, clinical presentation, and pathological characteristics of each lymphoma subtype. Moreover, novel therapies targeting EBV and future strategies to treat HRL harboring EBV are discussed.

Plasma Epstein-Barr Virus Load as an Early Biomarker and Prognostic Factor of Human Immunodeficiency Virus-related Lymphomas

BACKGROUND

Epstein-Barr virus (EBV) has been implicated in lymphomagenesis and can be found infecting tumor cells and in plasma at lymphoma diagnosis, especially in human immunodeficiency virus (HIV)-infected patients. Our aim was to evaluate the usefulness of plasma EBV load as biomarker and prognostic factor in HIV-positive patients with lymphomas.

METHODS

EBV loads were measured by polymerase chain reaction in plasma samples of 81 HIV-positive patients' lymphomas at different moments: within 1 year before lymphoma diagnosis, at diagnosis, and at complete response (CR). Control samples included HIV-negative patients with lymphomas and HIV-positive patients without neoplasia or opportunistic infections.

RESULTS

HIV-positive patients with lymphomas had more frequently-detectable EBV load at lymphoma diagnosis (53%) than either HIV-negative patients with the same lymphoma type (16%; P < .001) or HIV-positive individuals without neoplasia or opportunistic infection (1.2%; P < .001). HIV-positive lymphoma patients with detectable EBV load in plasma at lymphoma diagnosis had statistically significant decrease of EBV load at CR. High EBV load (>5000 copies/mL) at lymphoma diagnosis was an independent negative prognostic factor for overall survival and progression-free survival in HIV-positive patients with lymphomas. Detectable plasma EBV loads identified HIV-positive subjects that would eventually develop lymphoma (area under the curve, 82%; 95% CI: 0.67-0.96).

CONCLUSIONS

Plasma EBV load can be used as a biomarker and as a prognostic factor in HIV-positive patients with lymphomas. The presence of the EBV load in the plasma of an HIV-positive patient can be an early predictor of lymphoma development.

Antibodies conjugated with viral antigens elicit a cytotoxic T cell response against primary CLL ex vivo

Chronic lymphocytic leukemia (CLL) is the most frequent B cell malignancy in Caucasian adults. The therapeutic armamentarium against this incurable disease has recently seen a tremendous expansion with the introduction of specific pathway inhibitors and innovative immunotherapy. However, none of these approaches is curative and devoid of side effects. We have used B-cell-specific antibodies conjugated with antigens (AgAbs) of the Epstein-Barr virus (EBV) to efficiently expand memory CD4⁺ cytotoxic T lymphocytes (CTLs) that recognized viral epitopes in 12 treatment-naive patients with CLL. The AgAbs carried fragments from the EBNA3C EBV protein that is recognized by the large majority of the population. All CLL cells pulsed with EBNA3C-AgAbs elicited EBV-specific T cell responses, although the intensity varied across the patient collective. Interestingly, a large proportion of the EBV-specific CD4⁺ T cells expressed granzyme B (GrB), perforin, and CD107a, and killed CLL cells loaded with EBV antigens with high efficiency in the large majority of patients. The encouraging results from this preclinical ex vivo study suggest that AgAbs have the potential to redirect immune responses toward CLL cells in a high percentage of patients in vivo and warrant the inception of clinical trials.

The clinical significance of EBV DNA in the plasma and peripheral blood mononuclear cells of patients with or without EBV diseases

Epstein-Barr virus (EBV) is a ubiquitous virus that establishes a latent infection within the host and in some cases can lead to the development of EBV-associated lymphomas, lymphoproliferative disorders, hemophagocytic lymphohistiocytosis, solid tumors, and other diseases. We studied the clinical significance of detecting EBV DNA in the plasma and peripheral blood mononuclear cells (PBMCs) of 2146 patients who had blood specimens sent to the Johns Hopkins Hospital clinical laboratory for viral quantitative real-time polymerase chain reaction assay over a 5-year period. Within this largely immunocompromised and hospitalized cohort, 535 patients (25%) had EBV detected in plasma or PBMCs. When EBV was detected in the absence of an EBV(+)disease (n = 402), it was present only in PBMCs in 69% of cases. Immunocompromised patients were less likely to have EBV in plasma than in PBMCs in the absence of EBV(+)disease. In patients with active, systemic EBV(+)diseases (n = 105), EBV was detected in plasma in 99% of cases but detected in PBMCs in only 54%. Across a range of copy number cutoffs, EBV in plasma had higher specificity and sensitivity for EBV(+)disease as compared with EBV in PBMCs. EBV copy number in plasma distinguished untreated, EBV(+)lymphoma from EBV(+)lymphoma in remission and EBV(-)lymphoma, and also distinguished untreated, EBV(+)posttransplantation lymphoproliferative disorder (PTLD) from EBV(+)PTLD in remission and EBV(-)PTLD. EBV copy number quantification is a useful diagnostic marker across the spectrum of EBV(+)diseases, even among immunocompromised patients, with plasma specimens more indicative of EBV(+)disease than PBMCs.

The Biology and Clinical Utility of EBV Monitoring in Blood

Epstein-Barr virus (EBV) DNA in blood can be quantified in peripheral blood mononuclear cells, in circulating cell-free (CCF) DNA specimens, or in whole blood. CCF viral DNA may be actively released or extruded from viable cells, packaged in virions or passively shed from cells during apoptosis or necrosis. In infectious mononucleosis, viral DNA is detected in each of these kinds of specimens, although it is only transiently detected in CCF specimens. In nasopharyngeal carcinoma, CCF EBV DNA is an established tumor marker. In EBV-associated Hodgkin lymphoma and in EBV-associated extranodal NK-/T-cell lymphoma, there is growing evidence for the utility of CCF DNA as a tumor marker.

Impact of Epstein-Barr virus load, virus genotype, and frequency of the 30 bp deletion in the viral BNLF-1 gene in patients harboring the human immunodeficiency virus

Patients infected with the human immunodeficiency virus (HIV) are at higher risk of developing Epstein-Barr Virus (EBV)-associated lymphomas. The usefulness of monitoring EBV in peripheral blood mononuclear cells (PBMCs) of patients infected with HIV has not been established. The aim of this study was to evaluate the EBV viral load in PBMCs, the frequency of viral genotypes, and the presence of the 30-bp deletion in the BNLF-1 gene. DNA samples from 156 patients attending the HIV/AIDS Day Clinic at Botucatu School of Medicine, Sao Paulo State University were evaluated. The EBV viral load was detectable by real time PCR in 123/156 (78.8%) cases and was higher in patients not receiving antiretroviral treatment or under therapeutic failure than in patients under successful highly active antiretroviral therapy (HAART) (P = 0.0076). Overall, the profile of patients with high EBV viral load included elevated HIV viremia (P = 0.0005), longer time of HIV diagnosis (P = 0.0026), and increased levels of T CD8 (+) lymphocytes (P = 0.0159). The successful amplification of the EBNA-2 gene by nested-PCR was achieved in 95 of 123 (77.2%) cases, of which 75.8% were EBV-1, 9.5% EBV-2, and 14.7% were co-infected with both EBV-1 and -2. The analysis of the BNLF-1 gene was possible in 99 of 123 (80.5%) cases, of which 50.5% had the 30-bp deletion. EBV-1 was more common than EBV-2, which may reflect the fact that the cohort was predominantly Caucasian and heterosexual.

Management of herpesvirus infections

Management of human herpesviruses remains a considerable clinical challenge, in part due to their ability to cause both lytic and latent disease. Infection with the Herpesviridae results in lifelong infection, which can reactivate at any time. Control of herpesviruses is by the innate and adaptive immune systems. Herpesviruses must evade the host innate immune system to establish infection. Once infected, the adaptive immune response, primarily CD8(+) T-cells, is crucial in establishing and maintaining latency. Latent herpesviruses are characterised by the presence of viral DNA in infected cells and limited or no viral replication. These characteristics provide a challenge to clinicians and those developing antiviral agents. The scope of this review is two-fold. First, to provide an overview of all antivirals used against herpesviruses, including their mechanism of action, pharmacokinetics, side effects, resistance and clinical uses. And second, to address the management of each of the eight herpesviruses both in the immunocompetent and immunocompromised host, providing evidence for clinical management and therapeutic options, which is important to the clinician engaged in the management of these infections.