Patients at risk for development of posttransplant lymphoproliferative disorder: plasma versus peripheral blood mononuclear cells as material for quantification of Epstein-Barr viral load by using real-time quantitative polymerase chain reaction

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

Screening and Management of PTLD

Posttransplant lymphoproliferative disorder (PTLD) represents a heterogeneous group of lymphoproliferative diseases occurring in the setting of immunosuppression following hematopoietic stem cells transplant and solid organ transplantation. Despite its overall low incidence, PTLD is a serious complication following transplantation, with a mortality rate as high as 50% in transplant recipients. Therefore, it is important to establish for each transplant recipient a personalized risk evaluation for the development of PTLD based on the determination of Epstein-Barr virus serostatus and viral load following the initiation of immunosuppression. Due to the dynamic progression of PTLD, reflected in the diverse pathological features, different therapeutic approaches have been used to treat this disorder. Moreover, new therapeutic strategies based on the administration of virus-specific cytotoxic T cells have been developed. In this review, we summarize the available data on screening and treatment to suggest a strategy to identify transplant recipients at a higher risk for PTLD development and to review the current therapeutic options for PTLD.

Characteristics and Outcome of Post-Transplant Lymphoproliferative Disorders After Solid Organ Transplantation: A Single Center Experience of 196 Patients Over 30 Years

Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication after transplantation. In this retrospective, monocentric study we aimed to collect real life data regarding PTLD and determine the role of Epstein Barr Virus (EBV) status and year of diagnosis on prognosis. We identified 196 biopsy-proven PTLD after solid organ transplantation (SOT) diagnosed at the University Hospitals Leuven (Belgium) from 1989 to 2019. EBV status was positive in 61% of PTLD. The median overall survival (OS) was 5.7 years (95% CI: 2.99-11.1). Although EBV positivity was not significantly correlated with OS in multivariate analyses (HR: 1.44 (95% CI: 0.93-2.24); p = 0.10), subgroup analysis showed a significantly better median OS for EBV negative post-transplant diffuse large B-cell lymphoma (DLBCL) compared to EBV positive post-transplant DLBCL (8.8 versus 2.5 years respectively; p = 0.0365). There was a significant relation between year of PTLD diagnosis and OS: the more recent the PTLD diagnosis, the lower the risk for death (adjusted HR: 0.962 (95% CI: 0.931-0.933); p = 0.017). In conclusion, the prognosis of PTLD after SOT has improved in the past decades. Our analysis shows a significant relation between EBV status and OS in post-transplant DLBCL.

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.

EBV-associated diseases: Current therapeutics and emerging technologies

EBV is a prevalent virus, infecting >90% of the world's population. This is an oncogenic virus that causes ~200,000 cancer-related deaths annually. It is, in addition, a significant contributor to the burden of autoimmune diseases. Thus, EBV represents a significant public health burden. Upon infection, EBV remains dormant in host cells for long periods of time. However, the presence or episodic reactivation of the virus increases the risk of transforming healthy cells to malignant cells that routinely escape host immune surveillance or of producing pathogenic autoantibodies. Cancers caused by EBV display distinct molecular behaviors compared to those of the same tissue type that are not caused by EBV, presenting opportunities for targeted treatments. Despite some encouraging results from exploration of vaccines, antiviral agents and immune- and cell-based treatments, the efficacy and safety of most therapeutics remain unclear. Here, we provide an up-to-date review focusing on underlying immune and environmental mechanisms, current therapeutics and vaccines, animal models and emerging technologies to study EBV-associated diseases that may help provide insights for the development of novel effective treatments.

Epstein-Barr virus DNA loads in the peripheral blood cells predict the survival of locoregionally-advanced nasopharyngeal carcinoma patients

OBJECTIVE

Circulating cell-free Epstein-Barr virus (EBV) DNA has been shown to be a valuable biomarker for population screening and prognostic surveillance for nasopharyngeal carcinoma (NPC). Despite important insights into the biology of persistence, few studies have addressed the clinical significance of cell-based EBV-DNA loads in peripheral blood cells (PBCs).

METHODS

A prospective observational cohort study was conducted involving 1,063 newly diagnosed, locoregionally-advanced NPC patients at Sun Yat-sen University Cancer Center from 2005 to 2007. Cox regression analysis was conducted to identify the association of PBC EBV DNA loads to overall survival (OS) and other prognostic outcomes. Prognostic nomograms were developed based on PBC EBV DNA loads to predict survival outcomes for NPC patients.

RESULTS

After a median follow-up of 108 months, patients with higher PBC EBV-DNA loads had significantly worse OS [hazard ratio (HR) of medium, medium-high, and high vs. low were 1.50, 1.52, and 1.85 respectively; Ptrend < 0.001]. Similar results were found for progression-free survival and distant metastasis-free survival. The concordance index of the prognostic nomogram for predicting OS in the training set and validation set were 0.70 and 0.66, respectively. Our data showed that the PBC EBV DNA load was an independent and robust survival biomarker, which remained significant even after adjusting for plasma EBV DNA loads in a subset of 205 patients of the cohort (HR: 1.88; P = 0.025). Importantly, a combination of PBC EBV DNA load and plasma EBV DNA load improved the predicted OS.

CONCLUSIONS

The EBV-DNA load in PBCs may be an independent prognosis marker for NPC patients.

Analysis of Post-Transplant Lymphoproliferative Disorder (PTLD) Outcomes with Epstein-Barr Virus (EBV) Assessments-A Single Tertiary Referral Center Experience and Review of Literature

Post-transplant lymphoproliferative disorders (PTLDs) are lymphoid or plasmacytic proliferations ranging from polyclonal reactive proliferations to overt lymphomas that develop as consequence of immunosuppression in recipients of solid organ transplantation (SOT) or allogeneic bone marrow/hematopoietic stem cell transplantation. Immunosuppression and Epstein-Barr virus (EBV) infection are known risk factors for PTLD. Patients with documented histopathologic diagnosis of primary PTLD at our institution between January 2000 and October 2019 were studied. Sixty-six patients with PTLD following SOT were followed for a median of 9.0 years. The overall median time from transplant to PTLD diagnosis was 5.5 years, with infant transplants showing the longest time to diagnosis at 12.0 years, compared to pediatric and adolescent transplants at 4.0 years and adult transplants at 4.5 years. The median overall survival (OS) was 19.0 years. In the monomorphic diffuse large B-cell (M-DLBCL-PTLD) subtype, median OS was 10.7 years, while median OS for polymorphic subtype was not yet reached. There was no significant difference in OS in patients with M-DLBCL-PTLD stratified by quantitative EBV viral load over and under 100,000 copies/mL at time of diagnosis, although there was a trend towards worse prognosis in those with higher copies.

Pathobiology and treatment of lymphomatoid granulomatosis, a rare EBV-driven disorder

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus (EBV)-driven B-cell lymphoproliferative disease (LPD). This disease is hypothesized to result from defective immune surveillance of EBV, with most patients showing evidence of immune dysfunction, despite no known primary immunodeficiency. Pathologically, LYG is graded by the number and density of EBV+ atypical B cells, and other characteristic findings include an angioinvasive/angiodestructive reactive T-cell infiltrate and various degrees of necrosis. Clinically, LYG universally involves the lungs with other common extranodal sites, including skin, central nervous system, liver, and kidneys. Nodal and/or bone marrow involvement is extremely rare and, if present, suggests an alternative diagnosis. Treatment selection is based on histologic grade and underlying pathobiology with low-grade disease hypothesized to be immune-dependent and typically polyclonal and high-grade disease to be immune-independent and typically oligoclonal or monoclonal. Methods of augmenting the immune response to EBV in low-grade LYG include treatment with interferon-α2b, whereas high-grade disease requires immunochemotherapy. Given the underlying defective immune surveillance of EBV, patients with high-grade disease may have a recurrence in the form of low-grade disease after immunochemotherapy, and those with low-grade disease may progress to high-grade disease after immune modulation, which can be effectively managed with crossover treatment. In patients with primary refractory disease or in those with multiple relapses, hematopoietic stem cell transplantation may be considered, but its efficacy is not well established. This review discusses the pathogenesis of LYG and highlights distinct histopathologic and clinical features that distinguish this disorder from other EBV+ B-cell LPDs and lymphomas. Treatment options, including immune modulation and combination immunochemotherapy, are discussed.

Tenofovir prodrugs potently inhibit Epstein-Barr virus lytic DNA replication by targeting the viral DNA polymerase

Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus that establishes life-long infection and increases the risk for the development of several cancers and autoimmune diseases. The mechanisms by which chronic EBV infection leads to subsequent disease remain incompletely understood. Lytic reactivation plays a central role in the development of EBV-driven cancers and may contribute to other EBV-associated diseases. Thus, the clinical use of antivirals as suppressive therapy for EBV lytic reactivation may aid efforts aimed at disease prevention. Current antivirals for EBV have shown limited clinical utility due to low potency or high toxicity, leaving open the need for potent antivirals suitable for long-term prophylaxis. In the present study, we show that tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), drugs with excellent safety profiles used clinically for HIV prevention, inhibit EBV lytic DNA replication, with respective IC₅₀ values of 0.30 μM and 84 nM. In a cell-based assay, TAF was 35- and 24-fold and TDF was 10- and 7-fold more potent than acyclovir and penciclovir, respectively, and TAF was also twice as potent as ganciclovir. The active metabolite of tenofovir prodrugs, tenofovir-diphosphate, inhibited the incorporation of dATP into a primed DNA template by the EBV DNA polymerase in vitro. In contrast to acyclovir, treatment of cells during latency for 24 h with TAF still inhibited EBV lytic DNA replication at 72 h after drug was removed. Our results suggest that tenofovir prodrugs may be particularly effective as inhibitors of EBV lytic reactivation, and that clinical studies to address critical questions about disease prevention are warranted.

Epstein-Barr virus related post-transplant lymphoproliferative disorder prevention strategies in allogeneic hematopoietic stem cell transplantation

Epstein-Barr virus associated post-transplant lymphoproliferative disorders (EBV PTLD) are recognized as a significant cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT). The number of patients at risk of developing EBV PTLD is increasing, partly as a result of highly immunosuppressive regimens, including the use of anti-thymocyte globulin (ATG). Importantly, there is heterogeneity in PTLD management strategies between alloHSCT centers worldwide. This review summarizes the different EBV PTLD prevention strategies being utilized including the alloHSCT and T-cell depletion regimes and the risk they confer; monitoring programs, including the timing and analytes used for EBV virus detection, as well as pre-emptive thresholds and therapy with rituximab. In the absence of an institution-specific policy, it is suggested that the optimal pre-emptive strategy in HSCT recipients with T-cell depleting treatments, acute graft vs host disease (GVHD) and a mismatched donor for PTLD prevention is (a) monitoring of EBV DNA post-transplant weekly using plasma or WB as analyte and (b) pre-emptively reducing immune suppression (if possible) at an EBV DNA threshold of >1000 copies/mL (plasma or WB), and treating with rituximab at a threshold of >1000 copies/mL (plasma) or >5000 copies/mL (WB). There is emerging evidence for prophylactic rituximab as a feasible and safe strategy for PTLD, particularly if pre-emptive monitoring is problematic. Future management strategies such as prophylactic EBV specific CTLs have shown promising results and as this procedure becomes less expensive and more accessible, it may become the strategy of choice for EBV PTLD prevention.

Infection prophylaxis and management of viral infection

Viral infections are associated with significant morbidity and mortality in lung transplant recipients. Importantly, several viral infections have been associated with the development of chronic lung allograft dysfunction (CLAD). Community-acquired respiratory viruses (CARV) such as influenza and respiratory syncytial virus (RSV), are frequently associated with acute and chronic rejection. Cytomegalovirus (CMV) remains a significant burden in regards to morbidity and mortality in lung transplant recipients. Epstein-Barr virus (EBV) is mostly involved with the development of post-transplant lymphoproliferative disorder (PTLD), a lymphoid proliferation that occurs in the setting of immunosuppression. On the other hand, the development of direct acting antivirals for hepatitis C virus (HCV) is changing the use of HCV-positive organs in transplantation. In this article we will focus on reviewing common viral infections that have a significant impact on lung transplant recipients looking at epidemiology, prevention and potential treatment.

Clinical management for other iatrogenic immunodeficiency-associated lymphoproliferative disorders

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD), a category of immunodeficiency-associated LPD according to the World Health Organization classification, is associated with immunosuppressive drugs (ISDs). Several factors, including autoimmune disease (AID) activity, Epstein-Barr virus (EBV) infection, ISD usage, and aging, influence the development of OIIA-LPD, resulting in complicated clinical courses and outcomes. Most OIIA-LPD develops in patients with rheumatoid arthritis using methotrexate (MTX-LPD). The management of MTX-LPD is based on the clinical course, i.e., with/without regression, with/without relapse/regrowth event (RRE), LPD subtype, and ISDs for AIDs after LPD development. There are three clinical courses after ISD withdrawal: regressive LPD without relapse/regrowth (R-G), regressive LPD with RRE (R/R-G), and persistent LPD (P-G). The majority of EBV+ diffuse large B-cell lymphomas are classified in R-G, whereas classic Hodgkin lymphoma is generally classified in R/R-G. Polymorphic LPD (P-LPD) in MTX-LPD develops with heterogeneous pathological features similar to monomorphic LPD. Chemotherapy for MTX-LPD is selected according to that for de novo LPD, although the strategy for aggressive P-LPD and non-specific LPD is not well established. The absolute lymphocyte count in the peripheral blood has been suggested as a candidate marker for MTX-LPD development and RRE. Several clinical issues, including correct diagnosis among overlapping clinicopathological features in MTX-LPD and clinical management of LPD by ISDs other than MTX, require further investigation.

Herpes Simplex virus type 2 myeloradiculitis with a pure motor presentation in a liver transplant recipient

In this case report, we describe the first PCR-confirmed case of HSV2 myeloradiculitis with a purely motor presentation, occurring in a 68-year-old liver transplant recipient. The patient reported ascending weakness with no sensory nor sphincteric symptoms, thereby resembling acute demyelinating inflammatory neuropathy, or Guillain-Barré syndrome. HSV2 was detected in cerebrospinal fluid by PCR, and the patient was successfully treated with intravenous Acyclovir.

[Opportunistic infections by human herpes viruses]

Infections in immunosuppressed patients represent a particular challenge in the diagnostics and treatment. They often present with atypical and particularly severe courses, for which rapid diagnostics and treatment are decisive for treatment success. Opportunistic infections with human herpes viruses occur not only more frequently in immunocompromised patients compared to healthy people but also represent a special challenge. In the treatment of immunosuppressed patients, e.g. with human immunodeficiency virus infections and patients with solid organ transplantations, infections with herpes simplex virus, varicella zoster virus, Epstein-Barr virus and cytomegalovirus are particularly important. The symtoms are very variable, ranging from asymptomatic detection of viremia to vital life-threatening organ manifestations. This review article describes the most important clinical presentations of these opportunistic infections. Furthermore, the diagnostic, therapeutic and prophylactic strategies for human herpes viruses are summarized.

Cutaneous involvement of polymorphic post-transplant lymphoproliferative disorder in a child after liver transplantation

Post-transplantation lymphoproliferative disorder (PTLD) is one of the most common de novo malignancies in patients who receive immunosuppressive therapy after solid organ transplantation. We report a case of a 5-year-old girl who presented with indurated violaceous skin nodules 3.5 years post-liver transplantation, diagnosed as polymorphic PTLD, also involving Waldeyer's ring, spleen, and multiple lymph nodes. Through reduction of immunosuppression, most of the lesions resolved and the liver allograft was preserved.

Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

PTLD with the response-dependent sequential use of RIS, rituximab, and cytotoxic chemotherapy is recommended. Evidence gaps requiring future research and alternate treatment strategies including immunotherapy are highlighted.

Simultaneous detection of opportunistic viral infections among renal transplant patients from Sina Hospital, Tehran

Aim: A proportion of renal transplant (RT) recipients are at high risk for acquisition of opportunistic infections. Methods: A total of 101 plasma and urine specimens were collected from RT patients with raised plasma creatinine. These were tested for three common viral pathogens under suspicion of post-transplant nephropathy. Results: A total of 19 (18.8%), 15 (14.8%) and 10 (9.9%) tested positive for BK virus, cytomegalovirus and Epstein–Barr virus in their plasma and/or urine, respectively. Out of the 19 BK virus positive patients, 12 (63%) were in the tested plasma samples and 17 (89%) were in the urine samples. Four asymptomatic patients had high levels of Epstein–Barr virus shedding in their urine. No co-infected patients showed nephropathy. Conclusion: Relying on plasma creatinine rising levels alone may be an unreliable indicator for evaluating opportunistic viral infections in post-transplant RT subjects.

Posttransplant Malignancy

Posttransplant malignancy is a leading cause of death after solid organ transplantation (SOT). Recipients of SOT are at significantly higher risk of multiple cancers compared with the general population, most notably nonmelanoma skin cancer and posttransplant lymphoproliferative disorders. Risk factors for posttransplant malignancy include history of malignancy, immunosuppression, oncogenic viral infections, sun exposure, and disease-specific associations. Early detection and treatment of malignancies can improve survival.

Epstein-Barr virus post-transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) viremia and post-transplant lymphoproliferative disease (PTLD) are severe complications after hematopoietic stem cell transplantation (HSCT). A series of risk factors have been found to predict EBV viremia and PTLD, including the T-cell depletion, reduced intensity conditioning, and alternative donor. The rituximab pre-emptive therapy could improve PTLD prognosis significantly, but the trigger of initiating rituximab pre-emptive therapy has not been well established. Additionally, EBV-specific cytotoxic T cell (CTL) is a promising approach to treat EBV-PTLD.

Risk factors and long-term outcomes of pediatric liver transplant recipients with chronic high Epstein-Barr virus loads

BACKGROUND

Serial monitoring of Epstein-Barr virus (EBV) reveals that certain pediatric liver transplant (LT) recipients exhibit high EBV loads for long periods. We investigated the incidence and risk factors of chronic high EBV (CHEBV) loads (continuous EBV DNA >10 000 IU/mL of whole blood for ≥6 months) and long-term outcomes.

METHODS

This single center, retrospective observational study investigated pediatric LT recipients who survived ≥6 months. We quantitated EBV DNA weekly during hospitalization and subsequently every 4 or 6 weeks at the outpatient clinic. Tacrolimus was maintained at a low trough level (<3 ng/mL, EBV DNA load >5000 IU/mL).

RESULTS

Thirty-one of 77 LT recipients developed CHEBV. Univariate analysis revealed that age <2 years and body weight <10 kg upon LT, operation time <700 minutes, warm ischemia time (WIT) >35 minutes, graft-to-recipient weight ratio (GRWR) >2.7%, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Multivariate analysis identified significant associations of CHEBV with WIT >35 minutes, GRWR >2.7%, and preoperative seronegative. None of the recipients developed post-transplantation lymphoproliferative disorder. Survival rates of patients with and without CHEBV loads were not significantly different.

CONCLUSIONS

A significant number of pediatric LT recipients developed CHEBV loads. Long WIT, high GRWR, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Although the long-term outcomes of patients with or without CHEBV loads were not significantly different, further studies of more subjects are warranted.

Posttransplant Lymphoproliferative Disorder Presenting as Testicular Lymphoma in a Kidney Transplant Recipient: A Case Report and Review of the Literature

Posttransplant lymphoproliferative disorder (PTLD) is a malignancy caused by the immunosuppression that occurs after transplantation. It is primarily a nodal lesion but frequently it involves extranodal masses. Treatment is usually by reducing immunosuppressive therapy. Testicular lymphoma as PTLD is notably rare in documented literature and there is limited evidence of definitive treatment guidelines. This manuscript describes a patient who developed diffuse large B-cell lymphoma of his right testis one year following kidney transplantation. A diagnosis of PTLD was made and treatment with rituximab, locoregional radiotherapy, and intrathecal methotrexate in addition to the standard reduction of immunosuppression resulted in complete remission until now. We submit this case along with literature review of similar cases in the past and a review of specific peculiarities of our case with emphasis on our treatment plan to further the understanding of this diversiform disease.

Kinetics of Double-Stranded DNA Viremia After Allogeneic Hematopoietic Cell Transplantation

Background

Improved understanding of double-stranded DNA (dsDNA) virus kinetics after hematopoietic cell transplantation (HCT) would facilitate development of therapeutic strategies.

Methods

We tested weekly plasma samples from 404 patients through day 100 after allogeneic HCT for cytomegalovirus (CMV), human herpesvirus (HHV) 6A and 6B, BK polyomavirus (BKV), adenovirus (AdV), and Epstein-Barr virus (EBV) using quantitative polymerase chain reaction. Episodes lasting ≤1 week were defined as blips and >1 week as persistent. We described virus-specific kinetics, analyzed the association of virus area under the curve (AUC) with overall mortality, and identified risk factors for persistent episodes.

Results

We identified 428 episodes of CMV, 292 of BKV, 224 of HHV-6B, 46 of AdV, and 53 of EBV. CMV and BKV had the highest proportions of persistent episodes (68% and 80%, respectively). Detection and kinetics varied by virus. HHV-6B episodes reached maximum levels fastest and had the shortest intervals between detection and end-organ disease. End-organ disease occurred within 14 days of viremia in 68% of cases, generally during persistent episodes. For all viruses, higher viral load AUC increased risk for overall mortality through day 365, persistent episodes had higher viral load than blips, and higher first positive viral load significantly increased risk for persistent episodes. First viral load >2 log10 copies/mL (range, 2.04-3.06 per virus) had high specificity for persistent episodes.

Conclusions

Persistent high viral load dsDNA viremia episodes after allogeneic HCT predict mortality. Virus-specific kinetics can guide timing and thresholds for early intervention in studies of novel agents.

Posttransplant Lymphoproliferative Disorder: Otolaryngological Manifestations and Management

Objective

Posttransplant lymphoproliferative disorder (PTLD) is a unifying term for a spectrum of lymphoid expansion entities brought about by immunosuppression and is strongly associated with Epstein-Barr virus (EBV). Otolaryngological findings tend to present early in the clinical course; therefore, disease awareness among otolaryngologists is of utmost importance. This review synthesizes the body of literature pertaining to PTLD involving the head and neck, summarizes contemporary management, and highlights areas for future research.

Data Sources

PubMed/Medline.

Review Methods

Primary literature search of the Medline database was performed for all titles published in the past 10 years pertaining to PTLD. The database search included PTLD combined with a collection of otolaryngological MeSH terms. Full manuscripts were reviewed based on relevance of their title and abstract. Selection into this review was according to clinical and scientific relevance.

Conclusion

Adenotonsillar focus is common in children in whom adenotonsillectomy may be diagnostic and prevents potentially morbid airway obstruction. Sinonasal PTLD may mimic fungal infection. Laryngotracheal involvement predominately presents in children with symptoms of airway obstruction. PTLD limited to the esophagus is rare. Oral PTLD is rare and phenotypically varied. Cutaneous presentation of PTLD is infrequent, yet one-third of cases affects the head and neck. PTLD may present as cervical lymphadenopathy.

Implications for Practice

PTLD consideration is vital when evaluating posttransplant patients. Children and EBV-seronegative patients should receive otolaryngological follow-up after transplant. PTLD treatment is multidisciplinary and typically led by lymphoma specialists. Formal partnerships between otolaryngologists and transplant centers may improve patient care and research quality.

Acute liver dysfunction not resulting from hepatitis virus in immunocompetent children

BACKGROUND

The aim of the present study was to clarify the roles of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6) in immunocompetent children with acute liver dysfunction not resulting from hepatitis virus.

METHODS

Sixty-eight children (median age, 3 years) hospitalized as a result of acute liver dysfunction were enrolled in this study. Hepatitis A, B, and C were excluded. The prevalence of CMV, EBV, and HHV-6 and viral DNA load in whole blood was prospectively evaluated on multiplex real-time polymerase chain reaction (PCR).

RESULTS

Of the 68 children with acute liver dysfunction, multiplex real-time PCR was positive in 30 (44%). CMV, EBV, and HHV-6 DNA were detected in 13 (19%), 14 (21%), and seven (10%), respectively. Serum CMV immunoglobulin (Ig)G/IgM and EBV viral capsid antigen IgG/IgM were measured in 40 (CMV DNA positive, n = 10; negative, n = 30) and 45 (EBV DNA positive, n = 14; negative, n = 31) of the 68 children, respectively. Eighteen percent (CMV, 7/40) and 9% (EBV, 4/45) were positive for both PCR and viral-specific IgM. There was no significant difference in CMV and EBV viral load between IgM-positive and -negative children with viremia.

CONCLUSIONS

CMV, EBV, and HHV-6 DNA were frequently detected in immunocompetent children with acute liver dysfunction, but primary CMV and EBV infection were confirmed in 10-20% of the children with acute liver dysfunction. The combination of PCR assay and serology is necessary to make a diagnosis of acute liver dysfunction due to primary CMV, EBV and/or HHV-6 infection in immunocompetent children.

Peripheral Blood Epstein-Barr Viral Nucleic Acid Surveillance as a Marker for Posttransplant Cancer Risk

Several viruses, such as Epstein-Barr virus, are now known to be associated with several human cancers, but not all patients with these viral infections develop cancer. In transplantation, such viruses often have a prolonged time gap from infection to cancer development, and many are preceded by a period of circulating and detectable nucleic acids in the peripheral blood compartment. The interpretation of a viral load as a measure of posttransplant risk of developing cancer depends on the virus, the cancer and associated pathogenic factors. This review describes the current state of knowledge regarding the utility and limitations of peripheral blood nucleic acid testing for Epstein-Barr virus in surveillance and risk prediction for posttransplant lymphoproliferative disorders.

Asymptomatic Epstein-Barr Virus Shedding in the Urine of Kidney Transplant Recipients: Case Reports and Review of the Literature

Epstein-Barr virus (EBV) is associated with a wide range of malignancies and complications like post-transplant lymphoproliferative disorder (PTLD). To suppress active EBV infection in transplant recipients, who are at a heightened risk of developing PTLD, EBV DNAemia monitoring has been recommended. Quantitative multiplex real time polymerase chain reaction (QMRTPCR) offered the advantage of detection of more than one target in the same sample. We present four cases of kidney transplant recipient who were admitted for rising serum creatinine between 9 and 20 months post-transplant with a suspicion of BKV-associated nephropathy. All but one patient had unusual sonography findings in their genitourinary tracts and were positive for urinary culture for bacteria. Using a commercial QMRTPCR that could detect and quantitate BKV, EBV and cytomegalovirus simultaneously, all patients were positive for EBV in their urine for the levels between 2500 and 8×10⁸ U/mL. None of the patients had any symptoms regarding this finding. On following up survey 3 month post discharge from hospital, all patients were negative for plasma and urine EBV. Absent of EBV DNAemia together with alternating phases of detectable EBV in urine might reflect the presence of functionally efficient central/effector memory T cells against EBV. The significance of this finding in immunocompromized patients necessitates prospective longitudinal studies.

Epstein-Barr virus and renal transplantation

Epstein-Barr virus (EBV) is a gamma herpesvirus associated with diseases ranging from asymptomatic viremia to post-transplant malignancies in kidney transplant recipients. EBV specifically is associated with post-transplantation lymphoproliferative disorder (PTLD), in kidney transplant recipients, with increased risk in EBV seronegative patients with EBV seropositive donors on intensified immunosuppression. The diagnosis of PTLD relies on clinical suspicion plus tissue biopsy with polymerase chain reaction (PCR) testing of blood currently used for risk determination in high-risk recipients. Therapeutic strategies for PTLD include reduction of immunosuppression, chemotherapy and rituximab, and consideration of sirolimus-based immunosuppression. Antivirals such as ganciclovir are used to prevent reactivation of cytomegalovirus and other herpes viruses but are not onco-therapeutic. Radiation therapy or surgery is indicated for bulky, disseminated or recalcitrant disease. Prognosis varies depending on the type of malignancy identified and stage of disease.

[Infectious and neoplasic complications after kidney transplantation]

Infections and malignancies are the expected complications of immunosuppressive therapy, which non-specifically impairs cellular and humoral immune responses in renal transplant recipients. Infections were usually frequent and severe during the early post-transplant period (first year). Recent diagnostic methods (molecular biology) and availability of new antivirals, antifungal and antibiotic drugs made rapid diagnosis and systematic preventive strategies much easier and this resulted in a significant reduction of infections and infectious death in this population. However, new infectious agents like BK polyomavirus, hepatitis E virus, parvovirus (as well as Chigunkunya, West Nile and others in particular areas) were recently recognized as responsible of aggressive infections in the immunocompromised host. Malignancies are also common after transplantation, due to the intensity and duration of immunosuppression. Skin cancers and lymphoproliferative disorders are the most common and are undoubtedly caused by viral infections, but incidence of non-skin cancers is also increased. After reduction of immunosuppression, treatment is similar to non-transplant patients: Results are usually poor and cancer is now the third cause of death in transplant recipients. Due to their anti-proliferative and anti-tumoral properties, incidence of de novo cancer significantly decreased in patients receiving mTor inhibitors as maintenance immunosuppression; furthermore, in patients already diagnosed with Kaposi sarcoma or recurrent skin cancers, introduction of mTor was associated with stabilisation and/or regression of malignant lesions.

Primary Epstein-Barr virus infection, seroconversion, and post-transplant lymphoproliferative disorder in seronegative renal allograft recipients: a prospective cohort study

BACKGROUND

Epstein-Barr virus (EBV)-seronegative renal transplant recipients are at risk of post-transplant lymphoproliferative disorder (PTLD). We compared primary EBV infection, seroconversion, and PTLD in EBV-seronegative patients who received renal allograft from seropositive or seronegative donors (D+/R- and D-/R-, respectively).

METHODS

We prospectively followed 25 D+/R- and 8 D-/R- recipients. We followed patients from January 1999 to June 2009 with clinical visits, monthly EBV polymerase chain reaction tests, and serologic tests for a period of 1 year after kidney transplantation and on an individual basis thereafter.

RESULTS

Three patients (9%) developed PTLD including 2 early-onset (<12 months) and 1 late-onset (>12 months) disease. In D+/R- and D-/R- patients, the frequencies of PTLD (8% vs. 12.5%, P = 0.7), EBV seroconversion (64% vs. 50%, P = 0.4), and EBV viremia (40% vs. 25%, P = 0.6) were not significantly different. Clinical, serologic, and virologic surveillance as well as reduction in immunosuppression after evidence of primary EBV infection resulted in a PTLD rate of 9%, despite a seroconversion rate of 60.6%. Rate of graft loss after reduction in immunosuppression was 10% (2 of 20), which was not significantly different from 13 patients without EBV seroconversion (no graft loss, P = 0.5). Rates of viremia, seroconversion, and PTLD in D+/R- and D-/R- patients appear to be similar.

CONCLUSIONS

The incidence of PTLD in renal transplants ranges from 0.5% to 2.9%. Our data show a significantly higher rate in EBV-seronegative renal allograft recipients, suggesting the need for close surveillance. Our data also suggest that donors for EBV-seronegative recipients may be accepted irrespective of positive or negative serostatus, with ongoing surveillance important in either circumstance.

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.

Epstein-Barr virus-related post-transplant lymphoproliferative disorder in solid organ transplant recipients

Epstein-Barr virus (EBV) contributes to the pathogenesis of post-transplant lymphoproliferative disease (PTLD) in more than 70% of cases. EBV DNAemia surveillance has been reported to assist in the prevention and treatment of PTLD in hematopoietic stem-cell transplantation (HSCT) recipients. Derived from experience in HSCT and taking into account that PCR-based EBV monitoring techniques are currently available in most solid organ transplant (SOT) centres, there is a great interest in EBV surveillance and prevention of PTLD in SOT recipients. In the present document we have tried to address from a practical perspective different important topics regarding the prevention and management of EBV-related PTLD in SOT. To this end, available information on SOT was analysed and combined with potentially useful data from HSCT and expert observations. The document is therefore structured according to different specific questions, each of them culminating in a consensus opinion of the panel of European experts, grading the answers according to internationally recognized levels of evidence. The addressed issues were grouped under the following topics. (i) Timing and epidemiological data of PTLD. Prophylaxis guided by clinical risk factors of early and late PTLD in SOT. (ii) Relationship of EBV DNAemia load monitoring and the development of PTLD in solid organ transplant recipients. (iii) Monitoring of EBV DNAemia after SOT. Which population should be monitored? What is the optimal timing of the monitoring? (iv) Management of SOT recipients with persistent and/or increasing EBV DNAemia.

The Impact of EBV Status on Characteristics and Outcomes of Posttransplantation Lymphoproliferative Disorder

We examined the associations of Epstein-Barr virus (EBV) status with characteristics and outcomes of posttransplantation lymphoproliferative disorder (PTLD) by studying 176 adult solid organ transplant recipients diagnosed with PTLD between 1990 and 2013 (58 [33%] EBV-negative; 118 [67%] EBV-positive). The proportion of EBV-negative cases increased over time from 10% (1990-1995) to 48% (2008-2013) (p < 0.001). EBV-negative PTLD had distinct characteristics (monomorphic histology, longer latency) though high-risk features (advanced stage, older age, high lactate dehydrogenase, central nervous system involvement) were not more common compared to EBV-positive PTLD. In multivariable analysis, EBV negativity was not significantly associated with worse response to initial therapy (adjusted odds ratio, 0.84; p = 0.75). The likelihood of achieving a complete remission (CR) was not significantly different for EBV-negative versus EBV-positive PTLD including when therapy was reduction of immunosuppression alone (35% vs. 43%, respectively, p = 0.60) or rituximab (43% vs. 47%, p = 1.0). EBV negativity was also not associated with worse overall survival (adjusted hazard ratio, 0.91; p = 0.71). Our findings indicate that EBV status is not prognostic or predictive of treatment response in adults with PTLD. The high proportion of EBV-negative disease diagnosed in recent years highlights the need for new strategies for prevention and management of EBV-negative PTLD.

Current preventive strategies and management of Epstein-Barr virus-related post-transplant lymphoproliferative disease in solid organ transplantation in Europe. Results of the ESGICH Questionnaire-based Cross-sectional Survey

There is limited clinical evidence on the utility of the monitoring of Epstein-Barr virus (EBV) DNAemia in the pre-emptive management of post-transplant lymphoproliferative disease (PTLD) in solid organ transplant (SOT) recipients. We investigated current preventive measures against EBV-related PTLD through a web-based questionnaire sent to 669 SOT programmes in 35 European countries. This study was performed on behalf of the ESGICH study group from the European Society of Clinical Microbiology and Infectious Diseases. A total of 71 SOT programmes from 15 European countries participated in the study. EBV serostatus of the recipient is routinely obtained in 69/71 centres (97%) and 64 (90%) have access to EBV DNAemia assays. EBV monitoring is routinely used in 85.9% of the programmes and 77.4% reported performing pre-emptive treatment for patients with significant EBV DNAemia levels. Pre-emptive treatment for EBV DNAemia included reduction of immunosuppression in 50.9%, switch to mammalian target of rapamycin inhibitors in 30.9%, and use of rituximab in 14.5% of programmes. Imaging by whole-body 18-fluoro-deoxyglucose positron emission tomography (FDG-PET) is used in 60.9% of centres to rule out PTLD and complemented computer tomography is used in 50%. In 10.9% of centres, FDG-PET is included in the first-line diagnostic workup in patients with high-risk EBV DNAemia. Despite the lack of definitive evidence, EBV load measurements are frequently used in Europe to guide diagnostic workup and pre-emptive reduction of immunosuppression. We need prospective and controlled studies to define the impact of EBV monitoring in reducing the risk of PTLD in SOT recipients.

Lymphomatoid granulomatosis--a single institute experience: pathologic findings and clinical correlations

Lymphomatoid granulomatosis (LYG) is a rare angiocentric and angiodestructive Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorder. It is hypothesized that these patients have dysregulated immune surveillance of EBV. We reviewed the biopsies of 55 patients with LYG who were referred for a prospective trial at the National Cancer Institute (1995 to 2010) and evaluated the histologic, immunohistochemical, in situ hybridization, and molecular findings of these biopsies in conjunction with clinical information. Grading of the lesions was based on morphologic features and the number of EBV-positive B cells. The median age was 46 years (M:F 2.2:1). Clinically, all patients had lung involvement (100%), with the next most common site being the central nervous system (38%). No patient had nodal or bone marrow disease. All patients had past EBV exposure by serology but with a low median EBV viral load. We reviewed 122 biopsies; the most common site was lung (73%), followed by skin/subcutaneous tissue (17%); other sites included kidney, nasal cavity, gastrointestinal tract, conjunctiva, liver, and adrenal gland. Histologically, the lesions showed angiocentricity, were rich in T cells, had large atypical B cells, and were positive for EBV. Grading was performed predominantly on the lung biopsy at diagnosis; they were distributed as follows: LYG grade 1 (30%), grade 2 (22%), and grade 3 (48%). Necrosis was seen in all grades, with a greater degree in high-grade lesions. Immunoglobulin gene rearrangement studies were performed, and a higher percentage of clonal rearrangements were seen in LYG grade 2 (50%) and grade 3 (69%) as compared with grade 1 (8%). LYG is a distinct entity that can usually be differentiated from other EBV-associated B-cell lymphoproliferative disorders on the basis of the combination of clinical presentation, histology, and EBV studies. Grading of these lesions is important because it dictates the treatment choice.

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.

Epstein-Barr virus serology and PCR: conflicting results in an immunocompetent host. A case report and review of literature

We present the case of a 27-year-old immunocompetent man who progressively developed a generalized lymphadenopathy and B symptoms. Results of Epstein-Barr virus (EBV) serology were suggestive for a past infection, but the EBV viral load in whole blood was high. Also, core needle biopsy of the largest lymph node showed an image which could fit an EBV-driven reactive lymphoproliferation. Despite the absence of an immune disorder, all medical evidence points to an EBV-driven lymphoproliferative proces. In immunocompetent patients, it seems extremely uncommon to detect a high EBV viral load in the absence of serological evidence of an acute EBV infection or reactivation. We reviewed literature on this topic and on the selection of the appropriate sample type for EBV PCR, as this is known to be a critical point. Serological testing for the diagnosis of EBV infection is the gold standard in immunocompetent patients. Measuring EBV viral load is only recommended when dealing with immunocompromised patients. Although extremely rare, this case report shows that there is a place for EBV PCR in certain situations in immunocompetent patients. Besides, there is still no consensus regarding the specimen of choice for the determination of the EBV viral load. The preferred specimen type seems to depend on the patient's underlying condition.

Epstein-Barr virus infection in adult renal transplant recipients

Epstein-Barr virus (EBV) DNAemia in the first year posttransplantation has been studied extensively. There is a paucity of information on prevalence and sequelae of EBV infection in adult renal transplantation beyond the first year. This single-center study examines the relationship between EBV DNAemia and demographic, immunosuppressive, hematologic and infection-related parameters in 499 renal transplant recipients between 1 month and 33 years posttransplant. Participants were tested repeatedly for EBV DNAemia detection over 12 months and clinical progress followed for 3 years. Prevalence of DNAemia at recruitment increased significantly with time from transplant. In multivariate adjusted analyses, variables associated with DNAemia included EBV seronegative status at transplant (p = 0.045), non-White ethnicity (p = 0.014) and previous posttransplant lymphoproliferative disease (PTLD) diagnosis (p = 0.006), while low DNAemia rates were associated with mycophenolate mofetil use (p < 0.0001) and EBV viral capsid antigen positive Epstein-Barr nuclear antigen-1 positive serostatus at transplant (p = 0.044). Patient and graft survival, rate of kidney function decline and patient reported symptoms were not significantly different between EBV DNAemia positive and negative groups. EBV DNAemia is common posttransplant and increases with time from transplantation, but EBV DNAemia detection in low-risk (seropositive) patients has poor specificity as a biomarker for future PTLD risk.

Duplex realtime PCR method for Epstein-Barr virus and human DNA quantification: its application for post-transplant lymphoproliferative disorders detection

Introduction

The quantification of circulating Epstein–Barr virus (EBV) DNA is used to monitor transplant patients as an early marker of Post-Transplant Lymphoproliferative Disorders (PTLD). So far no standardized methodology exists for such determination.

Objective

Our purpose was to develop and validate a real-time PCR assay to quantify EBV DNA in clinical samples from transplant recipients.

Methods

A duplex real-time PCR method was developed to amplify DNA from EBV and from a human gene. The EBV load was determined in peripheral blood mononuclear cells (PBMC), plasma and oropharyngeal tissue from 64 non-transplanted patients with lymphoid-hypertrophy (Non-Tx), 47 transplant recipients without PTLD (Tx), 54 recipients with PTLD (Tx-PTLD), and 66 blood donors (BD). WinPEPI, version 11.14 software was used for statistical analysis.

Results

Analytical validation: the intra and inter-assays variation coefficients were less than 4.5% (EBV-reaction) and 3% (glyceraldehyde 3-phosphate dehydrogenase – GAPDH reaction). Linear ranges comprised 10⁷–10 EBV genome equivalents (gEq) (EBV-reaction) and 500,000–32 human gEq (GAPDH-reaction). The detection limit was 2.9 EBV gEq (EBV-reaction). Both reactions showed specificity. Application to clinical samples: higher levels of EBV were found in oropharyngeal tissue from transplanted groups with and without PTLD, compared to Non-Tx (p < 0.05). The EBV load in PBMC from the groups of BD, Non-Tx, Tx and Tx-PTLD exhibited increasing levels (p < 0.05). In BD, PBMC and plasma, EBV loads were undetectable.

Conclusions

The performance of the assay was suitable for the required clinical application. The assay may be useful to monitor EBV infection in transplant patients, in particular in laboratories from low-income regions that cannot afford to use commercial assays.

Prevention and treatment for Epstein-Barr virus infection and related cancers

Epstein-Barr virus (EBV) was the first herpes virus described as being oncogenic in humans. EBV infection is implicated in post-transplant lymphoproliferative diseases (PTLD) and several other cancers in non-immunocompromised patients, with more than 200,000 new cases per year. While prevention of PTLD is improving, mainly based on EBV monitoring and preemptive tapering of immunosuppression, early diagnosis remains the best current option for the other malignancies. Significant progress has been achieved in treatment, with decreased mortality and morbidity, but some challenges are still to face, especially for the more aggressive diseases. Possible prevention by EBV vaccination would be a more global approach of this public health problem, but further active research is needed before this goal could be reached.

Analytical characterization of an assay designed to detect and identify diverse agents of disseminated viral infection

BACKGROUND

Diverse viruses often reactivate in or infect cancer patients, patients with immunocompromising infections or genetic conditions, and transplant recipients undergoing immunosuppressive therapy. These infections can disseminate, leading to death, transplant rejection, and other severe outcomes.

OBJECTIVES

To develop and characterize an assay capable of inclusive and accurate identification of diverse potentially disseminating viruses directly from plasma specimens.

STUDY DESIGN

We developed a PCR/electrospray ionization mass spectrometry (PCR/ESI-MS) assay designed to simultaneously detect and identify adenovirus, enterovirus, polyomaviruses JC and BK, parvovirus B19, HSV-1, HSV-2, VZV, EBV, CMV, and herpesviruses 6-8 in plasma specimens. The assay performance was characterized analytically, and the results from clinical plasma samples were compared to the results obtained from single-analyte real time PCR tests currently used in clinical practice.

RESULTS

The assay demonstrated sensitivity and specificity to diverse strains of the targeted viral families and robustness to interfering substances and potentially cross reacting organisms. The assay yielded 94% sensitivity when testing clinical plasma samples previously identified as positive using standard-of-care real-time PCR tests for a single target virus (available samples included positive samples for 11 viruses targeted by the assay).

CONCLUSIONS

The assay functioned as designed, providing simultaneous broad-spectrum detection and identification of diverse agents of disseminated viral infection. Among 156 clinical samples tested, 37 detections were made in addition to the detections matching the initial clinical positive results.

Sensitive, microliter PCR with consensus degenerate primers for Epstein Barr virus amplification

Sensitive identification of the etiology of viral diseases is key to implementing appropriate prevention and treatment. The gold standard for virus identification is the polymerase chain reaction (PCR), a technique that allows for highly specific and sensitive detection of pathogens by exponentially amplifying a specific region of DNA from as little as a single copy through thermocycling a biochemical cocktail. Today, molecular biology laboratories use commercial instruments that operate in 0.5-2 h/analysis using reaction volumes of 5-50 μL contained within polymer tubes or chambers. Towards reducing this volume and maintaining performance, we present a semi-quantitative, systematic experimental study of how PCR yield is affected by tube/chamber substrate, surface-area-to-volume ratio (SA:V), and passivation methods. We perform PCR experiments using traditional PCR tubes as well as using disposable polymer microchips with 1 μL reaction volumes thermocycled using water baths. We report the first oil encapsulation microfluidic PCR method without fluid flow and its application to the first microfluidic amplification of Epstein Barr virus using consensus degenerate primers, a powerful and broad PCR method to screen for both known and novel members of a viral family. The limit of detection is measured as 140 starting copies of DNA from a starting concentration of 3 × 10(5) copies/mL, regarded as an accepted sensitivity threshold for diagnostic purposes, and reaction specificity was improved as compared to conventional methods. Also notable, these experiments were conducted with conventional reagent concentrations, rather than commonly spiked enzyme and/or template mixtures. This experimental study of the effects of substrate, SA:V, and passivation, together with sensitive and specific microfluidic PCR with consensus degenerate primers represent advances towards lower cost and higher throughput pathogen screening.