Infectious mononucleosis

Retinal vasculitis associated with Epstein-Barr virus infection in a young immunocompetent patient. First Colombian case report

Introduction: Epstein - Barr virus (EBV) infection is usually asymptomatic and persists throughout life. Eye involvement is rare, and even though there are some case reports, none of them comes from Colombia or Latin America.Case presentation: Immunocompetent young man with generalized unilateral retinal vasculitis, temporal and inferonasal bloodless vessels in the periphery, intraretinal hemorrhages, intense vitritis and retinal detachment. Epstein-Barr virus presence was determined using a polymerase chain reaction technique in vitreous humor. The patient recovered visual acuity with conventional antiviral oral treatment.Discussion: Eye involvement associated with Epstein-Barr virus is observed in immunocom­promised patients, especially with HIV infection, where retinal involvement may occur. This case reports the presence of this pathology in an immunocompetent patient.Conclusions: Retinal vasculitis is a rare entity, frequently associated with immunocompromise. There is no diagnostic algorithm for this disease and eye involvement may be variable; there are no standard lines of treatment either. The evidence reported here explains the need for studies in selected patients showing visual acuity involve­ment without an established etiology.

CD8+ T cells retain protective functions despite sustained inhibitory receptor expression during Epstein-Barr virus infection in vivo

Epstein Barr virus (EBV) is one of the most ubiquitous human pathogens in the world, persistently infecting more than 90% of the adult human population. It drives some of the strongest human CD8⁺ T cell responses, which can be observed during symptomatic primary infection known as infectious mononucleosis (IM). Despite high viral loads and prolonged CD8⁺ T cell stimulation during IM, EBV enters latency and is under lifelong immune control in most individuals that experience this disease. We investigated whether changes in T cell function, as frequently characterized by PD-1 up-regulation, occur during IM due to the prolonged exposure to high antigen levels. We readily detected the expansion of PD-1 positive CD8⁺ T cells together with high frequencies of Tim-3, 2B4, and KLRG1 expression during IM and in mice with reconstituted human immune system components (huNSG mice) that had been infected with a high dose of EBV. These PD-1 positive CD8⁺ T cells, however, retained proliferation, cytokine production, and cytotoxic abilities. Multiple subsets of CD8⁺ T cells expanded during EBV infection, including PD-1⁺Tim-3⁺KLRG1⁺ cells that express CXCR5 and TCF-1 germinal center homing and memory markers, and may also contain BATF3. Moreover, blocking the PD-1 axis compromised EBV specific immune control and resulted in virus-associated lymphomagenesis. Finally, PD-1⁺, Tim-3⁺, and KLRG1⁺ CD8⁺ T cell expansion coincided with declining viral loads during low dose EBV infection. These findings suggest that EBV infection primes PD-1 positive CD8⁺ T cell populations that rely on this receptor axis for the efficient immune control of this ubiquitous human tumor virus.

Since its discovery as a tumor virus by Epstein and colleagues in 1964, Epstein-Barr virus (EBV) has been implicated in many serious diseases, including infectious mononucleosis, Burkitt’s lymphoma, and post-transplant lymphoproliferative disease. Currently, in vivo studies are lacking to understand the comprehensive immune control of EBV in most healthy virus carriers, and, in particular, the characteristics of the CD8⁺ T cells involved in this process. We find that even though CD8⁺ T cells express multiple inhibitory receptors including PD-1 during primary EBV infection, they appear to retain an ability to produce cytokines, to kill infected cells, and to proliferate. Importantly, blocking the PD-1 pathway leads to defects in EBV-specific control and increased virus-induced tumor formation, indicating that this axis is important for viral control. This is in contrast to previous studies where releasing an inhibitory block is important for reinvigorating immune responses against cancer. Because PD-1 function is required to keep EBV in check, this study provides evidence against blocking co-inhibitory pathways in disease settings that require improved immune control of chronic virus infections.

EBV-related Cold Agglutinin Disease Presenting With Conjugated Hyperbilirubinemia: A Pediatric Case Report and Mini Review

Hemolytic anemia occurs in only 1% to 3% of hospitalized patients with infectious mononucleosis. The authors describe an 8-year-old girl without cervical lymphadenopathy or splenomegaly, who presented with conjugated hyperbilirubinemia and was diagnosed with cold agglutinin disease caused by an immunoglobulin M autoantibody with anti-i specificity. Acute Epstein-Barr virus infection was confirmed by serologic and molecular methods. She recovered uneventfully after a 3-week course of methylprednisolone. Epstein-Barr virus infection should be considered in any case of hemolytic anemia associated with hepatic dysfunction, especially when direct antiglobulin test is positive for C3d. In these cases, a course of corticosteroids seems safe and may be beneficial.

Prophylactic and therapeutic strategies for Epstein-Barr virus-associated diseases: emerging strategies for clinical development

INTRODUCTION

Epstein-Barr virus (EBV) infects more than 95% of the world's population and is associated with infectious mononucleosis as well as a number of cancers in various geographical locations. Despite its significant health burden, no licenced prophylactic or therapeutic vaccines are available. Areas covered: Over the last two decades, our understanding of the role of EBV infection in the pathogenesis and immune regulation of EBV-associated diseases has provided new lines of research to conceptualize various novel prophylactic and therapeutic approaches to control EBV-associated disease. In this review, we evaluate the prophylactic and therapeutic vaccine approaches against EBV and various immunotherapeutic strategies against a number of EBV-associated malignancies. This review also describes the existing and future prospects of improved EBV-targeted therapeutic strategies. Expert opinion: It is anticipated that these emerging strategies will provide answers for the major challenges in EBV vaccine development and help improve the efficacy of novel therapeutic strategies.

Heterologous prime-boost vaccination protects against EBV antigen-expressing lymphomas

The Epstein-Barr virus (EBV) is one of the predominant tumor viruses in humans, but so far no therapeutic or prophylactic vaccination against this transforming pathogen is available. We demonstrated that heterologous prime-boost vaccination with the nuclear antigen 1 of EBV (EBNA1), either targeted to the DEC205 receptor on DCs or expressed from a recombinant modified vaccinia virus Ankara (MVA) vector, improved priming of antigen-specific CD4+ T cell help. This help supported the expansion and maintenance of EBNA1-specific CD8+ T cells that are most efficiently primed by recombinant adenoviruses that encode EBNA1. These combined CD4+ and CD8+ T cell responses protected against EBNA1-expressing T and B cell lymphomas, including lymphoproliferations that emerged spontaneously after EBNA1 expression. In particular, the heterologous EBNA1-expressing adenovirus, boosted by EBNA1-encoding MVA vaccination, demonstrated protection as a prophylactic and therapeutic treatment for the respective lymphoma challenges. Our study shows that such heterologous prime-boost vaccinations against EBV-associated malignancies as well as symptomatic primary EBV infection should be further explored for clinical development.

Mononucleosis Epstein -Barr negativa: variación poco reconocida de enfermedad popular

Se reporta el caso de un paciente joven, inmunocompetente y sin factores de riesgo, con adenopatías cervicales, fiebre, malestar general compatible síndrome mononucleósico. La persistencia de síntomas a pesar de múltiples tratamientos con antibióticos lleva a los médicos tratantes a echar un segundo vistazo. El hallazgo y desenlace, los hallarás aquí.

Clinical differentiation of infectious mononucleosis that is caused by Epstein-Barr virus or cytomegalovirus: A single-center case-control study in Japan

Introduction

Infectious mononucleosis (IM) is a common viral infection that typically causes fever, pharyngitis, and lymphadenopathy in young patients. The Epstein-Barr virus (EBV) is the most common cause of IM, followed by cytomegalovirus (CMV). Given that serological testing is associated with limitations regarding its accuracy, availability, and time to receive results, clinical differentiation based on symptoms, signs, and basic tests would be useful. We evaluated whether clinical findings could be used to differentiate EBV-IM from CMV-IM.

Methods

In this single-center retrospective case-control study, we evaluated >14-year-old patients with serologically confirmed EBV-IM or CMV-IM during 2006–2017. We compared the patients’ symptoms, physical findings, blood counts, and serum biomarkers to create three regression models: model 1 (symptoms and signs), model 2 (model 1 plus sonographic hepatosplenomegaly and blood counts), and model 3 (model 2 plus hepatobiliary biomarkers).

Results

Among the 122 patients (72.6%) with EBV-IM and 46 patients (27.4%) with CMV-IM, the median age was 25 years and 82 patients (48.8%) were male. The median age was 10 years older in the CMV-IM group (p < 0.001) and the median interval from onset to visit was 5 days longer in the CMV-IM group (p < 0.001). Logistic regression revealed that EBV-IM was predicted by younger age, short onset-to-visit interval, lymphadenopathy, tonsillar white coat, hepatosplenomegaly, atypical lymphocytosis, and elevations of lactate dehydrogenase and gamma-glutamyl transferase. All regression models had areas under the curve of >0.9.

Conclusion

History and physical findings, especially when used with atypical lymphocytosis and sonographic hepatosplenomegaly, can help physicians differentiate EBV-IM from CMV-IM.

Rare case of Visceral form of Infectious Mononucleosis in Irkutsk Region

Infectious mononucleosis (MI) is caused by the Herpes viridae family of viruses. Currently, most researchers assign a leading role to the Epstein-Barr virus. In present time there are no unified clinical classification of infection mononucleosis, but many authors recognize the visceral form which involves cardiovascular system, adrenal glands, lungs, central neural system and others organs. The article describes a clinical case of MI in the 28-year-old patient. She applied for medical help with complaints of fever up to 39 °C, weakness in the legs and arms, weight loss and received symptomatic treatment on an outpatient department. After 2 months on the background of deterioration, she was hospitalized in an infectious diseases hospital with severe symptoms of intoxication, lymphoproliferative syndrome, myocarditis, pericarditis, hepatitis, polyneuropathy with quadriparesis, hypochromic anemia, thrombocytopenia. She was consulted by an oncologist and diagnosed with cervical cancer. Laboratory confirmation was obtained – Epstein-Barr virus was detected in the blood. Against the background of antiviral therapy, a regression of clinical symptoms was achieved in a week. The patient was transferred to a oncological hospital. It is recommended to examine patients with high fever of unknown etiology on myocardial infarction for the timely appointed etiotropic therapy.

Infections of the Oropharynx

This article reviews the presentation, diagnosis, and management of common and "can't miss" infections of the oropharynx, including streptococcal pharyngitis, infectious mononucleosis, peritonsillar abscess, retropharyngeal abscess, and epiglottitis.

Acute gastritis caused by concurrent infection with Epstein-Barr virus and cytomegalovirus in an immunocompetent adult

Herein, we describe an extremely rare case of gastritis due to concurrent infection with Epstein-Barr virus (EBV) and cytomegalovirus (CMV) occurring in an immunocompetent adult. The patient was a 35-year-old man who presented with slight fever, nausea, anorexia, weight loss for 3 weeks, mild transaminitis, and leukocytosis with atypical lymphocytes in peripheral blood. The clinical presentation and elevated IgM titers to both EBV-VCA and CMV strongly suggested infectious mononucleosis syndrome caused by co-infection with EBV and CMV. A computed tomographic scan of the abdomen showed diffuse thickening of the gastric wall mimicking linitis plastica, and upper endoscopy revealed thickened and eroded mucosa throughout the stomach. Histologic examination of gastric biopsies showed a dense lymphoid and neutrophilic infiltrate in the lamina propria with erosion. In situ hybridization assay revealed many lymphocytes positive for EBV-encoded RNA. Moreover, immunohistochemistry using an anti-CMV monoclonal antibody identified some CMV-positive cells (i.e. foveolar epithelium and endothelium). We finally diagnosed this case as gastric involvement in infectious mononucleosis, and the patient recovered without the administration of antiviral drugs. To our knowledge, this is the first reported case of gastritis co-infected with EBV and CMV, as a manifestation of infectious mononucleosis in an immunocompetent adult.

Poly(ADP-ribose) polymerase 1 is necessary for coactivating hypoxia-inducible factor-1-dependent gene expression by Epstein-Barr virus latent membrane protein 1

Latent membrane protein 1 (LMP1) is the major transforming protein of Epstein-Barr virus (EBV) and is critical for EBV-induced B-cell transformation in vitro. Poly(ADP-ribose) polymerase 1 (PARP1) regulates accessibility of chromatin, alters functions of transcriptional activators and repressors, and has been directly implicated in transcriptional activation. Previously we showed that LMP1 activates PARP1 and increases Poly(ADP-ribos)ylation (PARylation) through PARP1. Therefore, to identify targets of LMP1 that are regulated through PARP1, LMP1 was ectopically expressed in an EBV-negative Burkitt’s lymphoma cell line. These LMP1-expressing cells were then treated with the PARP inhibitor olaparib and prepared for RNA sequencing. The LMP1/PARP targets identified through this RNA-seq experiment are largely involved in metabolism and signaling. Interestingly, Ingenuity Pathway Analysis of RNA-seq data suggests that hypoxia-inducible factor 1-alpha (HIF-1α) is an LMP1 target mediated through PARP1. PARP1 is acting as a coactivator of HIF-1α-dependent gene expression in B cells, and this co-activation is enhanced by LMP1-mediated activation of PARP1. HIF-1α forms a PARylated complex with PARP1 and both HIF-1α and PARP1 are present at promoter regions of HIF-1α downstream targets, leading to accumulation of positive histone marks at these regions. Complex formation, PARylation and binding of PARP1 and HIF-1α at promoter regions of HIF-1α downstream targets can all be attenuated by PARP1 inhibition, subsequently leading to a buildup of repressive histone marks and loss of positive histone marks. In addition, LMP1 switches cells to a glycolytic ‘Warburg’ metabolism, preferentially using aerobic glycolysis over mitochondrial respiration. Finally, LMP1+ cells are more sensitive to PARP1 inhibition and, therefore, targeting PARP1 activity may be an effective treatment for LMP1+ EBV-associated malignancies.

Epstein-Barr virus (EBV) is one of the most ubiquitous human viruses, with over 90% of adults worldwide harboring lifelong latent EBV infection in a small fraction of their B-lymphocytes. EBV is known to cause lymphoproliferative disorders and is associated with several other types of cancer, including Hodgkin's lymphoma, Burkitt's lymphoma and Nasopharyngeal carcinoma. However, in most cases, the approach to EBV-positive lymphomas does not differ from EBV-negative lymphomas of the same histology. Latent membrane protein 1 (LMP1) is the major transforming protein of EBV and is critical for EBV-induced B-cell transformation in vitro. LMP1 activates several epigenetic regulators to modify host gene expression, including the chromatin-modifying enzyme Poly(ADP-ribose) polymerase 1, or PARP1. In the current study we have determined that LMP1 can activate PARP1 to increase hypoxia-inducible factor 1-alpha (HIF-1α)-dependent gene expression, leading to a change in host cell metabolism indicative of a ‘Warburg effect’ (aerobic glycolysis). This subsequently provides a proliferative advantage to LMP1-expressing cells. The LMP1-induced increase in HIF-1α-dependent gene expression, alteration of cellular metabolism, and accelerated cellular proliferation, can be offset with the PARP inhibitor olaparib. Therefore, targeting PARP1 activity may be an effective treatment for LMP1+ EBV-associated malignancies.

S-S-PEG-COOH Self-Assembled Monolayer on Gold Surface Enabled a Combined Assay for Serological EBV Antibody Isotypes

PURPOSE

Epstein-Barr virus (EBV) is a ubiquitous human gamma herpes virus that infects human epithelial cells and B lymphocytes. It would be potentially valuable to develop novel combined assays to benefit screening for large panels of samples of EBV infectious diseases.

EXPERIMENTAL DESIGN

A simple antigen-probed biochip that is modified with S-S-PEG-COOH and is used as a label-free high-throughput screening method for a combined detection of EBV capsid antigen IgM antibody, capsid antigen IgG antibody, and nuclear antigen IgG antibody.

RESULTS

This protein biochip has similar feasibility, sensitivity, and specificity in comparison with Liaison chemiluminescent immunoassay (CLIA). Detection limit of the EBV antibodies by the biochip is almost identical to that by CLIA-L (2.91 U mL^-1 vs 3.00 U mL^-1 for EBNA-1 IgG, 8 U mL^-1 vs10 U mL^-1 for EBV-VCA IgG, and 3.5 U mL^-1 vs 10 U mL^-1 for EBV-VCA IgM). Tests of the three serological antibodies against EBV by the biochip are consistent with the CLIA-L method in 274 clinical sera, respectively. Finally, the combined biochip is successfully utilized for diagnostic identification of EBV infection in 14 patients with infectious mononucleosis (IM) and 25 patients with systemic lupus erythematosus SLE, as well as additional 10 known real-time PCR positive patients.

CONCLUSIONS AND CLINICAL RELEVANCE

This biochip format will enable concurrent detection of antibodies against EBV infection and confirm infection status of EBV. It will be a versatile tool for large-scale epidemiological screening in view of its miniaturization and high throughput.

Fatal Septic Shock in a Patient with Hemophagocytic Lymphohistiocytosis Associated with an Infectious Mononucleosis

The authors describe the case of a young woman who developed a clinical pictures resembling a septic shock-related multiple organ dysfunction syndrome a couple of months after having been diagnosed suffering from a hemophagocytic lymphohistiocytosis associated with an infectious mononucleosis. Despite the aggressive treatment, which included antibiotics, vasopressors, IV immunoglobulins, and the use of an extracorporeal device aimed to remove mediators released both during sepsis and the cytokine storm determined by the hemophagocytic lymphohistiocytosis, the patient died. At the autopsy, an extremely uncommon aggressive lymphoma of Epstein-Barr virus-positive T-lymphocytes with systemic involvement was discovered.

Epstein-Barr virus is not detected in mucosal lichen planus

Background

Lichen planus (LP) is a chronic inflammatory, immunological, mucocutaneous disease can affect skin, genital and oral mucosa. Oral lichen planus (OLP) is the most common noninfectious, chronic inflammatory oral disease affecting 1-2% of the general adult population. World Health Organization (WHO) classifies OLP as a potentially malignant disorder. Epstein Barr virus or human herpesvirus-4, is a member of the herpes virus family and one of the most ubiquitous viruses known to human, infecting approximately 90% of the world’s adult population. The virus often infects B lymphocytes resulting in a wide spectrum of mucocutaneous and systemic diseases, ranging from mild lesions to aggressive malignancies. The aim of this study was to investigate expression of the EBV encoded RNAs EBER1 and EBER2 in oral and genital lichen planus and compare results with normal tissues in situ hybridization which is considered the golden standard for detection of EBER.

Material and Methods

A total of 68 biopsies, 25 oral LP, 26 genital LP, 10 oral controls and finally 7 genital controls were analysed using situ hybridization.

Results

All samples had RNA as shown by the control slide, whereas no case contained neither EBER1 nor EBER2.

Conclusions

Based on results from our study EBV is not involved in aetiology of lichen planus.

Key words:Mucosal lichen planus, Epstein - Barr virus.

Hepatitis caused by herpes viruses: A review

Herpes virus hepatitis varies in presentation, ranging from asymptomatic to acute liver failure, in both immunocompetent and immunocompromised individuals. Hepatitis caused by the Herpesviridae family is uncommon and usually results in mild disease. It is also often self-limiting, although in certain populations especially immunosuppressed patients, it can cause severe infections, leading to acute to fulminant hepatic failure. In addition, some isolated cases of fulminant disease in immunocompetent individuals have been reported. As the presentation is frequently non-specific, it is important to maintain a high level of suspicion for these viral etiologies and start empiric therapy with antiviral agents as soon as possible. Liver transplantation is the last resort. Mortality remains high in fulminant hepatic failure caused by Herpesviridae without liver transplantation. Here we review the literatures on hepatitis caused by three members of the Herpesviridae family, cytomegalovirus, Epstein-Barr virus and herpes simplex virus to discuss the epidemiology, diagnostic methods, clinical features and current management, and also to determine which aspects need to be investigated in further detail. Herpesviridae-mediated acute liver failure is rare but is associated with a poor prognosis, even after early treatment.

Post-transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection-prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.

Protective Role of γδ T Cells in Different Pathogen Infections and Its Potential Clinical Application

γδ T cells, a subgroup of T cells based on the γδ TCR, when compared with conventional T cells (αβ T cells), make up a very small proportion of T cells. However, its various subgroups are widely distributed in different parts of the human body and are attractive effectors for infectious disease immunity. γδ T cells are activated and expanded by nonpeptidic antigens (P-Ags), major histocompatibility complex (MHC) molecules, and lipids which are associated with different kinds of pathogen infections. Activation and proliferation of γδ T cells play a significant role in diverse infectious diseases induced by viruses, bacteria, and parasites and exert their potential effector function to effectively eliminate infection. It is well known that many types of infectious diseases are detrimental to human life and health and give rise to high incidence of illnesses and death rate all over the world. To date, there is no comprehensive understanding of the correlation between γδ T cells and infectious diseases. In this review, we will focus on the various subgroups of γδ T cells (mainly Vδ1 T cells and Vδ2 T cells) which can induce multiple immune responses or effective functions to fight against common pathogen infections, such as Mycobacterium tuberculosis, Listeria monocytogenes, influenza viruses, HIV, EBV, and HBV. Hopefully, the gamma-delta T cell study will provide a novel effective way to treat infectious diseases.

Ancient cancers and infection-induced oncogenesis

Cancers have been reported in bone and soft tissue of ancient agricultural populations. Fossilized bones from prehistoric periods provide evidence of tumors but only one example of cancer. Difficulties in diagnosing the causes of lesions in mummified tissue and fossilized bone, and in interpreting the prevalence of cancers from remains, draw attention to the need for complementary approaches to assess the occurrence of cancer in ancient populations. This paper integrates current knowledge about pathogen induction of cancer with phylogenetic analyses of oncogenic pathogens, and concludes that pathogen-induced cancers were probably generally present in ancient historic and prehistoric human populations. Consideration of cancers in extant human populations and wildlife lends credence to this conclusion, with the caveat that the presence of cancers may depend on population-specific exposures to oncogenic parasites and carcinogens.

Acute Gastritis and Splenic Infarction Caused by Epstein-Barr Virus

Epstein-Barr virus (EBV) infection can be presented with various clinical manifestations and different levels of severity when infected. Infectious mononucleosis, which is most commonly caused by EBV infection in children and adolescents, is a clinical syndrome characterized by fatigue, malaise, fever, sore throat, and generalized lymphadenopathy. But rarely, patients with infectious mononucleosis may present with gastrointestinal symptoms and complicated by gastritis, splenic infarction, and splenic rupture. We encountered a 16-year-old girl who presented with fever, fatigue, and epigastric pain. Splenic infarction and EBV-associated gastritis were diagnosed by using esophagogastroduodenoscopy and abdominal computed tomography. Endoscopy revealed a generalized hyperemic nodular lesion in the stomach, and the biopsy findings were chronic gastritis with erosion and positive in situ hybridization for EBV. As splenic infarction and acute gastritis are rare in infectious mononucleosis and are prone to be overlooked, we must consider these complications when an infectious mononucleosis patient presents with gastrointestinal symptom.

Severe acrocyanosis precipitated by cold agglutinin secondary to infection with Mycoplasma pneumoniae in a pediatric patient

This is the first report describing a severe form of cold agglutinin-induced acrocyanosis with cutaneous necrosis after Mycoplasma infection in a 9-year-old patient without any other severe symptoms and laboratory alterations. We also present the results of two non-invasive methods used to determine the viability of tissues, degree of tissue perfusion impairment, and the responsiveness of the microvasculature. Laser Doppler flowmetry and laser speckle contrast imaging, both suitable to measure tissue blood perfusion non-invasively, have been used in the diagnosis and follow-up of various peripheral vascular diseases. In our patient, we demonstrated remarkably reduced microcirculation before the treatment and a significant perfusion increase in the acral regions after pentoxifylline therapy. The investigational techniques were useful tools to assess and quantify the severity of peripheral perfusion disturbances and to monitor the efficacy of the treatment in our patient.

Searching for human oncoviruses: Histories, challenges, and opportunities

Oncoviruses contribute significantly to cancer burden. A century of tumor virological studies have led to the discovery of seven well-accepted human oncoviruses, cumulatively responsible for approximately 15% of human cancer cases. Virus-caused cancers are largely preventable through vaccination. Identifying additional oncoviruses and virus-caused tumors will advance cancer prevention and precision medicine, benefiting affected individuals, and society as a whole. The historic success of finding human oncoviruses has provided a unique lesson for directing new research efforts in the post-sequencing era. Combing the experiences from these pioneer studies with emerging high-throughput techniques will certainly accelerate new discovery and advance our knowledge of the remaining human oncoviruses.

EBV-Positive Lymphoproliferations of B- T- and NK-Cell Derivation in Non-Immunocompromised Hosts

The contribution of Epstein-Barr virus (EBV) to the development of specific types of benign lymphoproliferations and malignant lymphomas has been extensively studied since the discovery of the virus over the last 50 years. The importance and better understanding of the EBV-associated lymphoproliferative disorders (LPD) of B, T or natural killer (NK) cell type has resulted in the recognition of new entities like EBV+ mucocutaneous ulcer or the addition of chronic active EBV (CAEBV) infection in the revised 2016 World Health Organization (WHO) lymphoma classification. In this article, we review the definitions, morphology, pathogenesis, and evolving concepts of the various EBV-associated disorders including EBV+ diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), EBV+ mucocutaneous ulcer, DLBCL associated with chronic inflammation, fibrin-associated DLBCL, lymphomatoid granulomatosis, the EBV+ T and NK-cell LPD of childhood, aggressive NK leukaemia, extranodal NK/T-cell lymphoma, nasal type, and the new provisional entity of primary EBV+ nodal T- or NK-cell lymphoma. The current knowledge regarding the pathogenesis of B-cell lymphomas that can be EBV-associated including Burkitt lymphoma, plasmablastic lymphoma and classic Hodgkin lymphoma will be also explored.

Clinical Mimics: An Emergency Medicine-Focused Review of Streptococcal Pharyngitis Mimics

BACKGROUND

Pharyngitis is a common disease in the emergency department (ED). Despite a relatively low incidence of complications, there are many dangerous conditions that can mimic this disease and are essential for the emergency physician to consider.

OBJECTIVE

This article provides a review of the evaluation and management of group A β-hemolytic Streptococcal (GABHS) pharyngitis, as well as important medical conditions that can mimic this disease.

DISCUSSION

GABHS pharyngitis often presents with fever, sore throat, tonsillar exudates, and anterior cervical lymphadenopathy. History and physical examination are insufficient for the diagnosis. The Centor criteria or McIsaac score can help risk stratify patients for subsequent testing or treatment. Antibiotics may reduce symptom duration and suppurative complications, but the effect is small. Rheumatic fever is uncommon in developed countries, and shared decision making is recommended if antibiotics are used for this indication. Oral analgesics and topical anesthetics are important for symptom management. Physicians should consider alternate diagnoses that may mimic GABHS pharyngitis, which can include epiglottitis, infectious mononucleosis, Kawasaki disease, acute retroviral syndrome, Lemierre's syndrome, Ludwig's angina, peritonsillar abscess, retropharyngeal abscess, and viral pharyngitis. A focused history and physical examination can help differentiate these conditions.

CONCLUSIONS

GABHS may present similarly to other benign and potentially deadly diseases. Diagnosis and treatment of pharyngitis should be based on clinical evaluation. Consideration of pharyngitis mimics is important in the evaluation and management of ED patients.

Infectious mononucleosis and hepatic function

Abnormal hepatic function is common in infectious mononucleosis (IM). However, it remains unknown why increased transferase levels are more common than bilirubin abnormalities in IM. The current study aimed to investigate these associations in the Chinese population. A total of 95 patients with IM (47 males and 48 females) were enrolled in the current study, as well as 95 healthy controls. Patients were sorted by sex. A receiver operating characteristic (ROC) curve was used to determine cut-off values for IM diagnosis and prediction. Crude and adjusted odds ratios (OR) for IM were analyzed using binary logistic regression. It was determined that alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyl transferase (GGT) levels were significantly higher in patients with IM compared with controls; however, total bilirubin (TB) levels were significantly lower in patients with IM. ROCs demonstrated that, if ALT, AST and GGT concentrations were higher than, or if TB was lower than, cut-off values, they were predictive of IM. Binary logistic regression identified that the risk of IM in patients exhibiting high levels of transferases was significantly increased, particularly in males. Crude ORs in ALT quartile 4 were 21.667 and 10.111 for males and females, respectively and adjusted ORs were 38.054 and 9.882, respectively. A significant IM risk of IM was evident in patients with low bilirubin levels and females appeared to be particularly susceptible. For example, crude ORs in quartile 1 were 8.229 and 8.257 for males and females, respectively and adjusted ORs were 8.883 and 10.048, respectively. Therefore, the current study identified a positive association between transferase levels and IM and a negative association between TB and IM. Therefore, the results of the current study indicate that high transferases are suggestive of IM, particularly in males, whereas low TB is suggestive for IM, particularly in females.

Early Epstein-Barr Virus Genomic Diversity and Convergence toward the B95.8 Genome in Primary Infection

Over 90% of the world's population is persistently infected with Epstein-Barr virus. While EBV does not cause disease in most individuals, it is the common cause of acute infectious mononucleosis (AIM) and has been associated with several cancers and autoimmune diseases, highlighting a need for a preventive vaccine. At present, very few primary, circulating EBV genomes have been sequenced directly from infected individuals. While low levels of diversity and low viral evolution rates have been predicted for double-stranded DNA (dsDNA) viruses, recent studies have demonstrated appreciable diversity in common dsDNA pathogens (e.g., cytomegalovirus). Here, we report 40 full-length EBV genome sequences obtained from matched oral wash and B cell fractions from a cohort of 10 AIM patients. Both intra- and interpatient diversity were observed across the length of the entire viral genome. Diversity was most pronounced in viral genes required for establishing latent infection and persistence, with appreciable levels of diversity also detected in structural genes, including envelope glycoproteins. Interestingly, intrapatient diversity declined significantly over time (P < 0.01), and this was particularly evident on comparison of viral genomes sequenced from B cell fractions in early primary infection and convalescence (P < 0.001). B cell-associated viral genomes were observed to converge, becoming nearly identical to the B95.8 reference genome over time (Spearman rank-order correlation test; r = -0.5589, P = 0.0264). The reduction in diversity was most marked in the EBV latency genes. In summary, our data suggest independent convergence of diverse viral genome sequences toward a reference-like strain within a relatively short period following primary EBV infection.IMPORTANCE Identification of viral proteins with low variability and high immunogenicity is important for the development of a protective vaccine. Knowledge of genome diversity within circulating viral populations is a key step in this process, as is the expansion of intrahost genomic variation during infection. We report full-length EBV genomes sequenced from the blood and oral wash of 10 individuals early in primary infection and during convalescence. Our data demonstrate considerable diversity within the pool of circulating EBV strains, as well as within individual patients. Overall viral diversity decreased from early to persistent infection, particularly in latently infected B cells, which serve as the viral reservoir. Reduction in B cell-associated viral genome diversity coincided with a convergence toward a reference-like EBV genotype. Greater convergence positively correlated with time after infection, suggesting that the reference-like genome is the result of selection.

Vaccine Development for Epstein-Barr Virus

Epstein-Barr virus (EBV) is the primary cause of infectious mononucleosis and is associated with several malignancies, including nasopharyngeal carcinoma, gastric carcinoma, Hodgkin lymphoma, Burkitt lymphoma, and lymphomas in immunocompromised persons, as well as multiple sclerosis. A vaccine is currently unavailable. While monomeric EBV gp350 was shown in a phase 2 trial to reduce the incidence of infectious mononucleosis, but not the rate of EBV infection, newer formulations of gp350 including multimeric forms, viruslike particles, and nanoparticles may be more effective. A vaccine that also includes additional viral glycoproteins, lytic proteins, or latency proteins might improve the effectiveness of an EBV gp350 vaccine. Clinical trials to determine if an EBV vaccine can reduce the rate of infectious mononucleosis or posttransplant lymphoproliferative disease should be performed. The former is important since infectious mononucleosis can be associated with debilitating fatigue as well as other complications, and EBV infectious mononucleosis is associated with increased rates of Hodgkin lymphoma and multiple sclerosis. A vaccine to reduce EBV posttransplant lymphoproliferative disease would be an important proof of principle to prevent an EBV-associated malignancy. Trials of an EBV vaccine to reduce the incidence of Hodgkin lymphoma, multiple sclerosis, or Burkitt lymphoma would be difficult but feasible.

Whole transcriptome profiling reveals major cell types in the cellular immune response against acute and chronic active Epstein-Barr virus infection

Epstein-Barr virus (EBV) is a common human pathogen that infects over 95% of the population worldwide. In the present study, the whole transcriptome microarray data were generated from peripheral blood mononuclear cells from Chinese children with acute infectious mononucleosis (AIM) and chronic active EBV infection (CAEBV) that were also compared with a publicly available microarray dataset from a study of American college students with AIM. Our study characterized for the first time a broad spectrum of molecular signatures in AIM and CAEBV. The key findings from the transcriptome profiling were validated with qPCR and flow cytometry assays. The most important finding in our study is the discovery of predominant γδ TCR expression and γδ T cell expansion in AIM. This finding, in combination with the striking up-regulation of CD3, CD8 and CD94, suggests that CD8+ T cells and CD94+ NK cells may play a major role in AIM. Moreover, the unique up-regulation of CD64A/B and its significant correlation with the monocyte marker CD14 was observed in CAEBV and that implies an important role of monocytes in CAEBV. In conclusion, our study reveals major cell types (particularly γδ T cells) in the host cellular immune response against AIM and CAEBV.

Severity of Acute Infectious Mononucleosis Correlates with Cross-Reactive Influenza CD8 T-Cell Receptor Repertoires

Fifty years after the discovery of Epstein-Barr virus (EBV), it remains unclear how primary infection with this virus leads to massive CD8 T-cell expansion and acute infectious mononucleosis (AIM) in young adults. AIM can vary greatly in severity, from a mild transient influenza-like illness to a prolonged severe syndrome. We questioned whether expansion of a unique HLA-A2.01-restricted, cross-reactive CD8 T-cell response between influenza virus A-M1₅₈ (IAV-M1) and EBV BMLF1₂₈₀ (EBV-BM) could modulate the immune response to EBV and play a role in determining the severity of AIM in 32 college students. Only ex vivo total IAV-M1 and IAV-M1+EBV-BM cross-reactive tetramer⁺ frequencies directly correlated with AIM severity and were predictive of severe disease. Expansion of specific cross-reactive memory IAV-M1 T-cell receptor (TCR) Vβ repertoires correlated with levels of disease severity. There were unique profiles of qualitatively different functional responses in the cross-reactive and EBV-specific CD8 T-cell responses in each of the three groups studied, severe-AIM patients, mild-AIM patients, and seropositive persistently EBV-infected healthy donors, that may result from differences in TCR repertoire use. IAV-M1 tetramer⁺ cells were functionally cross-reactive in short-term cultures, were associated with the highest disease severity in AIM, and displayed enhanced production of gamma interferon, a cytokine that greatly amplifies immune responses, thus frequently contributing to induction of immunopathology. Altogether, these data link heterologous immunity via CD8 T-cell cross-reactivity to CD8 T-cell repertoire selection, function, and resultant disease severity in a common and important human infection. In particular, it highlights for the first time a direct link between the TCR repertoire with pathogenesis and the diversity of outcomes upon pathogen encounter.

The pathogenic impact of immune responses that by chance cross-react to unrelated viruses has not been established in human infections. Here, we demonstrate that the severity of acute infectious mononucleosis (AIM), an Epstein-Barr virus (EBV)-induced disease prevalent in young adults but not children, is associated with increased frequencies of T cells cross-reactive to EBV and the commonly acquired influenza A virus (IAV). The T-cell receptor (TCR) repertoire and functions of these cross-reactive T cells differed between mild- and severe-AIM patients, most likely because these two groups of patients had selected different memory TCR repertoires in response to IAV infections encountered earlier. This heterologous immunity may explain variability in disease outcome and why young adults with more-developed IAV-specific memory T-cell pools have more-severe disease than children, who have less-developed memory pools. This study provides a new framework for understanding the role of heterologous immunity in human health and disease and highlights an important developing field examining the role of T-cell repertoires in the mediation of immunopathology.

Epstein-Barr Virus-Specific Immune Control by Innate Lymphocytes

Epstein–Barr virus (EBV) is a potent B cell transforming pathogen in humans. In most persistently EBV-infected individuals, potent cytotoxic lymphocyte responses prevent EBV-associated pathologies. In addition to comprehensive adaptive T cell responses, several innate lymphocyte populations seem to target different stages of EBV infection and are compromised in primary immunodeficiencies that render individuals susceptible to symptomatic EBV infection. In this mini-review, I will highlight the functions of natural killer, γδ T cells, and natural killer T cells during innate immune responses to EBV. These innate lymphocyte populations seem to restrict both lytic replication and transforming latent EBV antigen expression. The mechanisms underlying the recognition of these different EBV infection programs by the respective innate lymphocytes are just starting to become unraveled, but will provide immunotherapeutic strategies to target pathologies that are associated with the different EBV infection programs.

Changes in Tonsil B Cell Phenotypes and EBV Receptor Expression in Children Under 5-Years-Old

BACKGROUND

Palatine tonsils are principally B cell organs that are the initial line of defense against many oral pathogens, as well as the site of infection for others. While the size of palatine tonsils changes greatly in the first five years of life, the cellular changes during this period are not well studied. Epstein Barr virus (EBV) is a common orally transmitted virus that infects tonsillar B cells. Naïve B cells are thought to be the target of primary infection with EBV in vivo, suggesting that they are targeted by the virus. EBV enters B cells through CD21, but studies of older children and adults have not shown differences in surface CD21 between naïve B cells and other tonsil B cell populations.

METHODS

In this study, we used an 11-color flow cytometry panel to detail the changes in B cell subpopulations in human tonsils over the first five years of life from 33 healthy US children.

RESULTS

We provide reference ranges for tonsil B cell subpopulations over this age range. We show that the frequency of naïve tonsil B cells decreases over the early years of life, and that naïve B cells expressed higher surface levels of CD21 relative to other tonsil B cell populations.

CONCLUSIONS

We show that young children have a higher frequency of naïve tonsil B cells, and importantly that these cells express increased surface EBV receptor, suggesting that young children have a larger pool of cells that can be infected by the virus. © 2017 International Clinical Cytometry Society.

Early Disseminated Lyme Disease Masquerading as Mononucleosis: A Case Report

BACKGROUND

Disseminated Lyme disease can be difficult to diagnose, as it begins with nonspecific signs and symptoms, which, if not treated correctly, can lead to atrioventricular conduction blocks and meningitis. In addition, the diagnosis can be further complicated by potentially false-positive test results.

CASE REPORT

We report a case of early-disseminated Lyme disease presenting with Borrelia meningitis and concomitant Lyme carditis, which was misdiagnosed as mononucleosis. A young, previously healthy patient had been hiking in the woods of upstate New York and 4 weeks later developed fever, night sweats, and myalgias. He was diagnosed with mononucleosis via a positive rapid heterophile agglutination antibody test to the Epstein-Barr virus at a walk-in clinic and was started on medications, but then subsequently developed left hip pain, a facial droop, and a very long first-degree atrioventricular conduction block. He went to the Emergency Department, where he had testing that confirmed disseminated Lyme disease. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the difficulty in early diagnosis of disseminated Lyme disease and how a potentially false-positive laboratory test can lead to the complications of Borrelia meningitis and Lyme carditis in untreated young healthy patients. Emergency physicians need to consider Lyme disease in patients with nonspecific signs and symptoms, especially if they have been outdoors for prolonged periods of time in Lyme-endemic areas.

Comparison of two automated instruments for Epstein-Barr virus serology in a large adult hospital and implementation of an Epstein-Barr virus nuclear antigen-based testing algorithm

Serology remains the mainstay for diagnosis of Epstein-Barr virus (EBV) infection. This study compared two automated platforms (BioPlex 2200 and Architect i2000SR) to test three EBV serological markers: viral capsid antigen (VCA) immunoglobulins of class M (IgM), VCA immunoglobulins of class G (IgG) and EBV nuclear antigen-1 (EBNA-1) IgG. Using sera from 65 patients at various stages of EBV disease, BioPlex demonstrated near-perfect agreement for all EBV markers compared to a consensus reference. The agreement for Architect was near-perfect for VCA IgG and EBNA-1 IgG, and substantial for VCA IgM despite five equivocal results. Since the majority of testing in our hospital was from adults with EBNA-1 IgG positive results, post-implementation analysis of an EBNA-based algorithm showed advantages over parallel testing of the three serologic markers. This small verification demonstrated that both automated systems for EBV serology had good performance for all EBV markers, and an EBNA-based testing algorithm is ideal for an adult hospital.

Low uric acid level increases the risk of infectious mononucleosis and this effect is more pronounced in women

Infectious mononucleosis (IM) due to Epstein-Barr virus infection is common. Uric acid (UA) is an important endogenous antioxidant. To the best of our knowledge, the association between UA and IM has not been comprehensively investigated to date. The aim of the present study was to investigate this association in Chinese patients. A total of 95 patients (47 men and 48 women) with IM were recruited, along with 95 healthy controls. Clinical data were classified by patient sex. Receiver operating characteristic (ROC) curve analysis was adopted to determine the cut-off values of UA for IM diagnosis and prediction. Crude and adjusted odds ratios (ORs) of UA for IM were analyzed by binary logistic regression. The UA levels were significantly lower in IM patients compared with those in controls. In addition, UA levels in men were significantly higher compared with those in women. The ROC curve demonstrated good diagnostic and predictive values of UA for IM in both sexes. The UA cut-off values were 326.00 and 243.50 µmol/l for diagnosing IM in men and women, respectively, with a diagnostic accuracy of 76.596 and 80.208%, respectively. Binary logistic regression analysis revealed a significant risk of IM in the low UA quartiles in both sexes. Following adjustments, the ORs even increased. Women with low UA levels appeared to be more susceptible to IM. For example, the crude ORs in quartile 1 were 24.000 and 52.500 for men and women, respectively, and the respective adjusted ORs were 31.437 and 301.746 (all P<0.01). To the best of our knowledge, the present study is the first to demonstrate the inverse association between UA and IM, suggesting a progressive decrease of antioxidant reserve in IM. Moreover, low UA was suggestive of IM, particularly in women.

Relapsing EBV encephalitis in a renal transplant recipient

In solid organ transplant recipients, Epstein-Barr virus (EBV) can cause active central nervous system (CNS) infection or malignant transformation of latently infected cells in the CNS, known as post-transplant lymphoproliferative disease (PTLD). Reduction of T-cell immunosuppression is the cornerstone of management. The role of antivirals with in-vitro activity against herpesviruses in EBV-related CNS syndromes is controversial, as they have no effect on latent virus. We report an unusual case of relapsing EBV encephalitis in a donor-positive, EBV-negative renal transplant recipient, with response to valganciclovir. Our report supports the utility of antiviral treatment for EBV encephalitis, as adjunct to reducing immunosuppression, and highlights the need for a systematic approach and long-term, multi-disciplinary follow-up of such patients.

Epstein-Barr virus and cytomegalovirus mononucleosis: Important causes of febrile illness in returned travellers

BACKGROUND

Diagnosing the cause of fever in the returned traveller is challenging. Efforts often focus on identifying 'exotic' pathogens. Primary Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections cause clinical features that overlap with many exotic pathogens. The age-matched seroprevalence of both EBV and CMV is greater in tropical than temperate areas. We describe the clinical and laboratory features of returned travellers diagnosed with primary CMV and EBV syndromes.

METHODS

Patients with laboratory-confirmed primary EBV and CMV infections who had attended the Hospital for Tropical Diseases (HTD), London between 1st October 2011 and 1st October 2016 were identified. Clinical and laboratory data were obtained and analysed.

RESULTS

Twenty-two patients with primary EBV infection and 31 with primary CMV infection were identified. The commonest presenting features of both infections were fever (81.1%), headache (50.9%) and arthralgia/myalgia (49.1%). Cervical lymphadenopathy was seen more frequently with EBV than with CMV (59.1% vs. 25.8%, P = 0.02). Transaminitis (79.2%) and lymphocytosis (52.8%) were the commonest laboratory abnormalities in both groups.

CONCLUSIONS

Primary EBV and CMV infections are important causes of febrile illness in returning travellers. Identification of these pathogens prevents unnecessary, expensive investigations for more 'exotic' pathogens and impacts clinical management for example facilitating prognostication and antimicrobial stewardship.

Infectious mononucleosis-like syndrome with high lymphocytosis and positive IgM EBV and CMV antibodies in a three-year-old girl

Primary Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection usually affects preadolescent children or young adults, causing similar clinical presentation. Signs and symptoms are typically mild, and the majority of clinical and laboratory findings resolve spontaneously within one month after onset. In adulthood, the risk of fulminant EBV infection and severe complications is much higher, which may be related to increasing memory CD8+ T-cell population with age. It is still not clear what exactly triggers T-cell clonal proliferation. Animals model studies on heterologous immunity between viruses revealed that pre-existing memory T-cells may contribute to excessive immune response during subsequent infection with a new, unrelated pathogen. A 3.5-year-old girl was admitted to hospital with a suspicion of lymphoproliferative disorder. Peripheral blood smear revealed a massive lymphocytosis (61,600 cells/µl) with 62% share of atypical lymphocytes. The clinical presentation and positive EBV and CMV IgM test strongly suggested infectious mononucleosis syndrome as a result of EBV and CMV coinfection.

Natural killer cells in herpesvirus infections

Natural killer (NK) cells are potent innate cytotoxic lymphocytes for the destruction of infected and transformed cells. Although they were originally considered to be ready-made assassins after their hematopoietic development, it has recently become clear that their activity is regulated by mechanisms such as repertoire composition, licensing, priming, and adaptive memory-like differentiation. Some of these mechanisms are influenced by infectious disease agents, including herpesviruses. In this review, we will compare expansion, stimulation, and effector functions of NK cell populations after infections with β- and γ ₁-herpesviruses because, though closely related, these pathogens seem to drive completely opposite NK cell responses. The discussed findings suggest that different NK cell subsets expand and perform protective functions during infectious diseases and might be used diagnostically to predict resistance to the causative pathogens as well as treat them by adoptive transfer of the respective populations.