Chronic Active Epstein-Barr Virus Disease

A differential diagnosis method for systemic CAEBV and the prospect of EBV-related immune cell markers via flow cytometry

Chronic active Epstein-Barr virus (CAEBV) infection of the T-cell or Natural killer (NK)-cell type, systemic form (systemic CAEBV or sCAEBV) was defined by the WHO in 2017 as an EBV-related lymphoproliferative disorder and is listed as an EBV-positive T-cell and NK-cell proliferation. The clinical manifestations and prognoses are heterogeneous. This makes systemic CAEBV indistinguishable from other EBV-positive T-cell and NK-cell proliferations. Early diagnosis of systemic CAEBV and early hematopoietic stem cell transplantation can improve patient prognosis. At present, the diagnosis of systemic CAEBV relies mainly on age, clinical manifestations, and cell lineage, incurring missed diagnosis, misdiagnosis, long diagnosis time, and inability to identify high-risk systemic CAEBV early. The diagnostic methods for systemic CAEBV are complicated and lack systematic description. The recent development of diagnostic procedures, including molecular biological and immunological techniques such as flow cytometry, has provided us with the ability to better understand the proliferation of other EBV-positive T cells and NK cells, but there is no definitive review of their value in diagnosing systemic CAEBV. This article summarizes the recent progress in systemic CAEBV differential diagnosis and the prospects of flow cytometry.

Epstein-Barr virus-driven lymphoproliferation in inborn errors of immunity: a diagnostic and therapeutic challenge

INTRODUCTION

Inborn errors of immunity (IEI) are a group of genetically heterogeneous disorders with a wide-ranging clinical phenotype, varying from increased predisposition to infections to dysregulation of the immune system, including autoimmune phenomena, autoinflammatory disorders, lymphoproliferation, and malignancy. Lymphoproliferative disorder (LPD) in IEI refers to the nodal or extra-nodal and persistent or recurrent clonal or non-clonal proliferation of lymphoid cells in the clinical context of an inherited immunodeficiency or immune dysregulation. The Epstein-Barr virus (EBV) plays a significant role in the etiopathogenesis of LPD in IEIs. In patients with specific IEIs, lack of immune surveillance can lead to an uninhibited proliferation of EBV-infected cells that may result in chronic active EBV infection, hemophagocytic lymphohistiocytosis, and LPD, particularly lymphomas.

AREAS COVERED

We intend to discuss the pathogenesis, diagnosis, and treatment modalities directed toward EBV-associated LPD in patients with distinct IEIs.

EXPERT OPINION

EBV-driven lymphoproliferation in IEIs presents a diagnostic and therapeutic problem that necessitates a comprehensive understanding of host-pathogen interactions, immune dysregulation, and personalized treatment approaches. A multidisciplinary approach involving immunologists, hematologists, infectious disease specialists, and geneticists is paramount to addressing the diagnostic and therapeutic challenges posed by this intriguing yet formidable clinical entity.

Clinical Characteristics of Peripheral Lymphocyte Subtypes in Chronic Active Epstein-Barr Virus Infection

BACKGROUND

We aimed to analyze the clinical characteristics of peripheral Epstein-Barr virus (EBV)-infected lymphocyte subtypes in children with chronic active EBV infection (CAEBV).

METHODS

The levels of peripheral EBV infection of CD4+ T cells, CD8+ T cells, and CD56+ natural killer (NK) cells were determined by flow cytometry and quantitative polymerase chain reaction (qPCR) in patients with CAEBV from July 2017 to July 2022.

RESULTS

In total, 112 children with CAEBV were evaluated. Of these, CD4+ type, CD8+ type, and CD56+ type were defined in 44, 21, and 47 patients, respectively. Patients with CD8+ T-cell type had a significantly higher frequency of rash, while hepatomegaly was more common in patients with CD4+ T-cell type. Generally, patients with CD8+ T-cell type had the lowest overall survival rate (P = .017). Patients treated with chemotherapy and hematopoietic stem cell transplantation (HSCT) had a better prognosis (P = .001). In multivariate analysis, rash, hemophagocytic lymphohistiocytosis, CD8+ T-cell type, and no decrease of plasma EBV-DNA after treatment were independent indicators of poor prognosis (P = .002, .024, .022, and .012, respectively).

CONCLUSIONS

In children with CAEBV, rash was more frequent in patients with CD8+ T-cell type, whereas patients with CD4+ T-cell type were more likely to develop hepatomegaly. Patients with CD8+ T-cell type had a poor prognosis despite receiving chemotherapy or further HSCT.

Comprehensive mapping of immune perturbations associated with secondary hemophagocytic lymphohistiocytosis

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a hyperinflammatory syndrome characterized by immune disorders. It is imperative to elucidate the immunophenotypic panorama and the interactions among these cells in patients. Human peripheral blood mononuclear cells were collected from healthy donors and sHLH patients and tested using multicolor flow cytometry. We used FlowSOM to explore and visualize the immunophenotypic characteristics of sHLH. By demonstrating the phenotypes of immune cells, we discovered that sHLH patients had significantly higher levels of CD56+ monocytes, higher levels of myeloid-derived suppressor cells, low-density neutrophil-to-T cell ratio, and higher heterogeneous T cell activation than healthy donors. However, natural killer cell cytotoxicity and function were impaired. We then assessed the correlations among 30 immune cell types and evaluated metabolic analysis. Our findings demonstrated polymorphonuclear myeloid-derived suppressor cells, CD56+ monocytes, and neutrophil-to-T cell ratio were elevated abnormally in sHLH patients, which may indicate an association with immune overactivation and inflammatory response. We are expected to confirm that they are involved in the occurrence of the disease through further in-depth research.

Clinical characteristics and literature review of chronic active Epstein-Barr virus-associated enteritis

Chronic active Epstein-Barr virus (EBV) infection-associated enteritis (CAEAE) in nonimmunodeficient individuals is rare. To report a case of CAEAE, relevant articles were searched through databases. The clinical manifestations, endoscopic findings, strategies of treatment, prognoses, and follow-up results of CAEAE patients were analyzed. Including this report, seven citations in the literature provide descriptions of 27 cases of CAEAE. There were 21 males and six females, with a mean age of 40 years. The main clinical manifestations were fever (25/27), abdominal pain (14/27), diarrhea (16/27), hematochezia or bloody stools (13/27), and decreased hemoglobin and red blood cell counts in routine blood tests (14/27). Elevations in inflammatory markers, white blood cell (WBC) counts, and C-reactive protein (CRP) were common. Coagulation was often abnormal. Histopathology confirmed EBV-encoded small nuclear RNA (EBER) in the affected tissue via in situ hybridization. The average serum EBV DNA load was 6.3 × 10^5 copies/mL. All patients had varying degrees of intestinal ulcers endoscopically, and the ulcers and pathology were uncharacterized and misdiagnosed mostly as inflammatory bowel disease (IBD). The course of the disease was progressive and later complicated by intestinal bleeding, intestinal perforation, septic shock, and a high rate of emergency surgery. However, the conditions of the patients often did not improve after surgery, and some patients soon died due to reperforation or massive hematochezia. Hormone and antiviral treatment had no obvious effect. There was a significant difference in surgical and nonsurgical survival (p < 0.05). The proportion of patients who died within 6 months was as high as 63.6% (7/11). CAEAE belongs to a group of rare, difficult conditions, has an insidious clinical course, has a high case fatality rate, and may later develop into EBV-positive lymphoproliferative disorder (EBV-LPD), which in turn leads to carcinogenesis. Clinicians should raise awareness that in patients with multiple ulcers in the intestine of unknown etiology, attention should be paid to EBV serology, and histology to make the diagnosis as early as possible.

Mitochondrial DNA Missense Mutations ChrMT: 8981A > G and ChrMT: 6268C > T Identified in a Caucasian Female with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Triggered by the Epstein-Barr Virus

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystem disabling disease with unclear etiology and pathophysiology, whose typical symptoms include prolonged debilitating recovery from fatigue or postexertional malaise (PEM). Disrupted production of adenosine triphosphate (ATP), the intracellular energy that fuels cellular activity, is a cause for fatigue. Here, we present a long-term case of ME/CFS: a 75-year-old Caucasian female patient, whose symptoms of ME/CFS were clearly triggered by an acute infection of the Epstein-Barr virus 24 years ago (mononucleosis). Before then, the patient was a healthy professional woman. A recent DNA sequence analysis identified missense variants of mitochondrial respiratory chain enzymes, including ATP6 (ChrMT: 8981A > G; Q152R) and Cox1 (ChrMT: 6268C > T; A122V). Protein subunits ATP6 and Cox1 are encoded by mitochondrial DNA outside of the nucleus: the Cox1 gene encodes subunit 1 of complex IV (CIV: cytochrome c oxidase) and the ATP6 gene encodes subunit A of complex V (CV: ATP synthase). CIV and CV are the last two of five essential enzymes that perform the mitochondrial electron transport respiratory chain reaction to generate ATP. Further analysis of the blood sample using transmission electron microscopy demonstrated abnormal, circulating, extracellular mitochondria. These results indicate that the patient had dysfunctional mitochondria, which may contribute directly to her major symptoms, including PEM and neurological and cognitive changes. Furthermore, the identified variants of ATP6 (ChrMT: 8981A > G; Q152R) and Cox1 (ChrMT: 6268C > T; A122V), functioning at a later stage of mitochondrial ATP production, may play a role in the abnormality of the patient's mitochondria and the development of her ME/CFS symptoms.

Novel plasma microRNA expression features in diagnostic use for Epstein-Barr virus-associated febrile diseases

Background

Epstein-Barr virus (EBV) is widely infected in humans and causes various diseases. Among them, microRNAs of EBV play a key role in the progression of EBV-associated febrile diseases. There're few specific indicators for rapid differential diagnosis of various febrile diseases associated with EBV, and the lack of more reliable screening methods with high diagnostic utility has led to spaces for improvement in the accurate diagnosis and efficient treatment of relevant patients, making EBV infection a complicated clinical problem. With recent advances in plasma microRNA testing, the apparent presence of EBV microRNAs in plasma can help screen for EBV infection. The gene networks targeted by these microRNAs can also indicate potential biomarkers of EBV-associated febrile diseases. This study aimed to identify some novel miRNAs as potential biomarkers for early diagnosis of respectively EBV-associated febrile diseases.

Materials and methods

A total of 110 participants were recruited for this task. First, we performed high-throughput sequencing and preliminary PCR validation of differentially expressed miRNAs in 15 participants with EBV-associated fever (divided into common EBV carriers), infectious mononucleosis (IM) and chronic active EBV infection (CAEBV), EBV-associated Hemophagocytic Lymphohistiocytosis group (EBV-HLH), and 3 healthy individuals. After a comprehensive analysis, 10 miRNAs with abnormal expression were screened, and then qRT-PCR was performed in the rest of 95 participants to detect the validation of miRNAs expression in plasma samples. Thereafter, we further investigated their potential for clinical application in EBV-related febrile diseases by using a combination of Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and Protein-protein interaction network analysis.

Results

Through identification and detailed analysis of the obtained data, we found significant differences in the expression of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p in blood samples from patients with different EBV-related febrile diseases. We found that the expression levels of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p in plasma are indicative of determining different disease types of EBV-related febrile diseases, while EBV-miR-BART22 and EBV-miR-BART2-3p may be potential therapeutic targets.

Conclusion

The expression levels of Hsa-miR-320d, EBV-miR-BART22, and EBV-miR-BART2-3p suggest that they may be used as transcriptional features for early differential diagnosis of EBV-related febrile diseases, and EBV-miR-BART22 and EBV-miR-BART2-3p may be potential therapeutic targets.

Asymptomatic viruses detectable in saliva in the first year of life: a narrative review

Viral infections are common in children. Many can be asymptomatic or have delayed health consequences. In view of increasing availability of point-of-care viral detection technologies, with possible application in newborn screening, this review aimed to (1) identify potentially asymptomatic viruses detectable in infants under one year old, via saliva/nasopharyngeal swab, and (2) describe associations between viruses and long-term health conditions. We systematically searched Embase(Ovid), Medline(Ovid) and PubMed, then further searched the literature in a tiered approach. From the 143 articles included, 28 potentially asymptomatic viruses were identified. Our second search revealed associations with a range of delayed health conditions, with most related to the severity of initial symptoms. Many respiratory viruses were linked with development of recurrent wheeze or asthma. Of note, some potentially asymptomatic viruses are linked with later non-communicable diseases: adenovirus serotype 36 and obesity, Enterovirus-A71 associated Hand, Foot, Mouth Disease and Attention-Deficit Hyperactivity Disorder, Ebstein Barr Virus (EBV) and malignancy, EBV and multiple sclerosis, HHV-6 and epilepsy, HBoV-1 and lung fibrosis and Norovirus and functional gastrointestinal disorders. Our review identified many potentially asymptomatic viruses, detectable in early life with potential delayed health consequences, that could be important to screen for in the future using rapid point-of-care viral detection methods. IMPACT: Novel point-of-care viral detection technologies enable rapid detection of viruses, both old and emerging. In view of increasing capability to screen for viruses, this is the first review to explore which potentially asymptomatic viruses, that are detectable using saliva and/or nasopharyngeal swabs in infants less than one year of age, are associated with delayed adverse health conditions. Further research into detecting such viruses in early life and their delayed health outcomes may pave new ways to prevent non-communicable diseases in the future.

Updated guidelines for chronic active Epstein-Barr virus disease

Chronic active Epstein-Barr virus disease (CAEBV), formerly named chronic active Epstein-Barr virus infection, is characterized by systemic inflammation and clonal proliferation of Epstein-Barr virus (EBV)-infected T or NK cells. As CAEBV is a potentially life-threatening illness, appropriate diagnosis and therapeutic interventions are necessary for favorable clinical outcomes. Substantial evidence regarding the pathogenesis and treatment of CAEBV has been accumulated since previous guidelines for the diagnosis of CAEBV were proposed. To reflect this evidence, we updated the guidelines for the diagnosis and treatment of CAEBV to improve clinical management of the disease. The details of the updated guidelines are presented in this report. Diagnosis of CAEBV now requires confirmation of a high copy number of EBV genome and EBV-infected T or NK cells. An EBV DNA load ≥ 10,000 IU/mL in whole blood is proposed as the diagnostic cutoff value for CAEBV in this updated guideline. A standard treatment approach for CAEBV has not been established, and hematopoietic stem cell transplantation (HSCT) is considered the only curative treatment. Chemotherapy can be administered to control disease activity before HSCT.

A comparison of the International Consensus and 5th WHO classifications of T-cell lymphomas and histiocytic/dendritic cell tumours

Since the publication in 2017 of the revised 4th Edition of the World Health Organization (WHO) classification of haematolymphoid tumours, here referred to as WHO-HAEM4, significant clinicopathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining the diagnostic criteria of several diseases, upgrading entities previously defined as provisional and identifying new entities. This process has resulted in two recent classification proposals of lymphoid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, focusing on T-cell lymphomas and histiocytic/dendritic cell tumours. Moreover, we update the genetic data of the various pathological entities. The main goal is to provide a tool to facilitate the work of the pathologists, haematologists and researchers involved in the diagnosis and treatment of these haematological malignancies.

Epstein-Barr virus infection: the micro and macro worlds

Epstein‒Barr virus (EBV) is a DNA virus that belongs to the human B lymphotropic herpesvirus family and is highly prevalent in the human population. Once infected, a host can experience latent infection because EBV evades the immune system, leading to hosts harboring the virus for their lifetime. EBV is associated with many diseases and causes significant challenges to human health. This review first offers a description of the natural history of EBV infection, clarifies the interaction between EBV and the immune system, and finally focuses on several major types of diseases caused by EBV infection.

A Comparison of the Fifth World Health Organization and the International Consensus Classifications of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare subset of non-Hodgkin lymphomas that often carry significant difficulty in diagnosis and classification because of their rarity and biological complexity. Previous editions of the World Health Organization (WHO) classifications of hemopoietic neoplasms in 2001, 2008, and 2017 aimed to standardize hemopoietic neoplasm diagnosis in general. Since then, crucial clinico-pathological, immunophenotypic, and recent molecular discoveries have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, upgrading entities previously defined as provisional, and identifying new entities. In 2022, two different models were proposed to classify hematolymphoid neoplasms: the 5th edition of the WHO classification (WHO-HAEM5) and the International Consensus Classification (ICC). Of note, a common nosography is mandatory to ensure progress in health science and ensure the basis for a real precision medicine. In this article, the authors summarized the main differences with the previous fourth WHO edition and reviewed the main discrepancies between the two newest classifications, as far as PTCLs are concerned.

The variant landscape and function of DDX3X in cancer and neurodevelopmental disorders

RNA molecules rely on proteins across their life cycle. DDX3X encodes an X-linked DEAD-box RNA helicase with a Y-linked paralog, DDX3Y. DDX3X is central to the RNA life cycle and is implicated in many conditions, including cancer and the neurodevelopmental disorder DDX3X syndrome. DDX3X-linked conditions often exhibit sex differences, possibly due to differences between expression or function of the X- and Y-linked paralogs DDX3X and DDX3Y. DDX3X-related diseases have different mutational landscapes, indicating different roles of DDX3X. Understanding the role of DDX3X in normal and disease states will inform the understanding of DDX3X in disease. We review the function of DDX3X and DDX3Y, discuss how mutation type and sex bias contribute to human diseases involving DDX3X, and review possible DDX3X-targeting treatments.

Utility of clinical metagenomics in diagnosing malignancies in a cohort of patients with Epstein-Barr virus positivity

Backgrounds

Differentiation between benign and malignant diseases in EBV-positive patients poses a significant challenge due to the lack of efficient diagnostic tools. Metagenomic Next-Generation Sequencing (mNGS) is commonly used to identify pathogens of patients with fevers of unknown-origin (FUO). Recent studies have extended the application of Next-Generation Sequencing (NGS) in identifying tumors in body fluids and cerebrospinal fluids. In light of these, we conducted this study to develop and apply metagenomic methods to validate their role in identifying EBV-associated malignant disease.

Methods

We enrolled 29 patients with positive EBV results in the cohort of FUO in the Department of Infectious Diseases of Huashan Hospital affiliated with Fudan University from 2018 to 2019. Upon enrollment, these patients were grouped for benign diseases, CAEBV, and malignant diseases according to their final diagnosis, and CNV analysis was retrospectively performed in 2022 using samples from 2018 to 2019.

Results

Among the 29 patients. 16 of them were diagnosed with benign diseases, 3 patients were diagnosed with CAEBV and 10 patients were with malignant diseases. 29 blood samples from 29 patients were tested for mNGS. Among all 10 patients with malignant diagnosis, CNV analysis suggested neoplasms in 9 patients. Of all 19 patients with benign or CAEBV diagnosis, 2 patients showed abnormal CNV results. The sensitivity and specificity of CNV analysis for the identification for tumors were 90% and 89.5%, separately.

Conclusions

The application of mNGS could assist in the identification of microbial infection and malignancies in EBV-related diseases. Our results demonstrate that CNV detection through mNGS is faster compared to conventional oncology tests. Moreover, the convenient collection of peripheral blood samples adds to the advantages of this approach.

Epstein-Barr virus-associated B-cell lymphoproliferative disorder meeting the definition of CAEBV B cell disease: a case report

BACKGROUND

Chronic active Epstein-Barr virus infection (CAEBV) is a systemic EBV-positive lymphoproliferative disorder (EBV-LPD) considered to be associated with a genetic immunological abnormality, although its cause is still unclear. EBV is usually detected in T cells or NK cells in CAEBV patients with only a few cases involving B cells described in East Asia, which may be due to differences in genetic and environmental factors.

CASE DESCRIPTION

A 16-year-old boy who seemed to be diagnosed as CAEBV of B cell type was studied. The patient had IM-like symptoms persisting for more than 3 months, high levels of EBV DNA in the PB, and positive EBER in situ hybridization in B cells. In addition, to exclude underlying genetic disorders, we performed next-generation sequencing (NGS) and whole-exome sequencing (WES), which identified the missense mutation in PIK3CD (E1021K), ADA (S85L) and CD3D (Q140K) in the patient while no same genetic mutation was detected in his parents and sister. However, there is no diagnosis of CAEBV of B cell type in the most recent World Health Organization classification of tumors of hematopoietic and lymphoid tissues, therefore we finally diagnosed this patient as EBV-B-LPD.

CONCLUSIONS

This study shows a rare case of a patient meeting the definition of CAEBV B-cell disease in East Asia. Meanwhile, the case indicates that the missense mutation and the disease are related.

Fas/FasL and Complement Activation are Associated with Chronic Active Epstein-Barr Virus Hepatitis

BACKGROUND AND AIMS

Chronic active Epstein-Barr virus hepatitis (CAEBVH) is a rare and highly lethal disease characterized by hepatitis and hepatomegaly. This study aimed to investigate the clinicopathological features and pathogenic mechanisms of CAEBVH.

METHODS

Ten patients with confirmed Epstein-Barr virus hepatitis infection were enrolled. The clinicopathological characteristics of these patients were summarized and analyzed. Flow cytometry was utilized to detect peripheral blood immune cell phenotypes and whole exome sequencing was used to explore pathogenic genetic mechanisms. Lastly, immunohistochemical staining was employed to verify pathogenic mechanisms.

RESULTS

Clinical features observed in all Epstein-Barr virus hepatitis patients included fever (7/10), splenomegaly (10/10), hepatomegaly (9/10), abnormal liver function (8/10), and CD8⁺ T cell lymphopenia (6/7). Hematoxylin and eosin staining revealed lymphocytic infiltration in the liver. Positive Epstein-Barr virus-encoded small RNA in-situ hybridization (EBER-ISH) of lymphocytes of liver tissues was noted. Whole exome sequencing indicated that cytotoxic T lymphocytes and the complement system were involved. The expression of CD8, Fas, FasL, and Caspase-8 expression as well as apoptotic markers was enhanced in the Epstein-Barr virus hepatitis group relative to the controls (p<0.05). Lastly, Complement 1q and complement 3d expression, were higher in CAEBVH patients relative to controls (p<0.05).

CONCLUSIONS

CAEBVH patients developed fever, hepatosplenomegaly, and lymphadenopathy. Histopathological changes were a diffuse lymphocytic sinusoidal infiltrate with EBER-ISH positivity. Fas/FasL and complement activation were involved in CAEBVH patients.

Chronic Active Epstein-Barr Virus (EBV) Infection Controlled by Allogeneic Stem Cell Transplantation and EBV-Specific T Cells

We report sustained remission of chronic active Epstein-Barr virus (EBV) infection in a 27-year-old female patient treated with third-party EBV-specific T cells followed by allogeneic hematopoietic stem cell transplantation (HSCT). The viremia cleared after administration of anti-T-lymphocyte globulin for graft-versus-host disease (GvHD) prophylaxis. Subsequent expansion of EBV-infected host T cells was controlled by transfusion of donor-derived EBV-specific T cells.

T cell-mediated immunity during Epstein-Barr virus infections in children

Epstein-Barr virus (EBV) infection is extremely common worldwide, with approximately 90% of adults testing positive for EBV antibodies. Human are susceptible to EBV infection, and primary EBV infection typically occurs early in life. EBV infection can cause infectious mononucleosis (IM) as well as some severe non-neoplastic diseases, such as chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), which can have a heavy disease burden. After primary EBV infection, individuals develop robust EBV-specific T cell immune responses, with EBV-specific CD8⁺ and part of CD4⁺ T cells functioning as cytotoxic T cells, defending against virus. Different proteins expressed during EBV's lytic replication and latent proliferation can cause varying degrees of cellular immune responses. Strong T cell immunity plays a key role in controlling infection by decreasing viral load and eliminating infected cells. However, the virus persists as latent infection in EBV healthy carriers even with robust T cell immune response. When reactivated, it undergoes lytic replication and then transmits virions to a new host. Currently, the relationship between the pathogenesis of lymphoproliferative diseases and the adaptive immune system is still not fully clarified and needs to be explored in the future. Investigating the T cell immune responses evoked by EBV and utilizing this knowledge to design promising prophylactic vaccines are urgent issues for future research due to the importance of T cell immunity.

An update on genetic aberrations in T-cell neoplasms

T-cell neoplasms are a highly heterogeneous group of leukaemias and lymphomas that represent 10-15% of all lymphoid neoplasms. Traditionally, our understanding of T-cell leukaemias and lymphomas has lagged behind that of B-cell neoplasms, in part due to their rarity. However, recent advances in our understanding of T-cell differentiation, based on gene expression and mutation profiling and other high throughput methods, have better elucidated the pathogenetic mechanisms of T-cell leukaemias and lymphomas. In this review, we provide an overview of many of the molecular abnormalities that occur in various types of T-cell leukaemia and lymphoma. Much of this knowledge has been used to refine diagnostic criteria that has been included in the fifth edition of the World Health Organization. This knowledge is also being used to improve prognostication and identify novel therapeutic targets, and we expect this progress will continue, eventually resulting in improved outcomes for patients with T-cell leukaemias and lymphomas.

When to suspect inborn errors of immunity in Epstein-Barr virus-related lymphoproliferative disorders

BACKGROUND

More than 95% of humans have been infected with Epstein-Barr virus (EBV) and develop anti-EBV IgG antibodies, conferring immunity. However, among specific populations, EBV may induce a range of B-cell lymphoproliferative disorders (LPDs). EBV may also contribute to T-cell and natural killer (NK)-cell lymphoproliferation. The immune system is essential to prevent infection and development of cancer. Inborn errors of immunity (IEIs) are a heterogenous group of more than 450 genetic disorders predisposing to severe and/or recurrent infection, autoimmunity, autoinflammation, or early-onset/severe neoplasia or lymphoproliferation. Monogenic disorders of T-cell and B-cell signalling are classic IEIs that predispose to EBV-associated LPDs.

OBJECTIVES

We aimed to outline the various clinical manifestations of EBV-associated LPDs and the underlying IEIs associated with such presentations and discuss the recommended management and therapeutic options pertaining to these disorders.

SOURCES

We searched PubMed, Embase, and Web of Science Core Collection on 30 September 2021. Clinical studies, systematic reviews, narrative reviews, and case reports were identified through search strategy and cross reference from primary literature.

CONTENT

Effective T-cell and NK-cell cytotoxicity towards EBV-infected B cells relies on intact MAGT1-dependent NKG2D pathways and signalling lymphocyte activation molecular-associated protein-dependent signalling lymphocyte activation molecular receptors. The interaction between CD27 and CD70 is also critical to drive the expansion of EBV-specific T cells. IEIs due to T-cell and B-cell signalling defects and/or impaired T-cell and NK-cell cytotoxicity predispose to EBV-related lymphoproliferation. This includes classic disorders such as X-linked lymphoproliferative disease 1 (due to SH2D1A mutations), X-linked lymphoproliferative disease 2 (XIAP), and other genetic diseases, such as ITK, MAGT1, CD27, CD70, CTPS1, RASGRP1, and CORO1A deficiencies. EBV-driven lymphoproliferation may manifest to a lesser degree in MST1/STK4, DOCK8, STIM1, CORO1A, IL21R, PIK3CD gain-of-function, and PI3KR1 deficiencies.

IMPLICATIONS

Early screening for IEIs is indicated in cases of EBV-related lymphoproliferation because different forms of IEIs have specific prognostic and therapeutic implications.

The innate and T-cell mediated immune response during acute and chronic gammaherpesvirus infection

Immediately after entry into host cells, viruses are sensed by the innate immune system, leading to the activation of innate antiviral effector mechanisms including the type I interferon (IFN) response and natural killer (NK) cells. This innate immune response helps to shape an effective adaptive T cell immune response mediated by cytotoxic T cells and CD4+ T helper cells and is also critical for the maintenance of protective T cells during chronic infection. The human gammaherpesvirus Epstein-Barr virus (EBV) is a highly prevalent lymphotropic oncovirus that establishes chronic lifelong infections in the vast majority of the adult population. Although acute EBV infection is controlled in an immunocompetent host, chronic EBV infection can lead to severe complications in immunosuppressed patients. Given that EBV is strictly host-specific, its murine homolog murid herpesvirus 4 or MHV68 is a widely used model to obtain in vivo insights into the interaction between gammaherpesviruses and their host. Despite the fact that EBV and MHV68 have developed strategies to evade the innate and adaptive immune response, innate antiviral effector mechanisms still play a vital role in not only controlling the acute infection but also shaping an efficient long-lasting adaptive immune response. Here, we summarize the current knowledge about the innate immune response mediated by the type I IFN system and NK cells, and the adaptive T cell-mediated response during EBV and MHV68 infection. Investigating the fine-tuned interplay between the innate immune and T cell response will provide valuable insights which may be exploited to design better therapeutic strategies to vanquish chronic herpesviral infection.

Outcomes of programmed death protein-1 inhibitors treatment of chronic active Epstein Barr virus infection: A single center retrospective analysis

Introduction

Chronic active Epstein-Barr virus (CAEBV) disease is a high-mortality disease, which is characterized by persistent infectious mononucleosis-like symptoms. There is no standard treatment for CAEBV and allogeneic hematopoietic stem cell transplantation (HSCT) was considered the only potentially therapeutic approach. PD-1 inhibitors have achieved high response in many Epstein-Barr virus-related diseases. In this single-center retrospective analysis, we report the outcomes of PD-1 inhibitors treatment of CAEBV.

Methods

All CAEBV patients without hemophagocytic lymphohistiocytosis (HLH), who were treated with PD-1 inhibitors in our center between 6/1/2017 and 12/31/2021, were retrospectively analyzed. The efficacy and safety of the PD-1 inhibitors were evaluated.

Results

Among the sixteen patients with a median age at onset of 33 years (range, 11-67 years), twelve patients responded to PD-1 inhibitors and the median progression-free survival (PFS) was 11.1 months (range, 4.9-54.8 months). Three achieved clinical complete response (clinical CR), as well as molecular CR. Five patients achieved and remained partial response (PR), and four converted from PR to no response (NR). For three CR patients, the median time and cycles from the first application of PD-1 inhibitor to clinical CR were 6 weeks (range, 4-10 weeks) and 3 cycles (range, 2-4 cycles), and molecular CR was achieved after a median of 16.7 weeks (range, 6.1-18.4 weeks) and 5 cycles (range, 3-6 cycles) of PD-1 inhibitor infusion. No immune-related adverse events have been observed except for one patient who suffered immune-related pancreatitis. There was no correlation of treatment outcome with blood count, liver function, LDH, cytokine or ferritin levels. NK cell function, PD-L1 expression in tumor tissue and gene mutation possibly correlated with treatment response.

Discussion

In patients with CAEBV, PD-1 inhibitors have tolerable toxicity and comparable outcomes while improving quality of life and financial toxicity. Larger prospective studies and longer follow-up time is needed to be conducted.

Biopathology of childhood, adolescent and young adult non-Hodgkin lymphoma

Mature non-Hodgkin lymphomas (NHL) in the childhood, adolescent and young adult (CAYA) population are rare and exhibit unique clinical, immunophenotypic and genetic characteristics. Application of large-scale unbiased genomic and proteomic technologies such as gene expression profiling and next generation sequencing (NGS) have led to enhanced understanding of the genetic basis for many lymphomas in adults. However, studies to investigate the pathogenetic events in CAYA population are relatively sparse. Enhanced understanding of the pathobiologic mechanisms involved in non-Hodgkin lymphomas in this unique population will allow for improved recognition of these rare lymphomas. Elucidation of the pathobiologic differences between CAYA and adult lymphomas will also lead to the design of more rational and much needed, less toxic therapies for this population. In this review, we summarize recent insights gained from the proceedings of the recent 7th International CAYA NHL Symposium held in New York City, New York October 20-23, 2022.

How I Diagnose EBV-Positive B- and T-Cell Lymphoproliferative Disorders

OBJECTIVES

Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) encompass a group of well-defined entities of B-, T-, and natural killer (NK)-cell derivation. The diagnosis of these disorders is challenging because of clinical and morphologic features that may overlap with other benign and malignant EBV+ lymphoproliferations. This review describes our approach to the diagnosis of EBV-associated LPDs.

METHODS

Two cases are presented that illustrate how we diagnose EBV-associated LPDs. The first case represents a systemic EBV+ T-cell lymphoma of childhood and the second case an EBV+ mucocutaneous ulcer. The clinicopathologic features that help distinguish these entities from biological and morphologic mimickers are emphasized.

RESULTS

The accurate diagnosis of EBV-associated LPDs requires the incorporation of histologic and immunophenotypic features, the assessment of the EBV latency program, and, most important, complete clinical findings. Clonality analysis is not helpful in distinguishing benign from malignant EBV+ LPDs.

CONCLUSIONS

The better understanding of EBV-associated LPDs has resulted in the recognition of well-defined entities of B-, T-, and NK-cell derivation and consequently improvement of their treatment with curative intent. It is critical to distinguish benign from malignant EBV+ LPDs to avoid overtreatment.

Chronic Active Epstein-Barr Virus Infection With Central Nervous System Involvement in Children: A Clinical Study of 22 Cases

OBJECTIVE

To analyze the clinical features, treatment, and prognosis of chronic active Epstein-Barr virus infection (CAEBV) with central nervous system (CNS) involvement in children.

METHODS

Patients with CAEBV admitted to Beijing Children's Hospital, Capital Medical University, were enrolled in this study from January 2017 to December 2020. They were divided into a CNS group and a non-CNS group based on the presence of CNS involvement.

RESULTS

Twenty-two patients developed CNS disease, accounting for 23.9% (22/92) of CAEBV patients in the same period. Of these, only 2 of 22 patients presented initially with neurologic symptoms in the CNS group, and they all improved after treatment. Cerebrospinal fluid (CSF) examination demonstrated normal protein concentration and cell number in all patients with CNS involvement. Only 7 patients were positive for CSF EBV-DNA. Twenty-one patients had neuroimaging abnormalities, such as white matter signal abnormalities, encephalography or calcification. In the CNS group, 7 (31.8%) patients died, including 5 who died of active hemophagocytic lymphohistiocytosis, 1 died of unrelated causes, and 1 died of respiratory failure caused by pulmonary lymphoproliferative disease progression after transplantation. The 3-year overall survival was lower in the CNS group than in the non-CNS group (63.6% ± 11.9% versus 86.9% ± 4.1%, P = 0.027). Hemophagocytic lymphohistiocytosis (HLH) is an independent risk factor for CNS involvement in patients with CAEBV (OR = 2.946, 95% CI: 1.042-8.335, P = 0.042). Compared with the non-CNS group, blood EBV-DNA loads and CD4+/CD8+ ratio of T lymphocytes in the CNS group were higher (P < 0.001), while fibrinogen levels and natural killer (NK)-cell activity were lower (P = 0.047). Children with CAEBV were more likely to develop CNS diseases with low NK-cell activity (NK-cell activity < 14.00%, P = 0.023) or high alanine aminotransferase (ALT) levels (ALT levels > 40 U/L, P = 0.032).

CONCLUSION

CAEBV with CNS involvement has nonspecific clinical manifestations, laboratory data, neuroimaging but has a worse prognosis. Blood fibrinogen levels and NK-cell activity in CAEBV children with CNS involvement are lower than in those without CNS involvement. In contrast, blood EBV-DNA loads and CD4+/CD8+ ratio of T lymphocytes are higher. Children with CAEBV who presented with HLH, NK-cell activity <14.00%, serum ALT >40 U/L and high-blood EBV-DNA loads are prone to develop CNS diseases.

Immune checkpoints in T cells during oncogenic γ-herpesvirus infections

Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) are two persistent oncogenic γ-herpesviruses with an exclusive tropism for humans. They cause cancers of lymphocyte, epithelial and endothelial cell origin, such as Burkitt's and Hodgkin's lymphoma, primary effusion lymphoma, nasopharyngeal carcinoma, and Kaposi sarcoma. Mutations in immune-related genes but also adverse events during immune checkpoint inhibition in cancer patients have revealed molecular requirements for immune control of EBV and KSHV. These include costimulatory and coinhibitory receptors on T cells that are currently explored or already therapeutically targeted in tumor patients. This review discusses these co-receptors and their influence on EBV- and KSHV-associated diseases. The respective studies reveal surprising specificities of some of these receptors for immunity to these tumor viruses, benefits of their blockade for some but not other virus-associated diseases, and that EBV- and KSHV-specific immune control should be monitored during immune checkpoint inhibition to prevent adverse events that might be associated with their reactivation during treatment.

Epstein-Barr virus and multiple sclerosis

Epstein-Barr virus (EBV) is a ubiquitous human lymphotropic herpesvirus with a well-established causal role in several cancers. Recent studies have provided compelling epidemiological and mechanistic evidence for a causal role of EBV in multiple sclerosis (MS). MS is the most prevalent chronic inflammatory and neurodegenerative disease of the central nervous system and is thought to be triggered in genetically predisposed individuals by an infectious agent, with EBV as the lead candidate. How a ubiquitous virus that typically leads to benign latent infections can promote cancer and autoimmune disease in at-risk populations is not fully understood. Here we review the evidence that EBV is a causal agent for MS and how various risk factors may affect EBV infection and immune control. We focus on EBV contributing to MS through reprogramming of latently infected B lymphocytes and the chronic presentation of viral antigens as a potential source of autoreactivity through molecular mimicry. We consider how knowledge of EBV-associated cancers may be instructive for understanding the role of EBV in MS and discuss the potential for therapies that target EBV to treat MS.

Urgency and necessity of Epstein-Barr virus prophylactic vaccines

Epstein-Barr virus (EBV), a γ-herpesvirus, is the first identified oncogenic virus, which establishes permanent infection in humans. EBV causes infectious mononucleosis and is also tightly linked to many malignant diseases. Various vaccine formulations underwent testing in different animals or in humans. However, none of them was able to prevent EBV infection and no vaccine has been approved to date. Current efforts focus on antigen selection, combination, and design to improve the efficacy of vaccines. EBV glycoproteins such as gH/gL, gp42, and gB show excellent immunogenicity in preclinical studies compared to the previously favored gp350 antigen. Combinations of multiple EBV proteins in various vaccine designs become more attractive approaches considering the complex life cycle and complicated infection mechanisms of EBV. Besides, rationally designed vaccines such as virus-like particles (VLPs) and protein scaffold-based vaccines elicited more potent immune responses than soluble antigens. In addition, humanized mice, rabbits, as well as nonhuman primates that can be infected by EBV significantly aid vaccine development. Innovative vaccine design approaches, including polymer-based nanoparticles, the development of effective adjuvants, and antibody-guided vaccine design, will further enhance the immunogenicity of vaccine candidates. In this review, we will summarize (i) the disease burden caused by EBV and the necessity of developing an EBV vaccine; (ii) previous EBV vaccine studies and available animal models; (iii) future trends of EBV vaccines, including activation of cellular immune responses, novel immunogen design, heterologous prime-boost approach, induction of mucosal immunity, application of nanoparticle delivery system, and modern adjuvant development.

Post-transplant cyclophosphamide for GVHD prophylaxis in pediatrics with chronic active Epstein-Barr virus infection after haplo-HSCT

BACKGROUND

Chronic active Epstein-Barr virus infection (CAEBV) is a rare but life-threatening progressive disease. Human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is the best choice as sometimes HLA-matched donor is not accessible. However, graft-versus-host-disease (GVHD) following transplantation remains a major cause of treatment failure and elevated mortality. Post-transplant cyclophosphamide (PTCy) has recently emerged for effective GVHD prophylaxis in a haploidentical setting in many hematologic malignancies. Here, we report the performance of PTCy for GVHD prophylaxis in a series of CEABV patients treated with haplo-HSCT.

METHODS

Consecutive pediatric CAEBV patients who were treated with haplo-HSCT and give PTCy for GVHD prophylaxis were analyzed. 1-year GVHD and relapse-free survival (GRFS), overall survival (OS) and cumulative incidence of moderate-to-severe chronic GVHD (cGVHD) were estimated.

RESULTS

A total of 8 patients ranging from 2 to 15 years old were included. Among them, 4 patients had early complications after haplo-HSCT. Counts of T-cell subsets increased within 6 months post transplantation, indicating an immune reconstitution. Only 1 patient developed grade II acute GVHD, and 2 patients had moderate cGVHD. One patient died from diffuse alveolar hemorrhage within the first year after transplantation. The 1-year GRFS rate, OS rate and cumulative incidence of moderate-to-severe cGVHD were 62.5%, 87.5% and 25.0%, respectively.

CONCLUSION

Our findings suggest that, among CAEBV patients treated with haplo-HSCT, PTCy may be an alternative choice for the prevention of GVHD.

Impact of Epstein-Barr virus infection in patients with inflammatory bowel disease

A high prevalence of Epstein-Barr virus (EBV) infection in patients with inflammatory bowel disease (IBD) has been reported in many case reports and studies; thus, the association between EBV and IBD has gained increasing attention. Patients with IBD are at an increased risk of opportunistic EBV infection owing to the common use of immunomodulators. EBV infection in IBD patients can cause various complications, including superimposed viral colitis, which is associated with chronicity, exacerbation, and poor prognosis of refractory IBD, and can induce progression to lymphoproliferative disorders, such as EBV-positive mucocutaneous ulcer (EBVMCU), lymphomatoid granulomatosis (LYG), hemophagocytic lymphohistiocytosis (HLH) and diffuse large B-cell lymphoma (DLBCL). It has been suggested to screen for EBV before initiating immunosuppressive therapy and monitor the status of EBV infection in patients with IBD, especially those who are EBV-seronegative and have a risk of primary EBV infection. Clinicians should also be careful of misdiagnosing IBD and EBV-associated lymphoproliferative diseases due to similarities in both clinical symptoms and endoscopic manifestations. Withdrawal of immunosuppressants has been shown to be an effective strategy to achieve remission of disease at the time of EBV diagnosis, but antiviral therapy remains controversial. The present review aims to describe the characteristics of the complications caused by EBV infection and generalize the recent research progress on and challenges caused by EBV infection in IBD patients. The literature for writing this review was collected from 'PubMed' research engine. The keywords 'inflammatory bowel disease and Epstein-Barr virus' or 'ulcerative colitis and Epstein-Barr virus' or 'Crohn's disease and Epstein-Barr virus' were used to collect the literature and relevant papers were collected to help writing this review.

Case report: Systemic muscle involvement as the primary clinical manifestation of chronic active Epstein–Barr virus infection: A case-based review

Chronic active Epstein–Barr virus infection (CAEBV) is common in Asian countries and characterized by recurrent or persistent infectious mononucleosis-like symptoms. Here, we describe a rare case of CAEBV-associated generalized myositis with extranodal NK/T-cell lymphoma, who initially presented with swelling and muscle soreness in the extremities and was diagnosed as polymyositis at the initial stage. CAEBV-associated generalized myositis is different from polymyositis and other types of myositis. Furthermore, it is prone to lymphoma with poor prognosis.

A Lethal Manifestation of Chronic Active Epstein-Barr Virus Infection: A Case Report

Chronic active Epstein-Barr virus infection (CAEBV) is a rare and lethal condition caused by persistent Epstein-Barr virus (EBV) infection. Signs and symptoms of CAEBV infection include fever, lymphadenopathy, and hepatosplenomegaly. Due to life-threatening consequences such as multiple organ failure, hemophagocytic syndrome, EBV-positive lymphoproliferative illness, and coagulopathy, early identification is important for successful therapy. However, because of the wide range of clinical symptoms, it might be difficult to diagnose the disease due to limited clinical experience and a low number of reports. We report a case of CAEBV in a 59-year-old woman from Saudi Arabia. We present the hospital course of the patient from admission until the patient's death as well as the clinical and pathological findings with a review of the literature. This is a rare case of CAEBV in Saudi Arabia.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Chronic active Epstein-Barr exacerbated by COVID-19 co-infection

A 60-year-old Hispanic female was admitted with recurrent fevers, altered mental status, lymphadenopathy, hepatosplenomegaly, and pancytopenia. Initially, sepsis was presumed because of recurrent urinary tract infection with extended-spectrum beta-lactamase Escherichia coli. Despite appropriate therapy, her clinical condition continued to decline. An extensive workup was obtained to determine the source of her ailments. Bone marrow biopsy was negative for leukemia, lymphoma, and myelodysplastic syndrome; fluorescence in situ hybridization and a cytogenetic panel were normal; a lumbar puncture was negative. However, peripheral blood was remarkable for elevated titers for Epstein-Barr virus (EBV) consistent with chronic active EBV. Treatment with valganciclovir showed early positive results, but the patient became co-infected with COVID-19, and her EBV titer increased again, resulting in a precipitous health decline and death.

A rare B-cell type chronic active Epstein-Barr virus infection patient mimicking lymphoma on 18F-FDG PET/CT and literature review

A 13-year-old girl suffered from worsen snoring and persistent bilateral nasal congestion for one year. Paranasal sinus computed tomography (CT) and magnetic resonance imaging (MRI) found nasopharyngeal passages and sinus were occupied with soft tissues and bilateral neck enlarged lymph nodes 6 months ago. Tumor markers were normal. The titers of anti-Epstein-Barr virus (EBV) IgM, anti-EBV IgG, early antigen (EA) IgG, and Epstein-Barr nuclear antigen (EBNA) IgG increased. 2-Deoxy-2-[fluorine-18]-fluoro-D-glucose (¹⁸F-FDG) positron emission tomography combined with CT (PET/CT) revealed thickened soft tissues in nasopharynx and oropharynx, enlarged multiple lymph nodes in the neck, bilateral armpits, abdominal cavity and retroperitoneum, and pelvic cavity, diffuse thickening of the gastric wall of the antrum with hypermetabolism. According to the age, situation, regions, and abnormal FDG uptake, an initial diagnosis of EBV-related lymphoma was made. However, the pathological results of the nasopharyngeal mass and the abdominal lymph node confirmed the final diagnosis of a B-cell type chronic active Epstein-Barr virus disease (CAEBV), a rare type of EBV associated lymphoproliferative disorder (LPD). After receiving adoptive immune cells therapy, the EBV load decreased. At present, the patient is being followed up.

Multisystem T-cell Chronic Active Epstein-Barr Virus Infection: From the Eye to the Kidney

Chronic active Epstein-Barr virus (CAEBV) infection is usually a fatal disease associated with clonal proliferation of EBV-infected T or NK cells. We present the case of a 33-year-old Peruvian patient who developed a multisystem CAEBV, notably responsible for exceptional ophthalmological and renal damage. We describe the clinicopathological features of EBV-induced lymphoproliferative disorder.

Epidemiological characteristics and disease burden of infectious mononucleosis in hospitalized children in the mainland of China: a nationwide retrospective study

Epstein-Barr virus (EBV) is very common, with the infection rate in adults over 90% worldwide. Infectious mononucleosis (IM) is caused by primary infection with EBV. Most IM patients are generally considered to have a favorable prognosis, but a few patients will also develop complications. Children with severe symptoms will require hospitalization. However, the disease burden of children hospitalized with IM in China has been rarely described. In this study, we included the Face sheets of discharge medical records from 27 member children's hospitals of Futang Research Center of Pediatric Development from Jan 1^st, 2016 to Dec 31^st, 2020, and medical information such as gender, age, region, time of admission, length of stay and expenditure were extracted. There are 24,120 IM cases, which accounted for 0.42% (24,120/5,693,262) of all hospitalized cases during this period. The ratio of male to female was 1.48:1. Hospitalization for IM in the 4-6 y age group was the highest among inpatients of all age groups. Case numbers increased year by year between 2016 to 2020, and the monthly hospitalization was generally high from Jul to Sep but reduced from Jan to Feb per year. Bronchitis/pneumonia and hepatic dysfunction are two common complications in hospitalized IM patients. The median length of stay was 8 days, and the median cost of hospitalization was 970.59 US dollars. This study will help understand the epidemiological characteristics and disease burden of hospitalized children with IM in China.

EBV-positive diffuse large B-cell lymphoma, not otherwise specified: 2022 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Epstein Barr virus-positive (EBV+) diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS) is an entity included in the WHO classification of lymphoid neoplasms since 2016. EBV+ DLBCL, NOS, is an aggressive B-cell lymphoma associated with EBV infection, and a poor prognosis with standard chemotherapeutic approaches.

DIAGNOSIS

The diagnosis is made through a careful pathological evaluation. Detection of EBV-encoded RNA (EBER) is considered standard for diagnosis; however, a clear cutoff for percentage of positive cells has not been defined. The differential diagnosis includes plasmablastic lymphoma (PBL), DLBCL associated with chronic inflammation, primary effusion lymphoma (PEL), among others.

RISK-STRATIFICATION

The International Prognostic Index (IPI) and the Oyama score can be used for risk-stratification. The Oyama score includes age >70 years and presence of B symptoms. The expression of CD30 and PD-1/PD-L1 are emerging as potential adverse but targetable biomarkers.

MANAGEMENT

Patients with EBV+ DLBCL, NOS, should be staged and managed following similar guidelines than patients with EBV-negative DLBCL. EBV+ DLBCL, NOS, however, might have a worse prognosis than EBV-negative DLBCL in the era of chemoimmunotherapy. Therefore, the inclusion of patients in clinical trials when available is recommended. There is an opportunity to study and develop targeted therapy in the management of patients with EBV+ DLBCL, NOS.

Chronic active Epstein-Barr virus enteritis: A literature review

Chronic active Epstein-Barr virus (CAEBV) enteritis is a rare disease that has not been well described. Owing to the similarities between CAEBV enteritis and inflammatory bowel diseases such as ulcerative colitis and Crohn's disease, it is easy to be misdiagnosed and mistreated in clinical practice, resulted in complications and even death in severe cases. Through a literature review, this study aimed to summarize the clinical characteristics, pathological features, examinations, and treatment strategies of CAEBV enteritis and its similarities and differences with inflammatory bowel diseases.

Case Report: Chronic Active Epstein–Barr Virus Infection With Subcutaneous Nodules and Systemic Damage

Chronic active Epstein–Barr virus (CAEBV) infection is a rare and progressive systemic lymphoproliferative disorder often beginning as an infectious mononucleosis (IM)-like illness. It manifests with fever, splenomegaly, hepatitis, lymphadenopathy, and occasionally cytopenias, pneumonitis, and vasculitis. We report a 23-year-old woman with fever and subcutaneous nodules first appearing on the limbs and then spreading to the body. Peripheral blood EBV antibodies were elevated and EBV-DNA loads significantly increased. A skin and lymph node biopsy identified T cell-based lymphocyte infiltration and EBV-encoded RNA positivity (EBER+). CAEBV was finally diagnosed. During the illness, her disease progressed to hemophagocytic syndrome (HPS). The patient then successfully received an allogeneic hematopoietic stem cell transplantation (HSCT) at 6 months. Current follow-up at 2 years indicated a stable condition and six negative EBV-DNA tests, and we reviewed the clinical manifestations, mechanism, diagnosis and differential diagnosis, treatment, and prognosis of CAEBV. Finally, subcutaneous nodules may occur when CAEBV invades the skin; therefore, clinicians must identify the cause of these nodules early. HSCT is effective but its timing must be appropriate.

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

BACKGROUND

Gastric cancer (GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), and genetic components.

AIM

To investigate microbiomes and host genome instability by cost-effective, low-coverage whole-genome sequencing, as biomarkers for GC subtyping.

METHODS

Samples from 40 GC patients were collected from Taizhou Hospital, Zhejiang Province, affiliated with Wenzhou Medical University. DNA from the samples was subjected to low-coverage whole-genome sequencing with a median genome coverage of 1.86 × (range: 1.03 × to 3.17 ×) by Illumina × 10, followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.

RESULTS

Of the 40 GC samples, 20 (50%) were found to be enriched with microbiomes. EBV DNA was detected in 5 GC patients (12.5%). H. pylori DNA was found in 15 (37.5%) patients. The other 20 (50%) patients were found to have relatively higher genomic instability. Copy number amplifications of the oncogenes, ERBB2 and KRAS, were found in 9 (22.5%) and 7 (17.5%) of the GC samples, respectively. EBV enrichment was found to be associated with tumors in the gastric cardia and fundus. H. pylori enrichment was found to be associated with tumors in the pylorus and antrum. Tumors with elevated genomic instability showed no localization and could be observed in any location. Additionally, H. pylori-enriched GC was found to be associated with the Borrmann type II/III and gastritis history. EBV-enriched GC was not associated with gastritis. No statistically significant correlation was observed between genomic instability and gastritis. Furthermore, these three different molecular subtypes showed distinct survival outcomes (P = 0.019). EBV-positive tumors had the best prognosis, whereas patients with high genomic instability (CIN+) showed the worst survival. Patients with H. pylori infection showed intermediate prognosis compared with the other two subtypes.

CONCLUSION

Thus, using low-coverage whole-genome sequencing, GC can be classified into three categories based on disease etiology; this classification may prove useful for GC diagnosis and precision medicine.

Muscle Involvement Caused by Chronic Active Epstein-Barr Virus Infection on 18F-FDG PET/CT in a Pediatric Patient

ABSTRACT

A 7-year-old girl with chronic active EBV (CAEBV) infection-associated hemophagocytic lymphohistiocytosis presented with fever. 18F-FDG PET/CT revealed heterogeneous FDG uptake in multiple muscle groups without significant abnormal activity elsewhere. On repeat FDG PET/CT scan 1 year later after therapy, the abnormal activity in muscles disappeared. Skeletal muscle involvement by CAEBV infection should be included as differential diagnosis for increased muscle activity on FDG PET/CT study.

Genetic errors of immunity distinguish pediatric nonmalignant lymphoproliferative disorders

BACKGROUND

Pediatric nonmalignant lymphoproliferative disorders (PLPDs) are clinically and genetically heterogeneous. Long-standing immune dysregulation and lymphoproliferation in children may be life-threatening, and a paucity of data exists to guide evaluation and treatment of children with PLPD.

OBJECTIVE

The primary objective of this study was to ascertain the spectrum of genomic immunologic defects in PLPD. Secondary objectives included characterization of clinical outcomes and associations between genetic diagnoses and those outcomes.

METHODS

PLPD was defined by persistent lymphadenopathy, lymph organ involvement, or lymphocytic infiltration for more than 3 months, with or without chronic or significant Epstein-Barr virus (EBV) infection. Fifty-one subjects from 47 different families with PLPD were analyzed using whole exome sequencing.

RESULTS

Whole exome sequencing identified likely genetic errors of immunity in 51% to 62% of families (53% to 65% of affected children). Presence of a genetic etiology was associated with younger age and hemophagocytic lymphohistiocytosis. Ten-year survival for the cohort was 72.4%, and patients with viable genetic diagnoses had a higher survival rate (82%) compared to children without a genetic explanation (48%, P = .03). Survival outcomes for individuals with EBV-associated disease and no genetic explanation were particularly worse than outcomes for subjects with EBV-associated disease and a genetic explanation (17% vs 90%; P = .002). Ascertainment of a molecular diagnosis provided targetable treatment options for up to 18 individuals and led to active management changes for 12 patients.

CONCLUSIONS

PLPD defines children at high risk for mortality, and whole exome sequencing informs clinical risks and therapeutic opportunities for this diagnosis.

Epstein-Barr virus miR-BHRF1-3 targets the BZLF1 3'UTR and regulates the lytic cycle

Suppression of lytic viral gene expression is a key aspect of the Epstein-Barr virus (EBV) life cycle to facilitate the establishment of latent infection. Molecular mechanisms regulating transitions between EBV lytic replication and latency are not fully understood. Here, we investigated the impact of viral microRNAs on the EBV lytic cycle. Through functional assays, we found that miR-BHRF1-3 attenuates EBV lytic gene expression following reactivation. To understand the miRNA targets contributing to this activity, we performed Ago PAR-CLIP analysis on EBV-positive, reactivated Burkitt's lymphoma cells and identified multiple miR-BHRF1-3 interactions with viral transcripts. Using luciferase reporter assays, we confirmed a miRNA interaction site within the 3'UTR of BZLF1 which encodes the essential immediate early (IE) transactivator Zta. Comparison of >850 published EBV genomes identified sequence polymorphisms within the miR-BHRF1-3 locus that deleteriously affect miRNA expression and function. Molecular interactions between the homologous viral miRNA, miR-rL1-17, and IE transcripts encoded by rhesus lymphocryptovirus were further identified. Our data demonstrate that regulation of IE gene expression by a BHRF1 miRNA is conserved amongst lymphocryptoviruses, and further reveal virally-encoded genetic elements that orchestrate viral antigen expression during the lytic cycle. Importance Epstein-Barr virus infection is predominantly latent in healthy individuals, while periodic cycles of reactivation are thought to facilitate persistent lifelong infection. Lytic infection has been linked to development of certain EBV-associated diseases. Here, we demonstrate that EBV miR-BHRF1-3 can suppress lytic replication by directly inhibiting Zta expression. Moreover, we identify nucleotide variants that impact the function of miR-BHRF1-3, which may contribute to specific EBV pathologies.

Haploidentical hematopoietic stem cell transplantation for pediatric patients with chronic active Epstein-Barr virus infection: a retrospective analysis of a single center

BACKGROUND

This study aimed to evaluate the feasibility and clinical effect of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for the treatment of pediatric patients with chronic active Epstein-Barr virus infection (CAEBV).

METHODS

Children with CAEBV who did not have matched donors and underwent haplo-HSCT in Beijing Children's Hospital, Capital Medical University, from October 2016 to June 2020 were analyzed retrospectively. Data relating to the clinical manifestations, engraftment, and prognosis of the children were extracted from medical records.

RESULTS

Twenty-five patients, including 16 males and 9 females, with an onset age of 5.0 ± 2.6 years and a transplantation age of 6.9 ± 2.9 years, were enrolled in this study. The mean time from diagnosis to transplantation was 3.8 (2.0-40.2) months. The mean observation time was 19.0 ± 12.0 months. Three patients received the reduced intensity conditioning regimen, and the remaining patients all received the modified myeloablative conditioning regimen. By the end of the follow-up, 23 patients were characterized by disease-free survival (DFS), 22 were characterized by event-free survival (EFS), and two died. One of the patients died of thrombotic microangiopathy (TMA), and another died of graft versus host disease (GVHD); this patient discontinued the treatment for economic reasons. The 3-year overall survival (OS) rate was estimated to be 92.0% ± 5.4%, and the 3-year EFS rate was estimated to be 87.4% ± 6.8%. All active patients survived after HSCT event-free. Acute GVHD degrees 1-3 were observed in ten patients (40.0%), and degree IV was observed in six (24.0%), who were all cured except for one patient. Chronic GVHD was observed in nine (36.0%), and most of these cases were mild. The incidence of TMA and veno-occlusive disease (VOD) was 28.0% and 4.0%.

CONCLUSIONS

Haploidentical hematopoietic stem cell transplantation is safe and effective in the treatment of pediatric CAEBV and can be used as an alternative therapy without matched donors or emergency transplantation. Patients with active disease before HSCT also benefited from haplo-HSCT. Haplo-HSCT requires careful monitoring for complications, such as GVHD and TMA. Early detection of TMA and timely treatment can reduce mortality and can improve the survival rate.