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

Epstein-Barr virus-mediated immune evasion in tumor promotion

Epstein-Barr virus (EBV) was the first DNA virus identified to be tightly associated with multiple human tumors. It promotes malignant progression of tumors - including related lymphomas, nasopharyngeal carcinoma, and gastric adenocarcinoma - in part by evading surveillance and attack by the host immune system. In this article we review the main molecular mechanisms by which EBV-encoded proteins and RNAs interact with key molecules of the host immune system to inhibit Toll-like receptor (TLR)-nuclear factor κB (NF-κB), retinoic acid-inducible gene I (RIG-I), and interferon (IFN) signaling pathways, affect antigen presentation, prevent the cytotoxic effects of CD8+ effector cells, regulate the tumor microenvironment (TME) and cell metastasis and invasion, and inhibit cell apoptosis. These interactions not only contribute to the persistence of the virus but also provide potential targets for developing new immunotherapy strategies.

Clinicopathologic Insights and Molecular Oncogenesis: Understanding Epstein-Barr Virus-Induced B-cell Lymphoproliferations

Epstein-Barr virus (EBV) is a highly prevalent virus among adults worldwide. In an immunocompetent individual, EBV infection generally results in lifelong latency of the virus and no sequelae. However, in the setting of immune dysfunction, EBV can induce the development of autoimmune disorders, hyperplastic proliferations, and cancers, including lymphoma. Here, we explore the pathogenic and oncogenic role of EBV in Burkitt lymphoma, diffuse large B-cell lymphoma, Hodgkin lymphoma, plasmablastic lymphoma, lymphomatoid granulomatosis, and post-transplant lymphoproliferative disorders and lymphoproliferative disorders associated with immune deficiency and dysregulation. In addition to describing general mechanisms of EBV-associated oncogenesis, we also discuss EBV-associated oncogenesis in the context of each disorder, as well as their microscopic, phenotypic, and clinical presentations.

Histiocytoses and reactive proliferations of histiocytes: current state of the art and evolving concepts-a report from the joint CSHP-EA4HP-SH workshop 2024, Hefei, China

Reactive and clonal proliferations of histiocytes (macrophages/dendritic cells) represent a broad spectrum of disorders, which can affect virtually any organ of the body. The clinical spectrum ranges from benign, localized and self-limiting manifestations to severe multi-system disease. Hemophagocytic lymphohistiocytosis (HLH) is a frequently life-threatening, systemic hyperinflammatory process triggered by massive cytokine release by activated, reactive macrophages. Familial and secondary forms of HLH are discerned. Histiocytoses are clonal inflammatory myeloid disorders characterized by proliferations of mature histiocytes/macrophages and dendritic cells with recurrent kinase-activating mutations which result in constitutive activation of the ERK signaling pathway. Although traditionally subclassified according to the phenotype of the lesional cells, the clonal cells can show significant plasticity, and the occurrence of mixed histiocytoses is increasingly recognized. This is in part due to their derivation from a myeloid progenitor cell and explains the frequent association with clonal hematopoiesis or overt myeloid neoplasms in adults. At the joint Workshop of the Chinese Society of Hematopathology, the European Association for Haematopathology and the Society for Hematopathology on histiocytic/dendritic cell proliferations, neoplasms, and their mimics in Hefei, China, April 2024, in sessions 1 and 2 a total of 8 cases of HLH, 9 cases of reactive histiocytic proliferations and 40 cases of histiocytoses were submitted and reviewed by the panel. The latter included cases of LCH, indeterminate cell histiocytosis, Erdheim Chester disease, juvenile xanthogranuloma, Rosai Dorfman disease, multicentric reticulohistiocytosis, ALK-positive histiocytosis, and mixed histiocytoses. The present report summarizes important findings and open questions arising from discussing the workshop cases.

An Update on EBV-related Cutaneous Lymphoproliferative Disorders: a Systematic Review

Epstein Barr virus (EBV) positive B lymphoproliferative disorders (LPD) with cutaneous involvement include a series of rare entities that go from indolent processes to aggressive lymphomas. B-cell EBV+ LPD mainly affect immunocompromised patients while T-cell EBV+ LPD are more prevalent in specific geographic regions such as Asia, Central America, and South America. Since the latest WHO-EORTC classification of cutaneous lymphomas in 2018, significant changes have been included in the new classifications of hematological malignancies. This systematic review summarizes the main clinical, histological, immunophenotypic and molecular characteristics of B- and T-cell EBV+ LPD that may compromise the skin at diagnosis. B-cell EBV+ LPD include primary cutaneous lymphomas such as EBV-Mucocutaneous Ulcer, as well as systemic lymphomas affecting the skin at diagnosis that may present such as lymphomatoid granulomatosis (LG), EBV diffuse large B cell lymphoma, NOS, plasmablastic lymphoma (PBL), Extracavitary primary effusion lymphoma (EC-PEL) EBV+, EBV-positive polymorphic B cell LPD, and post-transplant lymphoproliferative disorders (PTLD). Regarding T-cell EBV+ LPD, most of these entities are categorized within T/NK-cell lymphoproliferative processes and lymphomas of childhood, including extranodal T/NK lymphoma, and even more exceptional forms such as EBV-positive T-cell centrofollicular lymphoma and intravascular T/NK-cell lymphoma. Diagnosis is based on integrating the clinical, histological, immunohistochemical, and genetic criteria discussed throughout this article. Differential diagnosis is a challenge for dermatologists and pathologists, so having scientific evidence available in this field is of paramount importance because overtreatment must be carefully avoided.

[Translated article] An Update on EBV-related Cutaneous Lymphoproliferative Disorders: a Systematic Review

Epstein Barr virus (EBV) positive lymphoproliferative disorders (LPD) with cutaneous involvement include a series of rare entities that go from indolent processes to aggressive lymphomas. B-cell EBV+ LPD mainly affect immunocompromised patients while T-cell EBV+ LPD are more prevalent in specific geographic regions such as Asia, Central America, and South America. Since the latest WHO-EORTC classification of cutaneous lymphomas in 2018, significant changes have been included in the new classifications of hematological malignancies. This systematic review summarizes the main clinical, histological, immunophenotypic and molecular characteristics of B- and T-cell EBV+ LPD that may compromise the skin at diagnosis. B-cell EBV+ LPD include primary cutaneous lymphomas such as EBV-Mucocutaneous Ulcer, as well as systemic lymphomas affecting the skin at diagnosis that may present such as lymphomatoid granulomatosis (LG), EBV diffuse large B cell lymphoma, NOS, plasmablastic lymphoma (PBL), extracavitary primary effusion lymphoma (EC-PEL) EBV+, EBV-positive polymorphic B cell LPD, and post-transplant lymphoproliferative disorders (PTLD). Regarding T-cell EBV+ LPD, most of these entities are categorized within T/NK-cell lymphoproliferative processes and lymphomas of childhood, including extranodal T/NK lymphoma, and even more exceptional forms such as EBV-positive T-cell centrofollicular lymphoma and intravascular T/NK-cell lymphoma. Diagnosis is based on integrating the clinical, histological, immunohistochemical, and genetic criteria discussed throughout this article. Differential diagnosis is a challenge for dermatologists and pathologists, so having scientific evidence available in this field is of paramount importance because overtreatment must be carefully avoided.

Malignancy-associated HLH: mechanisms, diagnosis, and treatment of a severe hyperinflammatory syndrome

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome characterized by uncontrolled immune activation. While traditionally associated with genetic mutations affecting cytotoxic function, recent advances have highlighted the prevalence and significance of HLH in adults, particularly in hematologic malignancies. This review focuses on malignancy-associated HLH (M-HLH), a complex and challenging condition with a poor prognosis. The review explores four main subtypes of M-HLH: (1) HLH as the initial presentation of malignancy, (2) Chemotherapy Associated HLH, (3) Cytokine Release Syndrome (CRS) Associated HLH-like Syndrome, and (4) immune effector cell-associated HLH-like syndrome. Diagnosis is complicated by overlap with cancer symptoms and limitations of existing criteria. The Optimized HLH Inflammatory (OHI) index shows promise in early identification of hyperinflammation in new-onset hematologic malignancies. Treatment approaches must balance controlling hyperinflammation with addressing the underlying malignancy. Emerging therapies, including targeted agents like anakinra, ruxolitinib, and emapalumab, offer new management possibilities. This review examines the current understanding of M-HLH pathophysiology, diagnostic approaches, and treatment strategies for each subtype. It underscores the critical need for further research to unravel underlying mechanisms and establish evidence-based treatment protocols. Given the complexity of M-HLH, international collaborative efforts are essential to advance knowledge and improve patient outcomes.

Epstein-Barr virus-associated B-cell lymphoproliferative disorders and lymphomas: Diagnostic overlaps and defining features

This review explores four Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorders (LPD) and lymphomas with significant diagnostic overlap: EBV(+) mucocutaneous ulcer (EBVMCU), EBV(+) polymorphic LPD, EBV(+) classic Hodgkin lymphoma (CHL), and EBV(+) diffuse large B-cell lymphoma (DLBCL). Each entity is compared for both overlapping and defining features of clinical presentation, morphology, immunohistochemical profile and EBV expression pattern and latency. Our aims for this review are to provide useful guidance to the practicing pathologist in the diagnosis of these EBV-associated entities.

The 'Oma's of the Gammas-Cancerogenesis by γ-Herpesviruses

Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), which are the only members of the gamma(γ) herpesviruses, are oncogenic viruses that significantly contribute to the development of various human cancers, such as Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's lymphoma, Kaposi's sarcoma, and primary effusion lymphoma. Oncogenesis triggered by γ-herpesviruses involves complex interactions between viral genetics, host cellular mechanisms, and immune evasion strategies. At the genetic level, crucial viral oncogenes participate in the disruption of cell signaling, leading to uncontrolled proliferation and inhibition of apoptosis. These viral proteins can modulate several cellular pathways, including the NF-κB and JAK/STAT pathways, which play essential roles in cell survival and inflammation. Epigenetic modifications further contribute to EBV- and KSHV-mediated cancerogenesis. Both EBV and KSHV manipulate host cell DNA methylation, histone modification, and chromatin remodeling, the interplay of which contribute to the elevation of oncogene expression and the silencing of the tumor suppressor genes. Immune factors also play a pivotal role in the development of cancer. The γ-herpesviruses have evolved intricate immune evasion strategies, including the manipulation of the major histocompatibility complex (MHC) and the release of cytokines, allowing infected cells to evade immune detection and destruction. In addition, a compromised immune system, such as in HIV/AIDS patients, significantly increases the risk of cancers associated with EBV and KSHV. This review aims to provide a comprehensive overview of the genetic, epigenetic, and immune mechanisms by which γ-herpesviruses drive cancerogenesis, highlighting key molecular pathways and potential therapeutic targets.

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.

CD30 influences germinal center B-cell dynamics and the expansion of IgG1-switched B cells

Initially, identified as a Hodgkin lymphoma marker, CD30 was subsequently detected on a subset of human B cells within and around germinal centers (GCs). While CD30 expression is typically restricted to a few B cells, expansion of CD30-expressing B cells occurs in certain immune disorders and during viral infections. The role of CD30 in B cells remains largely unclear. To address this gap in knowledge, we established a conditional CD30-knockin mouse strain. In these mice, B-cell-specific CD30 expression led to a normal B-cell phenotype in young mice, but most aged mice exhibited significant expansion of B cells, T cells and myeloid cells and increased percentages of GC B cells and IgG1-switched cells. This may be driven by the expansion of CD4+ senescence-associated T cells and T follicular helper cells, which partially express CD30-L (CD153) and may stimulate CD30-expressing B cells. Inducing CD30 expression in antigen-activated B cells accelerates the GC reaction and augments plasma cell differentiation, possibly through the posttranscriptional upregulation of CXCR4. Furthermore, CD30 expression in GC B cells promoted the expansion of IgG1-switched cells, which displayed either a GC or memory-like B-cell phenotype, with abnormally high IgG1 levels compared with those in controls. These findings shed light on the role of CD30 signaling in GC B cells and suggest that elevated CD30+ B-cell numbers lead to pathological lymphocyte activation and proliferation.

From the midfacial destructive drama to the unfolding EBV story: a short history of EBV-positive NK-cell and T-cell lymphoproliferative diseases

Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus that has been related to oncogenesis of lymphoid and epithelial malignancies. Although the mechanism of EBV infection of NK and T cells remains enigmatic, it plays a pathogenic role in various EBV+ NK-cell and T-cell lymphoproliferative diseases (LPDs), through promotion of cell activation pathways, inhibition of cell apoptotic pathways, behaving as oncogenes, interacting with host oncogenes or acting epigenetically. The study of NK-cell LPDs, previously hampered by the lack of immunophenotypical and genotypical criteria of NK cells, has become feasible with the recently accepted criteria. EBV+ NK- and T-cell LPDs are mostly of poor prognosis. This review delivers a short history from primeval to recent EBV+ NK- and T-cell LPDs in non-immunocompromised subjects, coupled with increasing interest, and work on the biological and oncogenic roles of EBV.

The significance of stem cell-like memory T cells in viral and bacterial vaccines: A mini review

Vaccination has become a widely used method to induce immune protection against microbial pathogens, including viral and bacterial microorganisms. Both humoral and cellular immunity serve a critical role in neutralizing and eliminating these pathogens. An effective vaccine should be able to induce a long-lasting immune memory response. Recent investigations on different subsets of T cells have identified a new subset of T cells using multi-parameter flow cytometry, which possess stem cell-like properties and the ability to mount a rapid immune response upon re-exposure to antigens known as stem cell-like memory T cells (TSCM). One of the major challenges with current vaccines is their limited ability to maintain long-term memory in the adaptive immune system. Recent evidence suggests that a specific subgroup of memory T cells has the unique ability to retain their longevity for up to 25 years, as observed in the case of the yellow fever vaccine. Therefore, in this study, we tried to explore and discuss the potential role of this new T cell memory subset in the development of viral and bacterial vaccines.

Epstein-Barr Virus-Positive Mucosal Skin Ulcer Resulting in Oral Lesions During Concomitant Use of Tacrolimus and Prednisolone

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a subtype of Epstein-Barr virus-positive lymphoproliferative disease with a favorable prognosis that can develop either due to medical interventions or as a consequence of aging. Medical-onset cases caused by immunosuppressive drugs may require a reduction or discontinuation of the causative drugs. However, specific methods for drug adjustment in cases where multiple immunosuppressive drugs are used have not yet been established. Herein, we present the case of a 63-year-old man with interstitial pneumonia who developed an EBVMCU on the right side of his tongue. He was on multidrug therapy with tacrolimus and prednisolone and was treated conservatively by discontinuation of the tacrolimus and switching to prednisolone monotherapy. The lesion resolved within two months following the adjustment. This case report provides evidence that conversion to monotherapy, rather than multiple immunosuppressive drugs, is a potentially effective treatment option for EBVMCU.

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.

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.

An Unusual Case of Recurrent Gingival Epstein-Barr Virus-Positive B-Cell Lymphoproliferation

Epstein-Barr virus (EBV)-positive mucocutaneous ulceration commonly presents as a B-cell lymphoproliferative process with manifold aspects. There is scarce data on its oral manifestation in the scientific literature. We report the case of a 57-year-old male immunocompromised renal transplant patient who developed recurrent chronic and symptomatic mucosal ulceration facing the mandibular incisor teeth. Pathological examination with microscopic and immunohistochemistry studies revealed a B plasma cell infiltration as well as positive staining for EBV, leading to a diagnosis of EBV-positive mucocutaneous ulceration with B-cell lymphoproliferation after extensive workup. Treatment with rituximab was implemented and led to the healing of the lesion. This lesion develops in geriatric and immunodeficient patients and may require oncological therapies. While it is generally associated with an excellent prognosis, it may be indicative of underlying immunosuppression, and hence oral cavity specialists must be aware of this particular entity.

Differences in the Tumor Microenvironment of EBV-Associated Gastric Cancers Revealed Using Single-Cell Transcriptome Analysis

Epstein-Barr virus (EBV) is a gamma-herpesvirus associated with nearly 10% of gastric cancers (GCs). These EBV-associated GCs (EBVaGCs) are molecularly, histopathologically, and clinically distinct from EBV-negative GCs (EBVnGCs). While viral genes in EBVaGCs contribute to the carcinogenesis process, viral proteins also represent foreign antigens that could trigger enhanced immune responses compared to EBVnGCs. Despite prior investigations of the EBVaGC tumor microenvironment (TME), the cellular composition has not been thoroughly explored. In this study, cellular subpopulations overrepresented in EBVaGCs were identified and molecularly characterized. Genes consistently expressed across both bulk tumor and single-cell RNA sequencing data were highlighted, with the expression across the identified cellular subpopulations analyzed. As expected, based on existing histopathological analysis, EBVaGC is characterized by abundant lymphocytic infiltration of the stroma. Our molecular analysis identified three unique immune cell subpopulations in EBVaGC: T and B cells expressing high levels of proliferation markers and B cells expressing T cell features. The proliferating T cell cluster also expressed markers of follicular T helper cells. Overall, EBVaGC also exhibited unique features indicative of a higher inflammatory response. These substantial differences within the TME suggest that further detailed exploration of the cellular composition of EBVaGCs is needed, which may identify cellular subpopulations and phenotypes associated with patient outcomes.

Cardiovascular involvement in Epstein-Barr virus infection

Cardiovascular involvement is an uncommon but severe complication of Epstein-Barr virus (EBV) infection caused by direct damage and immune injury. Recently, it has drawn increasing attention due to its dismal prognosis. It can manifest in various ways, including coronary artery dilation (CAD), coronary artery aneurysm (CAA), myocarditis, arrhythmias, and heart failure, among others. If not treated promptly, cardiovascular damage can progress over time and even lead to death, which poses a challenge to clinicians. Early diagnosis and treatment can improve the prognosis and reduce mortality. However, there is a lack of reliable large-scale data and evidence-based guidance for the management of cardiovascular damage. Consequently, in this review, we attempt to synthesize the present knowledge of cardiovascular damage associated with EBV and to provide an overview of the pathogenesis, classification, treatment, and prognosis, which may enhance the recognition of cardiovascular complications related to EBV and may be valuable to their clinical management.

An update on viral-induced cutaneous lymphoproliferative disorders. CME Part I

Viral-induced cutaneous T-cell lymphomas are an uncommon group of lymphoproliferative disorders characterized by a viral infection of T and natural killer (NK) cells. This group of cutaneous T-cell lymphomas is more commonly encountered in Asians and Native Americans from Central and South America compared with Western populations. Viral-associated lymphoproliferative disorders include a spectrum of entities that range from nonneoplastic lesions, such as chronic active Epstein-Barr virus infection and infective dermatitis to malignant diseases, such as extranodal NK/T-cell lymphoma, hydroa vacciniforme-like T-cell lymphoma, and adult T-cell leukemia/lymphoma. This review article will focus on hydroa vacciniforme-like lymphoproliferative disorder, extranodal NK/T-cell lymphoma, adult T-cell leukemia/lymphoma, lymphomatoid granulomatosis, and Epstein-Barr virus-positive mucocutaneous ulcers. We will review the pathogenesis of these conditions and the challenges of making a timely diagnosis in early-stage disease and discuss the common clinicopathologic manifestations, mutational landscape, and approaches to treat these highly aggressive and frequently lethal types of lymphoma.

[Classification of Hodgkin lymphoma and related entities : News and open questions]

Two new classifications were recently released: the 5th edition of the WHO classification of hematolymphoid tumors and the International Consensus Classification (ICC) drafted by the Clinical Advisory Committee. In the preparation of both classifications, the previously existing lymphoma categories were reevaluated according to recently obtained data on clinical, morphological, and molecular findings. In this review we summarize the current placements of classic and nodular lymphocyte predominant Hodgkin lymphoma and their relevant differential diagnoses.

Epstein-Barr Virus and the Pathogenesis of Diffuse Large B-Cell Lymphoma

Epstein-Barr virus (EBV), defined as a group I carcinogen by the World Health Organization (WHO), is present in the tumour cells of patients with different forms of B-cell lymphoma, including Burkitt lymphoma, Hodgkin lymphoma, post-transplant lymphoproliferative disorders, and, most recently, diffuse large B-cell lymphoma (DLBCL). Understanding how EBV contributes to the development of these different types of B-cell lymphoma has not only provided fundamental insights into the underlying mechanisms of viral oncogenesis, but has also highlighted potential new therapeutic opportunities. In this review, we describe the effects of EBV infection in normal B-cells and we address the germinal centre model of infection and how this can lead to lymphoma in some instances. We then explore the recent reclassification of EBV+ DLBCL as an established entity in the WHO fifth edition and ICC 2022 classifications, emphasising the unique nature of this entity. To that end, we also explore the unique genetic background of this entity and briefly discuss the potential role of the tumour microenvironment in lymphomagenesis and disease progression. Despite the recent progress in elucidating the mechanisms of this malignancy, much work remains to be done to improve patient stratification, treatment strategies, and outcomes.

Meta-Analysis of MS-Based Proteomics Studies Indicates Interferon Regulatory Factor 4 and Nucleobindin1 as Potential Prognostic and Drug Resistance Biomarkers in Diffuse Large B Cell Lymphoma

The prognosis of diffuse large B cell lymphoma (DLBCL) is inaccurately predicted using clinical features and immunohistochemistry (IHC) algorithms. Nomination of a panel of molecules as the target for therapy and predicting prognosis in DLBCL is challenging because of the divergences in the results of molecular studies. Mass spectrometry (MS)-based proteomics in the clinic represents an analytical tool with the potential to improve DLBCL diagnosis and prognosis. Previous proteomics studies using MS-based proteomics identified a wide range of proteins. To achieve a consensus, we reviewed MS-based proteomics studies and extracted the most consistently significantly dysregulated proteins. These proteins were then further explored by analyzing data from other omics fields. Among all significantly regulated proteins, interferon regulatory factor 4 (IRF4) was identified as a potential target by proteomics, genomics, and IHC. Moreover, annexinA5 (ANXA5) and nucleobindin1 (NUCB1) were two of the most up-regulated proteins identified in MS studies. Functional enrichment analysis identified the light zone reactions of the germinal center (LZ-GC) together with cytoskeleton locomotion functions as enriched based on consistent, significantly dysregulated proteins. In this study, we suggest IRF4 and NUCB1 proteins as potential biomarkers that deserve further investigation in the field of DLBCL sub-classification and prognosis.

Evolution in the definition and diagnosis of the Hodgkin lymphomas and related entities

Hodgkin lymphoma was the first of the lymphomas to be recognized as a specific disease entity. However, recent studies have highlighted the heterogeneity of the diseases associated with this eponym warranting clarification and refinement of diagnostic terminology. While classic Hodgkin lymphoma (CHL) remains an essentially unchanged diagnostic entity in the 2022 International Consensus Classification of Mature Lymphoid Neoplasms (2022 ICC), nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is now renamed nodular lymphocyte predominant B cell lymphoma (NLPBL) in recognition of the distinct pathologic, biologic, and clinical differences. Fan patterns A, B, and C (sharing the presence of evident follicular structures, and retention of a B cell rich background) will be combined in "typical" or grade 1, while the other "variant" patterns, D, E, and F, are considered grade 2. T-cell/histiocyte-rich large B cell lymphoma (THRBCL) is considered part of the "variant" NLPHL continuum.The entity previously known as "B cell lymphoma, unclassifiable (BCLU), with features intermediate between diffuse large B cell lymphoma (DLBCL) and CHL" has been renamed "mediastinal gray zone lymphoma" (MGZL) in recognition of the importance of the thymic niche in the biology of this tumor. The diagnostic criteria for MGZL have been refined and require both a high tumor cell density and a strongly preserved B cell program.This article will describe updates on CHL, NLPBL, and MGZL in the recently published 2022 ICC and provide some useful differential diagnostic clues in cases with atypical morphology or immunophenotype.

Chronic active Epstein-Barr virus infection involving gastrointestinal tract with hemophagocytic lymphohistiocytosis

Chronic active EBV infection (CAEBV) is a lymphoproliferative disorder of T- or NK-cell type in Asian countries. CAEBV involving the gastrointestinal tract (GI CAEBV) is a rare condition with poor prognosis that may rapidly progress with hemophagocytic lymphohistiocytosis (HLH) and life-threatening complications such as GI bleeding and/or perforation. The approach to CAEBV with GI tract involvement (GI CAEBV) is still an unmet clinical need. In this case series study, we summarized the clinical features, treatment, and prognosis of seven cases of GI CAEBV with HLH, particularly focusing on its prognosis and the possible salvage therapy combining surgery, novel therapeutic agents, and/or autologous(auto-) hematopoietic stem cell transplantation (HSCT) based on successful cases from our center. GI CAEBV is often misdiagnosed as inflammatory bowel diseases and certain infections. The key to its early recognition is the integrative consideration of its systemic manifestation, serum virology, endoscopic, and imaging findings along with pathology. Surgical intervention should not be hesitated when life-threatening GI complications occur. Resection of the involved bowel segment is an effective way of controlling bleeding and reducing tumor burden. In addition to upfront allogeneic HSCT, new therapeutic modalities including PD-1 antibody and auto-HSCT may be effective in certain patients.

Intravascular NK/T-Cell Lymphoma: What We Know about This Diagnostically Challenging, Aggressive Disease

Intravascular lymphoma is a form of lymphoid malignancy characterized by neoplastic cells growing almost exclusively within the lumina of small- to medium-sized blood vessels. Most cases are of B-cell origin with rare cases of natural killer or T-cell lineage. Extranodal sites are affected, mainly the skin and central nervous system, although any organ may be involved. Intravascular NK/T-cell lymphoma deserves special attention because of its clinicopathologic features and the need for adequate immunophenotyping combined with clonality test for a proper diagnosis. Moreover, intravascular NK/T-cell lymphoma is strongly linked to Epstein-Barr virus (EBV), which is considered to play a role in tumorigenesis and to be responsible for the aggressive behavior of the disease. In this paper, we review the current knowledge on this rare lymphoma and, in particular, the most recent advances about its molecular landscape. The main distinguishing features with other EBV-related entities, such as extranodal NK/T-cell lymphoma, EBV-positive primary nodal T/NK-cell lymphoma, and aggressive NK-cell leukemia, are discussed to help pathologists obtain the correct diagnosis and consequently develop an adequate and prompt therapy response.

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.

Herpesvirus infections and post-COVID-19 manifestations: a pilot observational study

The global spread of SARS-CoV-2 points to unrivaled mutational variation of the virus, contributing to a variety of post-COVID sequelae in immunocompromised subjects and high mortality. Numerous studies have reported the reactivation of "sluggish" herpes virus infections in COVID-19, which exaggerate the course of the disease and complicate with lasting post-COVID manifestations CMV, EBV, HHV6). This study aimed to describe clinical and laboratory features of post-COVID manifestations accompanied by the reactivation of herpes virus infections (CMV, EBV, HHV6). 88 patients were recruited for this study, including subjects with reactivation of herpes viruses, 68 (72.3%) (main group) and 20 (27.7%) subjects without detectable DNA of herpesviruses (control group): 46 (52.3%) female and 42 (47.7%) male; median age was 41.4 ± 6.7 years. Patients with post-COVID manifestations presented with reactivation of EBV in 42.6%, HHV6 in 25.0%, and EBV plus HHV6 in 32.4%. Compared with controls, patients with herpes virus infections presented with more frequent slight fever temperature, headache, psycho-neurological disorders, pulmonary abnormalities and myalgia (p < 0.01), activation of liver enzymes, elevated CRP and D-dimer, and suppressed cellular immune response (p ≤ 0.05). Preliminary results indicate a likely involvement of reactivated herpes virus infections, primarily EBV infections in severe COVID-19 and the formation of the post-COVID syndrome. Patients with the post-COVID syndrome and reactivation of EBV and HHV6 infections are at high risk of developing various pathologies, including rheumatologic diseases.

Primary Epstein-Barr Virus-Positive Mucocutaneous Ulcer of Esophagus: A Rare Case Report

Primary EBV-positive mucocutaneous ulcer (EBVMCU) is a rare and indolent disorder occurring in the oropharynx, skin, and gastrointestinal tract, with remission after removal of the immunosuppressive causes. We present a 69-year-old woman with heartburn, regurgitation of gastric acid, enlarged lymph nodes, and parotid glands. The endoscopic examination showed a circumscribed ulcer in the lower esophagus. A biopsy pathology indicated an esophageal EBV-associated lymphoproliferative disorder and a parotid gland/lymph node indolent B-cell lymphoma. Interestingly, the patient did not undergo any treatment, but the endoscopic ulcer improved significantly after more than 2 months. The last pathology showed EBV negativity, and EBVMCU was considered in combination with clinical and endoscopic manifestations. We followed up with the patient at 6 months, and the symptoms of acid reflux and heartburn had disappeared. Our case demonstrates that EBVMCU may occur in the esophagus with spontaneous regression.

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.

[EBV-associated lymphoproliferative disorders]

Epstein-Barr-virus-associated lymphoproliferations (EBV-LPD) constitute a wide spectrum from benign, self-limiting lymphoproliferations to malignant lymphoma. Because of the clinical and morphological heterogeneity of EBV-LPD and the high prevalence of EBV infections, knowledge of the diagnostic criteria is of great importance for the practice of diagnostic pathology. In this review, clinical and pathological characteristics of the non-malignant EBV-related LPD in patients with and without immunosuppression are presented and their current classification is discussed.EBV-LPD can be of B‑cell or T/NK-cell origin. Identification of EBV latency type and information about possible (iatrogenic) immunodeficiency of the patient are critical for diagnostic evaluation and separation from malignant lymphoma. The clinical context and the detection of EBV in T‑ and NK-cells are both essential for the diagnosis of EBV+ T/NK-cell LPD, which are rare in European countries.

A Case of severe mosquito bite allergy complicated by fatal hemophagocytic lymphohistiocytosis

Severe mosquito bite allergy (SMBA) is characterized by necrotic skin lesions and systemic symptoms. Chronic active Epstein-Barr virus (EBV) infection, when superimposed with SMBA, is a key driver for catastrophic clinical consequences, such as uncontrolled lymphoproliferation. This interplay is of clinical significance due to its association with hemophagocytic lymphohistiocytosis (HLH) and/or EBV-driven malignancies. Here, we report a case of SMBA that developed in a 14-year-old Hispanic boy that led to fatal secondary HLH.

Co-Occurrence of EBV-Positive Mucocutaneous Ulcer (EBV-MCU) and CLL/SLL in the Head and Neck Region

EBV-positive mucocutaneous ulcer (EBV-MCU) was classified as a rare new entity of the lymphoproliferative B-cell diseases by the WHO in 2017 and must be distinguished from head and neck squamous cell carcinoma by early biopsy. The aim of the study is to raise awareness of the disease and to give a review of the current literature and a recommendation for EBV-MCU management. All EBV-MCU cases of the head and neck region published so far were included. We also report a case of a pharyngeal EBV-MCU in an 89-year-old patient who was immunosuppressed by chronic lymphatic leukaemia/small lymphocytic lymphoma (CLL/SLL). In contrast to all previously described cases, histopathology showed a co-infiltration of EBV-MCU and CLL/SLL. A total of 181 cases were identified on PubMed and summarised. EBV-MCU was predominantly caused by immunosuppressive drug therapy. Complete remission could be achieved in 68% of cases and was mainly attributed to a reduction of the immunosuppressive therapy alone (72%). However, some severe cases require more aggressive treatment. Regarding the various histopathologic similarities to other lymphoproliferative disorders, the diagnosis of EBV-MCU can be misleading, with a great impact on patient care and treatment. This diagnosis must be made with caution and requires a combination of clinical, morphological and immunophenotypic features.

Epstein-Barr Virus-Positive Lymphoma-Associated Hemophagocytic Syndrome: A Retrospective, Single-Center Study of 51 Patients

Purpose

To investigate clinical characteristics, management, and prognosis of Epstein-Barr virus (EBV)-positive lymphoma-associated hemophagocytic syndrome (LAHS) patients in real-world practice.

Methods

This was a retrospective, single-center cohort study. EBV-positive LAHS patients diagnosed from January 2010 to December 2021 in our center were enrolled. Clinical characteristics, treatment, overall response rate (ORR), and overall survival (OS) were investigated. Univariate and multivariate analysis of potential factors were conducted.

Results

Of the 51 patients, 44 were T/NK cell lymphoma; five were B cell lymphoma; two were Hodgkin lymphoma. EBV-positive T/NK cell LAHS patients were significantly younger and showed lower fibrinogen levels and C-reactive protein levels than EBV-positive B cell LAHS patients (P=0.033, P=0.000, and P=0.004, respectively). Combined treatment of anti-hemophagocytic lymphohistiocytosis (HLH) and anti-lymphoma treatment was conducted in 24 patients; anti-HLH treatment was conducted in 18 patients; anti-lymphoma treatment was conducted in three patients; glucocorticoid treatment was conducted in one patient. ORR was 47.8%, and the median OS was 61 (95% confidence interval 47.9-74.1) days for overall patients. Patients who received anti-HLH treatment and turned to anti-lymphoma treatment early displayed higher ORR and OS than those of anti-HLH patients (P=0.103, and P=0.003, respectively). Elevated alanine aminotransferase level was the independent risk factor of EBV-positive LAHS prognosis.

Conclusions

Prognosis of EBV-positive LAHS patients was poor. Anti-lymphoma treatment should be initiated as soon as HLH was rapidly controlled.

EBV associated T- and NK-cell lymphoproliferative diseases: A comprehensive overview of clinical manifestations and novel therapeutic insights

EBV is a ubiquitous virus that infects nearly all people around the world. Most infected people are asymptomatic and do not show serious sequelae, while others may develop Epstein-Barr virus (EBV)-positive T and NK-cell lymphoproliferations characterised by EBV-infected T or NK cells. These disorders are more common in Asian and Latin American people, suggesting genetic predisposition as a contributing factor. The revised WHO classification classifies the lymphoproliferative diseases as: extranodal NK/T-cell lymphoma nasal type (ENKTL), aggressive NK-cell leukemia (ANKL), primary EBV-positive nodal T or NK cell lymphoma (NNKTL), systemic EBV-positive T-cell lymphoproliferative disease of childhood (STCLC), systemic chronic active EBV infection (sys CAEBV), hydroa-vacciniforme (HV) and severe mosquito bite allergy (SMBA). Recent advances in the molecular pathogenesis of these diseases have led to the development of new therapeutic strategies. Due to the infrequency of the diseases and broad clinicopathological overlap, the diagnosis and classification are challenging for both clinicians and pathologists. In this article, we aim to review the recent pathological findings which can be helpful for designing new drugs, clinical presentations and differential diagnoses, and suggested therapeutic interventions to provide a better understanding of these rare disorders.

Fibrin-Associated EBV-Positive Large B-Cell Lymphoma Incidentally Found Within a Multinodular Goiter

Fibrin-associated diffuse large B-cell lymphoma (fibrin-associated DLBCL) is a very rare subtype of Epstein-Barr virus (EBV)-associated DLBCL that usually develops within fibrin-rich lesions such as cardiac myxoma, chronic hematoma, thrombus, pseudocysts or cysts, prosthetic devices or breast implants. The pathogenesis as well as the clinicopathologic features of this usually indolent lymphoproliferative disorder, which are based on the analysis of a relatively limited number of cases, are still poorly known. Herein, we report a case of fibrin-associated DLBCL that was incidentally found within a multinodular goiter, a location not yet reported to our knowledge. Our findings not only illustrate further the specific nature of this peculiar lymphoproliferative disorder but also allow some interesting comments on its pathogenesis.

Estimating the global burden of Epstein-Barr virus-related cancers

BACKGROUND

More than 90% of the adult population globally is chronically infected by the Epstein-Barr virus (EBV). It is well established that EBV is associated with a number of malignancies, and advances in knowledge of EBV-related malignancies are being made every year. Several studies have analysed the global epidemiology and geographic distribution of EBV-related cancers. However, most have only described a single cancer type or subtype in isolation or limited their study to the three or four most common EBV-related cancers. This review will present an overview on the spectrum of cancers linked to EBV based on observations of associations and proportions in the published literature while also using these observations to estimate the incidence and mortality burden of some of these cancers.

METHOD

We have reviewed the literature on defining features, distribution and outcomes across six cancers with a relatively large EBV-related case burden: Nasopharyngeal carcinoma (NPC), Gastric carcinoma (GC), Hodgkin lymphoma (HL), Burkitt lymphoma (BL), Diffuse large B-cell lymphoma (DLBCL) and Extranodal NK/T-cell lymphoma, Nasal type (ENKTL-NT). We retrieved published region-specific EBV-related case proportions for NPC, GC, HL and BL and performed meta-analyses on pooled region-specific studies of EBV-related case proportions for DLBCL and ENKTL-NT. We match these pooled proportions with their respective regional incidence and mortality numbers retrieved from a publicly available cancer database. Additionally, we also reviewed the literature on several other less common EBV-related cancers to summarize their key characteristics herein.

CONCLUSION

We estimated that EBV-related cases from these six cancers accounted for 239,700-357,900 new cases and 137,900-208,700 deaths in 2020. This review highlights the significant global impact of EBV-related cancers and extends the spectrum of disease that could benefit from an EBV-specific therapeutic.

Clinicopathologic Analysis of Primary Adrenal Diffuse Large B-Cell Lymphoma: A Reappraisal of 23 Japanese Patients Based on EBV Association and PD-L1 Expression in Tumor Cells

Primary adrenal diffuse large B-cell lymphoma (PA-DLBCL) is rare. We investigate 23 Japanese patients with PA-DLBCL to understand the clinicopathologic features and biological behavior of this disease. The 17 males and 6 females had a median age of 74 years (range: 40 to 86 y). Tumor cells harbored Epstein-Barr virus-encoded small RNA (EBER) in 9 (39%) samples, including samples from the 2 patients with methotrexate-associated B-cell lymphoproliferative disorder. Programmed cell death ligand 1 (PD-L1) expression was detected in tumor cells of 6 (26%) samples, including 1 EBER+ and 5 EBER- samples. Four (17%) patients exhibited an intravascular proliferating pattern, and all 4 patient samples showed positive staining for PD-L1 in tumor cells. Among those patients, 3 showed intravascular proliferating pattern accompanied by a diffuse extravascular proliferation of tumor cells, and 1 patient was diagnosed with intravascular large B-cell lymphoma. We divided the 23 patients into 3 groups: EBER+ (n=9, 39%), EBER-PD-L1+ (n=5, 22%), and EBER-PD-L1- (n=9, 39%). A comparison of the outcomes among the 3 groups showed significant differences in overall survival (P=0.034). The EBER+ group had the worst prognosis, and the EBER-PD-L1- group had the best prognosis. We also compared the outcomes among the 3 groups that received rituximab-containing chemotherapies. Both the overall survival and progression-free survival were significantly different among these groups (P<0.001 and P=0.002, respectively). In conclusion, we evaluated 3 types of PA-DLBCL and found that each had unique clinical, pathologic, and prognostic features. Our results suggested that immune senescence, iatrogenic immunodeficiency, and immune evasion contribute to the development of PA-DLBCL.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 3)

EBV is the first known oncogenic virus involved in the development of several tumors. The majority of the global population are infected with the virus early in life and the virus persists throughout life, in a latent stage, and usually within B lymphocytes. Despite the worldwide diffusion of EBV infection, EBV-associated diseases develop in only in a small subset of individuals often when conditions of immunosuppression disrupt the balance between the infection and host immune system. EBV-driven lymphoid proliferations are either of B-cell or T/NK-cell origin, and range from disorders with an indolent behavior to aggressive lymphomas. In this review, which is divided in three parts, we provide an update of EBV-associated lymphoid disorders developing in the gastrointestinal tract, often representing a challenging diagnostic and therapeutic issue. Our aim is to provide a practical diagnostic approach to clinicians and pathologists who face this complex spectrum of disorders in their daily practice. In this part of the review, the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders are discussed.

SARS-CoV-2 and EBV; the cost of a second mitochondrial "whammy"?

We, and others, have suggested that as the SARS-CoV-2 virus may modulate mitochondrial function, good mitochondrial reserve and health could be key in determining disease severity when exposed to this virus, as the immune system itself is dependent on this organelle's function. With the recent publication of a paper showing that long COVID could be associated with the reactivation of the Epstein Barr Virus, which is well known to manipulate mitochondria, we suggest that this could represent a second mitochondrial "whammy" that might support the mitochondrial hypothesis underlying COVID-19 severity and potentially, the occurrence of longer-term symptoms. As mitochondrial function declines with age, this could be an important factor in why older populations are more susceptible. Key factors which ensure optimal mitochondrial health are generally those that ensure healthy ageing, such as a good lifestyle with plenty of physical activity. The ability of viruses to manipulate mitochondrial function is well described, and it is now also thought that for evolutionary reasons, they also manipulate the ageing process. Given that slowing the ageing process could well be linked to better economic outcomes, the link between mitochondrial health, economics, COVID-19 and other viruses, as well as lifestyle, needs to be considered.

Disparity analysis and prognostic value of pretreatment whole blood Epstein-Barr virus DNA load and Epstein-Barr encoding region status in lymphomas: A retrospective multicenter study in Huaihai Lymphoma Working Group

Elevated Epstein-Barr virus (EBV) DNA load is common in lymphomas. However, it remains unclear whether the disparity in viral load and its prognostic value in lymphomas are correlated with Epstein-Barr encoding region (EBER) status. In this retrospective multicenter study, we collected the data of pretreatment whole blood EBV DNA (pre-EBV DNA) and EBER status and evaluated their disparity and prognostic values in lymphomas. A total of 454 lymphoma patients from December 2014 to August 2020 were retrospectively retrieved. Mann-Whitney U test, Kruskal-Wallis test and Bonferroni's adjustment were used to explore the disparity of EBV DNA and EBER status in lymphomas. Time-dependent receiver operating characteristic analysis and MaxStat analysis were used to determine optimal cutoff points of pre-EBV DNA load. Univariable and multivariable Cox proportional hazards models were established for the estimation of prognostic factors. The positive rate of EBV DNA in natural killer T-cell lymphoma (NKTL) patients was higher than that in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and Hodgkin lymphoma (HL) patients, and the median positive pre-EBV copy number of NKTL was also higher than that of FL and DLBCL. EBV DNA could clearly distinguish the prognosis of DLBCL, NKTL, HL and peripheral T-cell lymphoma, and the integration of EBER status and EBV DNA could differentiate the prognosis of HL patients. Multivariable results revealed that pre-EBV DNA load had an effect on the prognosis of NKTL, FL and DLBCL. The status of pre-EBV DNA and EBER were disparate. Whole blood pre-EBV DNA predicted the prognosis of lymphomas, and the combination of EBV and EBER status could differentiate the prognosis of HL.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 1)

EBV is the most common persistent virus in humans. The interaction of EBV with B lymphocytes, which are considered the virus reservoir, is at the base of the life-long latent infection. Under circumstances of immunosuppression, the balance between virus and host immune system is altered and hence, EBV-associated lymphoid proliferations may originate. These disorders encompass several entities, ranging from self-limited diseases with indolent behavior to aggressive lymphomas. The virus may infect not only B-cells, but even T- and NK-cells. The occurrence of different types of lymphoid disorders depends on both the type of infected cells and the state of host immunity. EBV-driven lymphoproliferative lesions can rarely occur in the gastrointestinal tract and may be missed even by expert pathologists due to both the uncommon site of presentation and the frequent overlapping morphology and immunophenotypic features shared by different entities. The aim of this review is to provide a comprehensive overview of the current knowledge of EBV-associated lymphoproliferative disorders, arising within the gastrointestinal tract. The review is divided in three parts. In this part, the available data on EBV biology, EBV-positive mucocutaneous ulcer, EBV-positive diffuse large B-cell lymphoma, not otherwise specified and classic Hodgkin lymphoma are discussed.

Diagnostic utility of programmed cell death ligand 1 (clone SP142) immunohistochemistry for malignant lymphoma and lymphoproliferative disorders: A brief review

The programmed cell death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in tumor cell escape from immune control and has been most extensively investigated for therapeutic purposes. However, PD-L1 immunohistochemistry is still not used widely for diagnosis. We review the diagnostic utility of PD-L1 (by clone SP142) immunohistochemistry in large-cell lymphomas, mainly consisting of classic Hodgkin lymphoma (CHL) and diffuse large B-cell lymphoma (DLBCL). Neoplastic PD-L1 (nPD-L1) expression on Hodgkin and Reed-Sternberg cells is well-established among prototypic CHL. Of note, EBV+ CHL often poses a challenge for differential diagnosis from peripheral T-cell lymphoma with EBV+ non-malignant large B-cells; their distinction is based on the lack of PD-L1 expression on large B-cells in the latter. The nPD-L1 expression further provides a good diagnostic consensus for CHL with primary extranodal disease conceivably characterized by a combined pathogenesis of immune escape of tumor cells and immunodeficiency. Compared with CHL, the nPD-L1 expression rate is much lower in DLBCL, highlighting some specific subgroups of intravascular large B-cell lymphoma, primary mediastinal large B-cell lymphoma, and EBV+ DLBCL. They consist of nPD-L1-positive and -negative subgroups, but their clinicopathological significance remains to be elucidated. Microenvironmental PD-L1 positivity on immune cells may be associated with a favorable prognosis in extranodal DLBCL. PD-L1 (by SP142) immunohistochemistry has helped us to understand the immune biology of lymphoid neoplasms possibly related by immune escape and/or immunodeficiency. However, knowledge of these issues remains limited and should be clarified for diagnostic consensus in the future.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 2)

Epstein-Barr virus (EBV) is a common pathogen infecting people primarily early in life. The virus has the ability to persist throughout a person's life, usually in B lymphocytes. Conditions of immunodeficiency as well as the introduction of immunosuppressive therapies and the advent of transplant technologies has brought immunodeficiency-associated lymphoproliferative disorders into view, which are often driven by EBV. The group of EBV-associated lymphoproliferative disorders includes different entities, with distinct biological features, ranging from indolent disorders, which may even spontaneously regress, to aggressive lymphomas requiring prompt and adequate treatment. These disorders are often diagnostically challenging due to their overlapping morphology and immunophenotype. Both nodal and extra-nodal sites, including the gastrointestinal tract, may be involved. This review, divided in three parts, summarizes the clinical, pathological, molecular features and treatment strategies of EBV-related lymphoproliferative disorders occurring in the gastrointestinal tract and critically analyzes the major issues in the differential diagnosis. In this part of the review, we discuss plasmablastic lymphoma, extra-cavitary primary effusion lymphoma and Burkitt lymphoma.

Multidisciplinary treatment of chronic active Epstein-Barr virus infection with multiple complications: a case report

Chronic active Epstein-Barr virus (CAEBV) infection is a very rare and potentially life-threatening illness caused by long-term EBV infection. Globally, the prevalence is the highest among young children and adolescents with increased frequency in Asians and Native Americans, whereas it is sporadically encountered in European countries. Typically, patients present with nonspecific symptoms such as fever, lymphadenopathy, hepatosplenomegaly, and liver dysfunction. However, the complications of CAEBV and its treatment are quite complex and require great care. We report a case of a 3-year-old boy with CAEBV infection who was later diagnosed with pancreatic mass and recurrent pancreatitis. A multidisciplinary board was consulted for correct diagnosis and treatment plan making. The treatment included pharmaceutical and surgical (duodenum-preserving pancreatic head resection) approaches. The patient showed tremendous improvement following the third discharge from the hospital and is still free of any symptoms. In this case report, we discuss differential diagnosis and comprehensively examined the possibility of the development of pancreatitis caused by EBV infection, the possibility of autoimmune pancreatitis, and the possibility of hereditary pancreatitis. To confirm or rule out the first two etiologies, laboratory and pathology results were studied. We also performed exon sequencing using Agilent exome capture kit to rule out hereditary pancreatitis. The clinical course of this disease and the way it was handled deserves attention so that similar cases receive prompt treatment.

Reframing Burkitt lymphoma: virology not epidemiology defines clinical variants

In 1964, Epstein-Barr virus (EBV) was identified in a biopsy from a patient with Burkitt lymphoma (BL) launching a new field of study into this ubiquitous human virus. Almost 60 years later, insights into the role of EBV in lymphomagenesis are still emerging. While all BL carry the hallmark c-myc translocation, the epidemiologic classification of BL (e.g., endemic, sporadic or immunodeficiency-associated) has traditionally been used to define BL clinical variants. However, recent studies using molecular methods to characterize the transcriptional and genetic landscape of BL have identified several unique features are observed that distinguish EBV+ BL including a high level of activation induced deaminase mutation load, evidence of antigen selection in the B cell receptor, and a decreased mutation frequency of TCF3/ID3, all found predominantly in EBV+ compared to EBV- BL. In this review, the focus will be on summarizing recent studies that have done in depth characterization of genetic and transcriptional profiles of BL, describing the differences and similarities of EBV+ and EBV- BL, and what they reveal about the etiology of BL. The new studies put forth a compelling argument that the association with EBV should be the defining etiologic feature of clinical variants of BL. This reframing of BL has important implications for therapeutic interventions for BL that distinguish the EBV+ from the EBV- lymphomas.

EBV-positive mucocutaneous ulceration

Ulceration of the oral cavity is common and a frequent reason for referral to secondary and tertiary centres. Epstein-Barr virus (EBV)-related mucocutaneous ulceration, however, is a rare cause of oral ulceration that has been described only recently. Histologically these lesions resemble lymphomas; however, their management and prognosis differ significantly. We present a case of EBV-induced oral ulceration and discuss the diagnosis and management of and available literature for the condition, which was treated successfully through conservative measures alone.