Chronic Active Epstein-Barr Virus Disease Research Articles

Highly sensitive detection of Epstein-Barr virus-infected cells by EBER flow FISH.

When Epstein-Barr virus (EBV) infection is suspected, identification of infected cells is important to understand the pathogenesis, determinine the treatment strategy, and predict the prognosis. We used the PrimeFlow™ RNA Assay Kit with a probe to detect EBV-encoded small RNAs (EBERs) and multiple surface markers, to identify EBV-infected cells by flow cytometry. We analyzed a total of 24 patients [11 with chronic active EBV disease (CAEBV), 3 with hydroa vacciniforme lymphoproliferative disorder, 2 with X-linked lymphoproliferative disease type 1 (XLP1), 2 with EBV-associated hemophagocytic lymphohistiocytosis, and 6 with posttransplant lymphoproliferative disorder (PTLD)]. We compared infected cells using conventional quantitative PCR methods and confirmed that infected cell types were identical in most patients. Patients with CAEBV had widespread infection in T and NK cells, but a small amount of B cells were also infected, and infection in patients with XLP1 and PTLD was not limited to B cells. EBV-associated diseases are believed to be complex pathologies caused by EBV infecting a variety of cells other than B cells. We also demonstrated that infected cells were positive for HLA-DR in patients with CAEBV. EBER flow FISH can identify EBV-infected cells with high sensitivity and is useful for elucidating the pathogenesis.

Single-Cell Transcriptomic Analysis of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis.

Epstein-Barr virus (EBV) infection can lead to infectious mononucleosis (EBV-IM) and, more rarely, EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), which is characterized by a life-threatening hyperinflammatory cytokine storm with immune dysregulation. Interferon-gamma (IFNγ) has been identified as a critical mediator for primary HLH; however, the detailed role of IFNγ and other cytokines in EBV-HLH is not fully understood. In this study, we used single-cell RNA sequencing to characterize the immune landscape of EBV-HLH and compared it with EBV-IM. Three pediatric patients with EBV-HLH with different backgrounds,one with X-linked lymphoproliferative syndrome type 1 (XLP1), two with chronic active EBV disease (CAEBV), and two patients with EBV-IM were enrolled. The TUBA1B + STMN1 + CD8 + T cell cluster, a responsive proliferating cluster with rich mRNA detection, was explicitly observed in EBV-IM, and the upregulation of SH2D1A-the gene responsible for XLP1-was localized in this cluster. This proliferative cluster was scarcely observed in EBV-HLH cases. In EBV-HLH cases with CAEBV, upregulation of LAG3 was observed in EBV-infected cells, which may be associated with an impaired response by CD8 + T cells. Additionally, genes involved in type I interferon (IFN) signaling were commonly upregulated in each cell fraction of EBV-HLH, and activation of type II IFN signaling was observed in CD4 + T cells, natural killer cells, and monocytes but not in CD8 + T cells in EBV-HLH. In conclusion, impaired responsive proliferation of CD8 + T cells and upregulation of type I IFN signaling were commonly observed in EBV-HLH cases, regardless of the patients' background, indicating the key features of EBV-HLH.

Clinical significance of anti-Epstein-Barr virus antibodies in systemic chronic active Epstein-Barr virus disease.

Systemic chronic active Epstein-Barr virus disease (sCAEBV) is a rare and fatal neoplasm, involving clonally proliferating Epstein-Barr virus (EBV)-infected T cells or natural killer cells. Patients with sCAEBV have abnormal titers of anti-EBV antibodies in their peripheral blood, but their significance is unknown. We retrospectively investigated titers and their relationship with the clinical features of sCAEBV using the data collected by the Japanese nationwide survey. Eighty-four patients with sCAEBV were analyzed. The anti-EBV nuclear antigen (EBNA) antibody, targeting EBNA-expressing EBV-positive cells, was found in 87.5% of children (<15 years old), 73.7% of adolescents and young adults (15-39 years old), and 100% of adults (≥40 years old). Anti-EBNA antibody titers were significantly lower and anti-VCA-IgG antibody titers significantly higher in patients with sCAEBV than those in healthy controls (p < 0.0001). Patients with high anti-VCA-IgG and anti-early antigen-IgG antibody (antibodies against the viral particles) levels had significantly better 3-year overall survival rates than those with low titers, suggesting that patients with sCAEBV have a reduced immune response to EBV-infected cells.

Chronic active Epstein-Barr virus disease originates from infected hematopoietic stem cells

AbstractChronic active Epstein-Barr virus (EBV) disease (CAEBV) is a lethal syndrome because of persistent EBV infection. When diagnosed as CAEBV, EBV infection was observed in multiple hematopoietic lineages, but the etiology of CAEBV is still elusive. Bone marrow and peripheral cells derived from 5 patients with CAEBV, 1 patient with EBV-associated hemophagocytic lymphohistiocytosis, and 2 healthy controls were analyzed. Multiple assays were applied to identify and characterize EBV-infected cells, including quantitative polymerase chain reaction, PrimeFlow, and single-cell RNA-sequencing (scRNA-seq). Based on scRNA-seq data, alterations in gene expression of particular cell types were analyzed between patients with CAEBV and controls, and between infected and uninfected cells. One patient with CAEBV was treated with allogeneic hematopoietic stem cell transplantation (HSCT), and the samples derived from this patient were analyzed again 6 months after HSCT. EBV infected the full spectrum of the hematopoietic system including both lymphoid and myeloid lineages, as well as the hematopoietic stem cells (HSCs) of the patients with CAEBV. EBV-infected HSCs exhibited a higher differentiation rate toward downstream lineages, and the EBV infection had an impact on both the innate and adaptive immunity, resulting in inflammatory symptoms. EBV-infected cells were thoroughly removed from the hematopoietic system after HSCT. Taken together, multiple lines of evidence presented in this study suggest that CAEBV disease originates from the infected HSCs, which might potentially lead to innovative therapy strategies for CAEBV.

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 ≥ 10,000IU/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 successful treatment for chronic active Epstein-Barr virus disease with Nephrotic Syndrome.

Chronic active Epstein-Barr virus (CAEBV) disease is more likely to occur when a patient is on immunosuppressive therapy for any disease or is susceptible to infection, and the prognosis is poor without appropriate treatment, including hematopoietic stem cell transplantation (HSCT). In addition to HSCT, several other chemotherapy regimens have been reported, but all of them are difficult to maintain in remission. Without HSCT, survival rates have been reported to be 50% in 5years and 25% in 15years. This is a report of a 13-year-old boy who developed CAEBV disease during cyclosporine A (CyA) treatment for the steroid-dependent nephrotic syndrome (SDNS). Since SDNS precluded HSCT or chemotherapy, CyA was tapered off based on the belief that alleviating his immunosuppressed state would decrease the CAEBV disease. We decided to gradually reduce the CyA dose to activate T-cell immunity, while periodically monitoring the EBV viral load. Finally, we found an appropriate dose that could suppress both CAEBV disease and SDNS, and it lasted for more than 9years. No case has been reported to date in which a patient developed CAEBV disease while receiving immunosuppressive drugs for the primary disease, and both diseases were controlled only by reducing the dose of immunosuppressive drugs. In this report, we show that dose reduction of immunosuppressive agents without chemotherapy or HSCT is an effective option for the treatment of CAEBV disease in patients receiving immunosuppressive agents.

Diagnostic and disease severity determination criteria for hydroa vacciniforme lymphoproliferative disorders and severe mosquito bite allergy.

Hydroa vacciniforme lymphoproliferative disorder (HV-LPD) and severe mosquito bite allergy (SMBA) are both cutaneous forms of Epstein-Barr virus (EBV)-associated T/natural killer (NK) cell LPDs and are closely related to chronic active EBV disease (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). HV-LPD is further divided into classic HV, a benign subtype mediated by EBV-positive γδT cells, and systemic HV, another life-threatening subtype mainly associated with EBV-positive αβT or γδT cells. The vast majority of patients with SMBA have increased numbers of EBV-infected NK cells in the blood. Clinical symptoms of HV-LPD and SMBA often overlap in the same patient and may progress to more serious disease conditions equivalent to the systemic form of CAEBV. To define the disease spectrum of HV-LPD and SMBA, we propose the diagnostic criteria and the determination criteria for disease severity. The proposed diagnostic criteria are consistent with those for CAEBV and EBV-HLH in the guidelines for the management for CAEBV and related disorders 2023.

Coexpression of natural killer cell antigens by T-cell large granular lymphocytes in hydroa vacciniforme lymphoproliferative disorder and the involvement of Vδ1 + epithelial-type γδT cells

Hydroa vacciniforme lymphoproliferative disorder (HV-LPD) is a cutaneous variant of chronic active Epstein–Barr virus disease. We examined the coexpression of T- and natural killer (NK)-cell antigens in five patients with classic HV (cHV) and five with systemic HV (sHV). T-cell receptor (TCR) repertoire analysis was performed with high‑throughput sequencing. All five cHV patients had increased γδT cells (> 5%), whereas five sHV patients showed γδT- and αβT-cell dominance in two patients each, and a mixture of abnormal γδT and αβT cells in one. Circulating CD3 + T cells expressed CD16/CD56 at 7.8–42.3% and 1.1–9.7% in sHV and cHV, respectively. The percentage of CD16/CD56 + T cells was higher in the large granular lymphocyte or atypical T-cell fractions in sHV, but no TCR Vα24 invariant chain characteristic of NKT cells was detected. Considerable numbers of CD3 + cells expressing CD56 were observed in sHV skin infiltrates. Of the circulating γδT cells tested, TCR Vδ1 + cells characteristic of the epithelial type of γδT cells were dominant in two sHV cases. Thus, atypical αβT and γδT cells in HV-LPD can express NK-cell antigens, such as CD16 and CD56, and Vδ1 + epithelial-type γδT cells are a major cell type in some HV-LPD cases.

Epstein-Barr virus: the molecular virology and the associated diseases.

Ever since its discovery as the first human oncogenic virus, Epstein-Barr virus (EBV) has been the focus of many researchers and is one of the best-studied pathogens. EBV is a major causative agent of Burkitt lymphoma, Hodgkin lymphoma, post-transplantation lymphoproliferative disorder, NK/T cell lymphoma, chronic active EBV disease, nasopharyngeal carcinoma, gastric carcinoma, and infectious mononucleosis. Although a truly comprehensive understanding of the virus and the associated disorders remains elusive, major breakthroughs in molecular cloning and omics analyses are shedding new light on this important virus. For example, EBV is now implicated in autoimmune diseases and neurodegenerative disorders. This review provides an overview of the molecular biology of EBV, the research history, the associated disorders, and the epidemiology.

Clinical and genetic characterization of Epstein-Barr virus–associated T/NK-cell lymphoproliferative diseases

Epstein-Barr virus (EBV)-associated T-/natural killer (T/NK)-cell lymphoproliferative diseases clinically take on various forms, ranging from an indolent course to an aggressive condition. Clinically, failure to establish precise diagnosis and provide proper treatment makes it difficult to help patients. We sought to better understand the underlying pathogenesis and to identify genetic prognostic factors to achieve better treatment efficacy. In this study, 119 cases of EBV-associated lymphoproliferative diseases, including EBV-associated hemophagocytic lymphohistiocytosis (n= 46) and chronic active EBV disease of T/NK cell type (n= 73), were retrospectively examined. Adults aged >20 years at onset accounted for 71.4% of our cohort. About 54.6% patients with unfavorable overall survival developed hemophagocytic lymphohistiocytosis and had higher plasma EBV load. Allogenic hematopoietic stem-cell transplantation was the sole independent favorable factor. We systematically screened germline and somatic aberrations by whole-exome and targeted sequencing. Among 372 antiviral immunity genes, germline variants of 8 genes were significantly enriched. From a panel of 24 driver genes, somatic mutations were frequently identified in dominant EBV-infected T/NK cells. Patients carrying any germline/somatic aberrations in epigenetic modifiers and RIG-I-like receptor (RLR) pathway had worse overall survival than those without 2 type aberrations. Importantly, patients with IFIH1 and/or DDX3X aberrations in the RLR pathway had higher plasma and NK-cell EBV load. Knockdown of DDX3X in NKYS cells downregulated RLR signaling activities and elevated the expression of EBV-encoded oncogenes such as LMP1 and EBNA1. Genetic defects were prevalent in adult EBV-associated hemophagocytic lymphohistiocytosis patients and patients with chronic active EBV disease of T/NK cell type; these defects were associated with unfavorable prognosis. These findings can help clinicians work out more precise staging of the condition and provide new insights into these EBV-associated diseases.

Natural killer cell memory precedes HLH in monozygotic twins discordant for chronic active Epstein-Barr virus disease

Severe mosquito bite allergy (SMBA) is a manifestation of chronic active Epstein-Barr virus (CAEBV) infection defined by necrotic ulceration of the stings. CAEBV with SMBA has a high mortality rate as most patients eventually develop fulminant and refractory hemophagocytic lymphohistiocytosis (HLH). However, how self-resolving SMBA escalates to systemic lethal HLH remains unclear. Through comprehensive immune profiling of a SMBA patient with CAEBV and her healthy monozygotic twin, we found that both twins were seropositive for EBV but showed high discordance in their circulating natural killer (NK) cells. The patient's EBV-infected NK cells displayed memory-like properties, including low CD16, high CD226 and induction of enhanced IFNγ production by IL-2 or IL-12. Her leukocytes also produced high levels of IL-2 and IL-12 when stimulated with salivary gland extract (SGE) specifically from A. albopictus mosquitoes, connected again with hyperproduction of IFNγ by her NK cells. Strikingly, pharmacological inhibition of STAT3 suppressed the NK memory-associated cytokine axis of IFNγ, IL-2 and IL-12 that is generated by A. albopictus SGE stimulation. Altogether, this study shows that NK memory is promoted during CAEBV with SMBA by repeated cytokine restimulation leading up to lethal HLH, and proposes STAT3 as a therapeutic target to halt its progression.

Diagnosis and management of EBV-positive lymphoproliferative disorders

Epstein-Barr virus (EBV) has the ability to immortalize not only B cells but also T and natural killer (NK) cells. The virus may also contribute to the onset of EBV-positive lymphoproliferative disorders (EBV-LPDs) by inducing the introduction of gene mutations. It is known that B cell EBV-LPDs (B-EBV-LPDs) develop with preexisting immunodeficiency, but the onset mechanism of T cell and NK cell EBV-LPDs (T-EBV-LPDs and NK-EBV-LPDs), also known as chronic active EBV disease and associated diseases, is unclear. The diagnosis of both EBV-LPDs requires the quantitative examination of EBV-DNA in the peripheral blood. Eliminating the cause of immunodeficiency or administering rituximab is effective in treating B-EBV-LPDs, but some B-EBV-LPDs and T-EBV-LPDs/NK-EBV-LPDs are resistant to pharmacotherapy. Therefore, further research is needed to explicate the pathophysiology of EBV-LPDs and develop a drug for its treatment.

Phase II Study of a JAK1/2 Inhibitor Ruxolitinib for Systemic Chronic Active Epstein-Barr Virus Disease: An Investigator-Initiated Trial

Background: Systemic chronic active Epstein-Barr virus disease (sCAEBV) is a rare EBV-positive T- or NK-lymphoproliferative disease. Although the only curative treatment for sCAEBV available now is allogeneic hematopoietic stem cell transplantation (allo-HSCT), the presence of disease activity, persistent inflammation, at the time of allo-HSCT is associated with poor outcomes (Am J Hem.2022, 97, p780). STAT3 is constitutively activated contributing to cytokine production and cell survival of EBV-infected cells in sCAEBV (Oncotarget. 2019, 9, p31077). Thus, STAT3 inhibition by ruxolitinib, a JAK1/2 inhibitor, may be effective against disease activity of sCAEBV. Methods: We conducted an investigator-initiated trial of open-label, phase 2, prospective and multicenter to assess the efficacy and safety of ruxolitinib in sCAEBV patients with disease activity. The diagnostic criteria were as follows: elevated EBV-DNA load in the peripheral blood (PB) (>102.5 copies/µg DNA); EBV infected T or NK cells detected in affected tissues or PB; systemic inflammatory symptoms persisting for more than three months; exclusion of other possible diagnoses, such as immune deficiencies, autoimmune diseases, or lymphoma (Blood adv. 2021, 4, p2918). sCAEBV patients ≥13 y.o. with fever (≥ 37.5 ºC), and/or liver dysfunction (ALT ≥ 2.0 × ULN) were enrolled. Anti-VCA-IgM-positive patients were excluded. The initiation dose of ruxolitinib was 5-20 mg twice a day determined by the platelet count in PB. The treatment effects were classified as complete response (CR), partial response (PR), progressive disease (PD), and stable disease (SD). CR was defined as the disappearance of all the elements of disease activity such as fever, liver dysfunction, uveitis, progressive skin lesions, and vasculitis. PR was defined as the disappearance of at least one of the elements listed above. PD was defined as the conversion to active disease, exacerbation of active disease, or the development of overt T- or NK-cell lymphoma. SD was defined as presenting no progression. Ruxolitinib was administered for eight weeks. If CR was observed and allo-HSCT was scheduled, ruxolitinib was terminated early even if these events had occurred within less than eight weeks after initiating investigational drug administration. The primary endpoint of efficacy assessments was CR rate at eight weeks after the initiation of drug administration or at the time of early termination. Safety was assessed based on the frequency of adverse events defined by Common Terminology Criteria for Adverse Events, version 4.0. Results: Nine patients were enrolled between January 2019 and August 2021; five males and four females aged 13-64 y.o.; median age of 40 y.o. The types of EBV-infected cells were as follows: four were CD4, one was CD8, and four were CD56. Seven patients completed the study. Five among them received ruxolitinib for eight weeks and were treated as outpatients. Two patients fulfilled the criteria of early termination and each was treated for 35 and 12 days. The responses are shown in the figure. CR rate and OR rate after eight weeks or at early termination, the primary and the secondary endpoints were 28.6% (2/7) and 42.9% (3/7), respectively. No one showed progressive disease. One patient developed a grade 4 adverse event of oral bleeding during the treatment and resulted in discontinuing the administration of ruxolitinib on day 13. Seven patients received allo-HSCT. Five patients achieved undetectable level of EBV-DNA PB after allo-HSCT. Conclusion: The results indicate that ruxolitinib has demonstrated encouraging effects and is a potent therapeutic reagent against sCAEBV with active disease. Further analysis shall complete its assessment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

High risk of relapsed disease in patients with NK/T-cell chronic active Epstein-Barr virus disease outside of Asia

AbstractChronic active Epstein-Barr virus (EBV) disease (CAEBV) is characterized by high levels of EBV predominantly in T and/or natural killer cells with lymphoproliferation, organ failure due to infiltration of tissues with virus-infected cells, hemophagocytic lymphohistiocytosis, and/or lymphoma. The disease is more common in Asia than in the United States and Europe. Although allogeneic hematopoietic stem cell transplantation (HSCT) is considered the only curative therapy for CAEBV, its efficacy and the best treatment modality to reduce disease severity prior to HSCT is unknown. Here, we retrospectively assessed an international cohort of 57 patients outside of Asia. Treatment of the disease varied widely, although most patients ultimately proceeded to HSCT. Though patients undergoing HSCT had better survival than those who did not (55% vs 25%, P < .01), there was still a high rate of death in both groups. Mortality was largely not affected by age, ethnicity, cell-type involvement, or disease complications, but development of lymphoma showed a trend with increased mortality (56% vs 35%, P = .1). The overwhelming majority (75%) of patients who died after HSCT succumbed to relapsed disease. CAEBV remains challenging to treat when advanced disease is present. Outcomes would likely improve with better disease control strategies, earlier referral for HSCT, and close follow-up after HSCT including aggressive management of rising EBV DNA levels in the blood.

Interferon alpha as antiviral therapy in chronic active Epstein-Barr virus disease with interstitial pneumonia - case report

BackgroundChronic active Epstein-Barr virus (EBV) disease (CAEBV) is defined as a severe, progressive lymphoproliferative disorder associated with active EBV infection persisting longer than 6 months and developing in patients without recognised immunodeficiency. Rarely, interstitial pneumonitis (IP) occurs as a serious complication in CAEBV patients. The standard therapeutic regimen for IP in CAEBV has not yet been defined. Although interferon alpha (IFN-alpha) is known to suppress viral DNA replication by affecting its basal promoter activation process, it is rarely used in CAEBV patients.Case presentationA 22-year-old Caucasian woman, diagnosed with CAEBV 1.5 years earlier, was admitted to the Immunology Clinic due to a 4-week history of productive cough, fever and general weakness. Cultures of blood, urine and sputum were negative, but EBV DNA copies were found in the sputum, whole blood, isolated peripheral blood lymphocytes as well as in the blood plasma. Cytokine assessment in peripheral blood revealed the lack of IFN-alpha synthesis. Disseminated maculate infiltrative areas in both lungs were observed on a computed tomography (CT) chest scan. The patient was not qualified for the allogeneic hematopoietic stem cell transplantation (allo-HSCT) due to the risk of immunosuppression-related complications of infectious IP. Inhaled (1.5 million units 3 times a day) and subcutaneous (6 million units 3 times a week) IFN-alpha was implemented. To the best of our knowledge, this was the first documented use of inhaled IFN-alpha in a patient with CAEBV and concomitant IP. Patient’s status has improved, and she was eventually qualified to allo-HSCT with reduced conditioning. Currently, the patient feels well, no EBV was detected and further regression of pulmonary changes was documented.ConclusionsCAEBV should be considered in patients who present with interstitial lung infiltration and involvement of other organs. Although more promising results have been obtained with allo-HSCT, inhaled IFN-alpha may also be a therapeutic option in patients with CAEBV and a concomitant IP.

The clinical characteristics and the features of immunophenotype of peripheral lymphocytes of adult onset chronic active Epstein-Barr virus disease at a Tertiary Care Hospital in Beijing.

Chronic active Epstein-Barr virus (CAEBV) infection is a rare disease with high mortality. Most of CAEBV patients have been reported from Japan and are pediatric cases.The goal was to describe the clinical characteristics and the immunophenotypic features of peripheral lymphocytes in adult onset CAEBV patients.We retrospectively reviewed and analyzed all adult onset CAEBV cases admitted to Peking Union Medical College Hospital (PUMCH) between 2012 and 2016. Demographic, clinical, laboratory data, and the immunophentyping data of peripheral lymphocytes were collected.There were 28 adult onset CAEBV patients. The median age was 45 (range, 20–81). Most of the patients presented with fever; splenomegaly; lymphadenopathy and hepatitis. Unlike pediatric cases reported, the manifestations of cardiovascular diseases in our patients were pulmonary arterial hypertension, decreased cardiac function and aorta vasculitis. Prevalence of interstitial pneumonitis in our patients were comparatively higher and prevalence of hypersensitivity to mosquito bites were comparatively lower than that reported by Japan. In this study, CAEBV patients had decreased B cell, NK cell, CD4 cell and CD8 cell counts. The prevalence of low level of B cells, NK cells, CD4 cells was relatively higher than reported ever.Chinese adult onset CAEBV patients have different clinical characteristics and are featured by an immunosuppression status as demonstrated by decreased B cell, NK cell, CD4 cell and CD8 cell.

Chronic Active Epstein-Barr Virus Disease.

Chronic active Epstein–Barr virus (CAEBV) disease is a rare disorder in which persons are unable to control infection with the virus. The disease is progressive with markedly elevated levels of EBV DNA in the blood and infiltration of organs by EBV-positive lymphocytes. Patients often present with fever, lymphadenopathy, splenomegaly, EBV hepatitis, or pancytopenia. Over time, these patients develop progressive immunodeficiency and if not treated, succumb to opportunistic infections, hemophagocytosis, multiorgan failure, or EBV-positive lymphomas. Patients with CAEBV in the United States most often present with disease involving B or T cells, while in Asia, the disease usually involves T or NK cells. The only proven effective treatment for the disease is hematopoietic stem cell transplantation. Current studies to find a cause of this disease focus on immune defects and genetic abnormalities associated with the disease.

GATA2 Deficiency and Epstein-Barr Virus Disease.

GATA2 is a transcription factor that binds to the promoter of hematopoietic genes. Mutations in one copy of the gene are associated with haploinsufficiency and reduced levels of protein. This results in reduced numbers of several cell types important for immune surveillance including dendritic cells, monocytes, CD4, and NK cells, as well as impaired NK cell function. Recently, GATA2 has been associated with several different presentations of severe Epstein–Barr virus (EBV) disease including primary infection requiring repeated hospitalizations, chronic active EBV disease, EBV-associated hydroa vacciniforme with hemophagocytosis, and EBV-positive smooth muscle tumors. EBV was found predominantly in B cells in each of the cases in which it was studied, unlike most cases of chronic active EBV disease in which the virus is usually present in T or NK cells. The variety of EBV-associated diseases seen in patients with GATA2 deficiency suggest that additional forms of severe EBV disease may be found in patients with GATA2 deficiency in the future.

Association of GATA2 Deficiency With Severe Primary Epstein-Barr Virus (EBV) Infection and EBV-associated Cancers.

Most patients infected with Epstein-Barr virus (EBV) are asymptomatic, have nonspecific symptoms, or have self-limiting infectious mononucleosis. EBV, however, may result in severe primary disease or cancer. We report EBV diseases associated with GATA2 deficiency at one institution and describe the hematology, virology, and cytokine findings. Seven patients with GATA2 deficiency developed severe EBV disease. Three presented with EBV infectious mononucleosis requiring hospitalization, 1 had chronic active EBV disease (B-cell type), 1 had EBV-associated hydroa vacciniforme-like lymphoma with hemophagocytic lymphohistiocytosis, and 2 had EBV-positive smooth muscle tumors. Four of the 7 patients had severe warts and 3 had disseminated nontuberculous mycobacterial infections. All of the patients had low numbers of monocytes, B cells, CD4 T cells, and natural killer cells. All had elevated levels of EBV in the blood; 2 of 3 patients tested had expression of the EBV major immediate-early gene in the blood indicative of active EBV lytic infection. Mean plasma levels of tumor necrosis factor α, interferon γ, and interferon gamma-induced protein 10 were higher in patients with GATA2 deficiency than in controls. GATA2 is the first gene associated with EBV hydroa vacciniforme-like lymphoma. GATA2 deficiency should be considered in patients with severe primary EBV infection or EBV-associated cancer, especially in those with disseminated nontuberculous mycobacterial disease and warts.

Mature T- and NK-cell non-Hodgkin lymphoma in children and young adolescents.

Mature T/Natural killer (NK)-cell neoplasms of children and the young adolescent population exhibit higher prevalence in Central and South American and Asian populations and many are associated with Epstein-Barr virus (EBV). They are represented in large part by extranodal T/NK cell lymphomas- nasal-type or extra nasal-type, chronic lymphoproliferative disorders of T/NK cells or chronic active EBV disease, systemic EBV-positive lymphoproliferative disorders of childhood, hydroa vacciniforme-like lymphoma, hepatosplenic T-cell lymphoma and primary cutaneous gamma/delta T-cell lymphoma among others. Many T/NK cell neoplasms in this age group are derived from cells of the innate immune system, in contrast to adults where they are predominantly from the adaptive immune system. The genetic basis of T/NK cell lymphomas in children and young adolescents remains largely unknown. Anthracycline-based regimens and haematopoietic stem cell transplants (allogeneic and autologous) are current treatment modalities, however it is anticipated that novel targeted therapeutic agents will be available in the near future.