From Burkitt's lymphoma to chronic active Epstein-Barr virus (EBV) infection: an expanding spectrum of EBV-associated diseases

Epstein-Barr virus (EBV) is one of 8 known human herpesviruses. EBV infection usually occurs in early childhood and is subclinical. However, primary infection in adolescence or adulthood causes infectious mononucleosis in approximately half of infected individuals. Recently, the spectrum of human diseases associated with EBV infection has increased, primarily due to methodological advances in EBV detection. Initially, EBV was isolated from a cultured Burkitt lymphoma cell line, and has been felt to be etiologically linked to the development of Burkitt lymphoma, as well as other human malignancies. This review mainly focuses on pathogenetic mechanisms, many of which remain enigmatic, for the various human diseases, which are considered to be associated with EBV infection.     

Epstein-Barr virus infection and associated diseases in children

Epstein-Barr virus (EBV), an ubiquitous human B lymphotropic virus, is the cause of infectious mononucleosis. Moreover, EBV infection can be followed by lymphoproliferative diseases in patients with inherited and acquired immunodeficiencies. Primary EBV infection may be a threat to all children after marrow or organ transplantation or those receiving chronic immunosuppressive treatment for various other reasons. The virus has been also implicated in the pathogenesis of different malignant tumours such as Burkitt lymphoma, nasopharyngeal carcinoma, Hodgkin disease and some T-cell lymphomas. This review focuses on various aspects of virus-host interactions, immune mechanisms of the host, and the still experimental therapeutic approaches in EBV-associated diseases.     

Epstein-Barr virus infection and associated diseases in children

Epstein-Barr virus (EBV), an ubiquitous human B lymphotropic virus, is the cause of infectious mononucleosis. Moreover, EBV infection can be followed by lymphoproliferative diseases in patients with inherited and acquired immunodeficiencies. Primary EBV infection may be a threat to all children after marrow or organ transplantation or those receiving chronic immunosuppressive treatment for various other reasons. The virus has been also implicated in the pathogenesis of different malignant tumours such as Burkitt lymphoma, nasopharyngeal carcinoma, Hodgkin disease and also some T-cell lymphomas. This review focuses on various aspects of virus-host interactions, immune mechanisms of the host, and the still experimental therapeutic approaches in EBV-associated diseases.     

Epstein-Barr virus infection and its role in the expanding spectrum of human diseases

Recent advances of the various laboratory tests to detect Epstein-Barr virus (EBV) infection have clarified the causative role for a spectrum of EBV-associated diseases. They include lymphoproliferative disorders (LPD), which occur in immunologically compromised individuals, Hodgkin's disease (HD), chronic active EBV infection (CAEBV), virus-associated hemophagocytic syndrome (VAHS), certain forms of T cell lymphoma, and some gastric carcinomas, in addition to the classical EBV-associated diseases such as EBV genome-positive Burkitt's lymphoma (BL), undifferentiated nasopharyngeal carcinoma (NPC) and infectious mononucleosis (IM). This review intends to introduce the recent progress of studies on EBV infection mainly from the clinical points of view.     

EB病毒亚型/变异株及其与疾病关系的研究进展

Epstein-Barr病毒(Epsteir-Barr virus,EBV)属于疱疹病毒科γ亚科,与鼻咽癌、地方性伯基特淋巴瘤和霍奇金淋巴瘤等相关,是重要的肿瘤相关病毒.EBV基因组中存在多个多态性区域,根据这些区域中氨基酸的变异,可将EBV分为不同的亚型/变异株.目前,关于不同EBV亚型/变异株与疾病间是否相关尚无定...     

Immunodeficiency as a factor in lymphomagenesis

The human immune system has evolved multiple cellular and humoral defense mechanisms against the lymphotropic virus, EBV. NK cells, suppressor T-cells, cytotoxic K-cells, memory T-cells, and humoral immune responses usually subdue the virus into latency. Individuals with immune deficiency are at great risk of developing immunoregulatory disturbances and lymphoproliferative diseases when confronted by EBV. The infection of B-cells by EBV provokes a marked activation of immunoregulatory T-cells and requires restoration of immune homeostasis during convalescence. This is accomplished with difficulty in an individual with significant immune defects. The X-linked lymphoproliferative syndrome is an exemplary model for studying EBV in immune deficient individuals. Boys with XLP can develop acquired agammaglobulinemia, aplastic anemia, chronic or fatal IM, and a variety of B-cell malignant lymphomas following infection by the virus. We have identified multiple immune defects in the patients and progressive immunoregulatory disturbances following infection by the virus. Other patients with immune deficiency syndromes, i.e., ataxia telangiectasia or the renal transplant recipient, are also at increased risk for developing EBV-induced lymphoproliferative diseases. Moreover, certain families are at increased risk for EBV-associated malignancies, especially those with a triad of manifestations (i.e., autoimmunity, immunodeficiency, and lymphoma). Chromosomal breakage as seen in patients with ataxia telangiectasia may predispose to leukemogenesis. Immunoregulatory defects are also probably predisposing factors to lymphomagenesis. Both inherited and acquired defects can render persons vulnerable to leukemia and lymphoma.     

Persistent Low Level Epstein-Barr Virus DNAemia in Childhood Cancer Survivors

Background: Clinical observation of Epstein-Barr virus (EBV) status has not documented in childhood cancer survivors (CCSs) sustaining long-term remission of malignant diseases. Thus, the aim of this study was to evaluate the EBV status in children with various malignant diseases after they completed their treatments. Patients and Methods: Thirty consecutive children with various malignant diseases previously received treatment at the University of Tsukuba Hospital. Nine cases had acute lymphoblastic leukemia (ALL), 10 had solid tumors, 4 had lymphoma, 4 had CNS tumors, and 3 had acute myeloid leukemia (AML). EBV DNA in 328 whole blood samples were monitored by real-time QPCR for all cases after treatment. Clinical records and laboratory data were also reviewed. Results: There were 6/30 (20%) cases with continuous detection of EBV DNA while there were 24/30 (80%) cases without continuous EBV DNA. EBV DNAemia was persistently observed in 4/9 (44.4%) cases with ALL and in 2/4 (50%) cases with lymphoma. Persistent EBV DNAemia can be observed for >5 years without any EBV associated symptoms or diseases. Conclusions: Childhood cancer survivors have persistent EBV DNAemia more frequently, which is thought to be observed in cases with ALL and lymphoma with higher tendency for >5 years after treatment. Persistent EBV DNAemia is frequent in CCSs aged 5–10 years. Any immunological alteration is speculative in a pathophysiology of persistent EBV DNAemia.     

X-连锁淋巴细胞异常增生症一例及其家系基因和蛋白表达研究

目的 探讨1例中国X-连锁淋巴细胞异常增生症(XLP)患儿及其家系的临床特征、基因突变和外周血单个核细胞(PBMC)SAP蛋白表达.方法 患儿男,6岁,于5岁时发现右腰部肿物,活检提示为伯基特淋巴瘤.其胞兄及表兄均于1岁左右因重症传染性单核细胞增多症夭折.据临床表现、家族史、免疫学特征拟诊为XLP.提取患儿及部分亲属基因组DNA,采用PCR法扩增SH2D1A基因,PCR产物直接进行双向序列测定,采用流式细胞仪检测PBMC中SAP蛋白表达.结果 患儿在缓解期EBV-DNA检测为536.9拷贝/ml(＞500拷贝/ml为EBV阳性),其SH2D1A基因第2外显子462位核苷酸发生无义突变,碱基C突变为T,形成TGA终止密码子(Arg55X),患儿母亲、姨母及外祖母为该突变携带者.患儿PBMC中SAP蛋白表达水平明显下降,而携带者SAP蛋白表达未见异常.结论 通过临床及实验室检查,确诊1例XLP患儿及家系.男性重症EBV感染,甚或无EB病毒感染证据,但具有家族史的淋巴瘤患儿应考虑XLP.SAP蛋白流式细胞仪检测为快速、准确的诊断手段.

Abstract：

Objective X-linked lymphopmliferative disease(XLP),a genetic disorder characterized by immunodeficiency to Epstein-Barr virus(EBV)infection,has been linked to mutations in the SH2D1 A gene.XLP patient displays EBV associated fulminant infectious mononucleosis or hemophagocytie lymphohistocytosis,hypogammaglobulinemia or malignant lymphoma.Here we report the clinical features.gene mutation and SAP expression on PBMCs of a Chinese patient with XLP and potential carriers.Method A 6 years old male patient and his maternal relatives were enrolled in this study.The patient was found to have with a renal Burkitt lymphoma on the right waist at 5 years of age by accident.His elder brother and a maternally related cousin botIl died of multiple systemic organ dysfunction syndrome (MODS)due to fulminant infectious mononucleosis(FIM)at the age of one year.The patient and his maternal relatives were subjected to detection of SAP expression on the PBMCs by flow cytometry and gene mutation analysis of SH2D1A by using PCR based on genomic DNA.Result The patient exhibited 536.9copy/ml level of circulating EBV-DNA during remission.Sequence analysis showed that the patient harbored a nonsense mutation in exon 2(C462T),resulting in a premature stop codon(Arg55X).His mother and some of the matemal relatives were proved to be carriers of this mutation.SAP expression from the patient was significantly reduced as compared to normal individual and the carriers.Conclusion We identified a Chinese XLP ease genetically.Assessment of SAP expression on PBMCs by flow cytometry seemed to be an effective rapid diagnostic method for this disease.Absence of EBV infeetion does not diminish the possibility of XLP.     

X-连锁淋巴细胞异常增生症一例及其家系基因和蛋白表达研究

目的 探讨1例中国X-连锁淋巴细胞异常增生症(XLP)患儿及其家系的临床特征、基因突变和外周血单个核细胞(PBMC)SAP蛋白表达.方法 患儿男,6岁,于5岁时发现右腰部肿物,活检提示为伯基特淋巴瘤.其胞兄及表兄均于1岁左右因重症传染性单核细胞增多症夭折.据临床表现、家族史、免疫学特征拟诊为XLP.提取患儿及部分亲属基因组DNA,采用PCR法扩增SH2D1A基因,PCR产物直接进行双向序列测定,采用流式细胞仪检测PBMC中SAP蛋白表达.结果 患儿在缓解期EBV-DNA检测为536.9拷贝/ml(＞500拷贝/ml为EBV阳性),其SH2D1A基因第2外显子462位核苷酸发生无义突变,碱基C突变为T,形成TGA终止密码子(Arg55X),患儿母亲、姨母及外祖母为该突变携带者.患儿PBMC中SAP蛋白表达水平明显下降,而携带者SAP蛋白表达未见异常.结论 通过临床及实验室检查,确诊1例XLP患儿及家系.男性重症EBV感染,甚或无EB病毒感染证据,但具有家族史的淋巴瘤患儿应考虑XLP.SAP蛋白流式细胞仪检测为快速、准确的诊断手段.     

Diagnosis and treatment of post-transplantation lymphoproliferative disorder in pediatric heart transplant patients

PTLD is a severe complication in transplant recipients. Detection of increased EBV load in the peripheral blood acts as a surrogate marker for increased risk of PTLD development. We analyzed the time course of the disease, its severity, the organs involved, and mortality rates in our institutional experience of pediatric heart transplantation. This paper identifies risk factors for PTLD and describes the different ways of diagnosing and treating the disease. PTLD was screened for in 146 pediatric heart transplant patients using a retrospective analysis in patients who received transplantation before 1998. Prospective determination was performed in 72/146 patients transplanted after 1998 within the post-transplant follow-up. The occurrence of PTLD with all interventions, including tapering of immunosuppression, surgery, viral monitoring, and antiviral interventions, was recorded. PTLD was diagnosed in 12/147 (8.2%) children at a mean age of 7.2 +/- 3.3 yr after a mean post-transplant period of 3.2 +/- 2.2 yr. PTLD manifested in: lymph nodes (n = 4), intestine (n = 3), tonsils and adenoids (n = 2), eye (n = 2), and lung (n = 1). It was diagnosed in 7/12 as a monomorphic B-cell lymphoma and in four patients as a monomorphic Burkitt lymphoma, a polymorphic B-cell lymphoma, a T-cell rich or angiocentric lymphoma (Liebow) and as reactive plasmacytic hyperplasia (early lesion), respectively. Histology was not possible in one patient with ocular manifestation. EBV association was 83%. Risk factors in the comparison with patients without PTLD were age at time of Tx, primary EBV infection after Tx, use of Azathioprine and >or=3 doses of ATG. CMV mismatch and CMV infection, rejection episodes and steroids were not risk factors. Despite reduction of immunosuppression, treatment consisted of surgical procedures to remove tumor masses (n = 6), Rituximab (n = 5), polychemotherapy (n = 3), antiviral (n = 1) and autologous T-cell therapy (n = 1). All patients demonstrated full remission without death related to PTLD or treatment at 3.9 (1.3-6.2) yr median follow-up time. The manifestation of PTLD in pediatric heart transplant recipients is associated with EBV infection and is predominantly in the form of a B-cell lymphoma. A tight and specific follow-up including early assessment of immunity status and specific therapeutic intervention to improve cellular immunity is warranted and may contribute to a significant reduction of PTLD-related morbidity and mortality.     

Infiltrations of Epstein-Barr virus-carrying cells in granular lymphocyte-proliferative disorders corresponding to chronic active Epstein-Barr virus infection

A 21-year-old man with granular lymphocyte-proliferative disorders (GLPD) associated with chronic active Epstein-Barr virus (EBV) infection is described. Chromosomal analyses revealed several clonal abnormalities and two of them were mainly repetitious. High copy numbers of monoclonal EBV genome were also detected in the proliferative large granular lymphocytes (LGLs), indicating the monoclonal expansion of EBV-infected LGLs. The patient had an indolent course for several years, and there was no evidence of infiltrations of his bone marrow until the end stage. At autopsy, microscopic studies revealed marked infiltrations of LGL in the liver and spleen, and the infiltrating cells were NK-cell immunophenotype. The infiltrated LGLs showed latency I.     

EB病毒相关性肿瘤疾病

EB病毒（EBV）是一种能诱发肿瘤的疱疹病毒。近年来,有关EBV在人体内生存的机制、感染后的免疫调控、相关疾病的发病机制等方面均有了新的认识。现就近年来EBV相关性肿瘤的研究进展情况进行介绍。     

Subsequent development of diffuse large B-cell lymphomas and Hodgkin lymphoma associated with primary immune disorder in a 6-year-old female: a case report and review of the literature

Neoplastic lymphoid proliferation may arise from immune deficiency or disordered regulation of the immune system. Often the neoplasms are associated with viral agents, such as Epstein-Barr virus, human immunodeficiency virus, or human herpes virus 8. Lymphoproliferative diseases have been documented in a variety of primary immune disorders. The most commonly encountered neoplastic lesion is diffuse large B-cell lymphoma (DLBCL), although Hodgkin lymphoma (HL), Burkitt lymphoma, and peripheral T-cell lymphomas and/or leukemias have also been documented in rare instances. We report a case of a 6-year-old girl with unclassifiable primary immunodeficiency diagnosed with 2 different clones of DLBCLs and subsequently developed lymphocyte-depleted, classical HL. Both neoplasms were associated with Epstein-Barr virus. To the best of our knowledge, this is the first reported occurrence of primary immune disorder-associated lymphoproliferative disease with sequential development of DLBCLs and HL in a pediatric patient. Thorough surveillance is paramount for accurate assessment of the associated lymphoproliferative disease and in ascertaining likely transformation to, or de novo evolution of a different lymphoid neoplasm. This is also important in evaluating treatment response with appropriate therapeutic adjustments if clinically indicated.     

EB病毒相关性肿瘤疾病

EB病毒(EBV)是一种能诱发肿瘤的疱疹病毒.近年来,有关EBV在人体内生存的机制、感染后的免疫调控、相关疾病的发病机制等方面均有了新的认识.现就近年来EBV相关性肿瘤的研究进展情况进行介绍.     

Chromosomes and causation of human cancer and leukemia: XXXVI. The 14q+ anomaly in an American Burkitt lymphoma and its value in the definition of lymphoproliferative disorders.

A case of a 10-year-old boy with American Burkitt lymphoma is presented in whom a 14q+ due to t(8;14)(q23;q32) was shown to exist in the ascitic lymphoma cells. This appears to be the first demonstration of such a translocation in uncultured material. In addition, another translocation involving the X chromosome, hitherto not observed in Burkitt tumors, was demonstrated. The karyotypic findings have been related to the cytogenetic experience in Burkitt and other lymphomas, with emphasis being put on the importance of the 14q+ anomaly in lymphoproliferative diseases.     

91例EB病毒相关疾病儿童血浆EB病毒DNA的检测

目的了解EB病毒(EBV)感染患儿外周血血浆中游离EBVDNA的拷贝数,确定EBV原发感染后外周血血浆中EBV游离DNA的拷贝数与发病天数及病情轻重的关系。方法应用荧光定量PCR方法,测定73例EBV原发感染和18例EBV相关重症疾病患儿外周血血浆中EBV游离DNA。结果①原发EBV感染患儿外周血血浆中EBV游离DNA随发病天数呈下降趋势,发病2周后很难检测到。②EBV相关重症疾病组患儿外周血血浆中EBV游离DNA阳性率明显高于原发EBV感染组,差异有显著性(89%vs16%,P<0.05)。结论原发EBV感染后随病程天数的增加,病毒复制水平逐渐下降。血浆中EBV游离DNA检测对评价EBV相关疾病的严重程度有一定参考价值。     

Chromosomes and causation of human cancer and leukemia: XXXVI. The 14q+ anomaly in an american burkitt lymphoma and its value in the definition of lymphoproliferative disorders

A case of a 10-year-old boy with American Burkitt lymphoma is presented in whom a 14q+ due to t(8;14)(q23;q32) was shown to exist in the ascitic lymphoma cells. This appears to be the first demonstration of such a translocation in uncultured material. In addition, another translocation involving the × chromosome, hitherto not observed in Burkitt tumors, was demonstrated. The karyotypic findings have been related to the cytogenetic experience in Burkitt and other lymphomas, with emphasis being put on the importance of the 14q+ anomaly in lymphoproliferative diseases.     

High-dose therapy and autologous stem cell transplantation for children with HIV-associated non-Hodgkin lymphoma

In contrast to adults, autologous stem cell transplantation (ASCT) as part of the salvage strategy after high-dose chemo/radiotherapy in human immunodeficiency virus (HIV) related Non-Hodgkin lymphoma (NHL) is not yet established for children. We report on a 13-year patient with congenital HIV infection and refractory Burkitt lymphoma, who was successfully treated by high-dose therapy (HDT) including rituximab followed by ASCT. After 26 months follow-up the patient remains in complete remission and his HIV parameters have normalized with continued highly active antiretroviral therapy (HAART). HIV infection may no longer exclude children from ASCT as part of salvage therapy.     

Epstein-Barr Virus in Non-Hodgkin's Lymphomas and Lymphoid Tissue in Children

In developed countries the majority of adolescent children show serological evidence of past Epstein-Barr virus (EBV) infection. This virus is associated with non-Hodgkin's lymphomas in immunocompromised children, but the relationship of EBV DNA to these tumors in children without documented immunodeficiency has not been investigated by the polymerase chain reaction (PCR). We used a PCR method with primers from the Bam W and Bam HI regions to study non-Hodgkin's lymphomas in children, with tonsillar tissue of age-matched children as controls for the presence of EBV DNA. Six of the 20 tonsils were positive using the Bam W primers; another four showed this DNA with Bam HI primers. EBV DNA was detected in only one tumor (a lymphoblastic lymphoma) by both primer sets. The demonstration of EBV DNA in the tonsils reflects past infections and the incidence is in accordance with that expected from serologic epidemiologicl studies. The absence of demonstrable EBV DNA in 19 lymphomas suggests that this virus is of little consequence in the pathogenesis of non-Hodgkin's lymphomas in children who are not known to be immunocompromised. The lymphoblastic lymphoma had a mixed cell population, and the virus was not necessarily related to the malignancy.     

91例EB病毒相关疾病儿童血浆EB病毒DNA的检测

目的:了解EB病毒（EBV）感染患儿外周血血浆中游离EBV DNA的拷贝数,确定EBV原发感染后外周血血浆中EBV游离DNA的拷贝数与发病天数及病情轻重的关系。方法:应用荧光定量PCR方法,测定73例EBV原发感染和18例EBV相关重症疾病患儿外周血血浆中EBV游离DNA。结果:①原发EBV感染患儿外周血血浆中EBV游离DNA随发病天数呈下降趋势,发病2周后很难检测到。②EBV相关重症疾病组患儿外周血血浆中EBV游离DNA阳性率明显高于原发EBV感染组,差异有显著性(89% vs 16%, P＜0.05）。结论: 原发EBV感染后随病程天数的增加,病毒复制水平逐渐下降。血浆中EBV游离DNA检测对评价EBV相关疾病的严重程度有一定参考价值。［中国当代儿科杂志,2009,11（11）：897-900］