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-连锁淋巴组织增殖综合征的临床表型和诊断

X-连锁淋巴组织增殖综合征(XLP)是一种少见的、常常是致死性的原发性免疫缺陷病,可由EB病毒感染诱发,表现为爆发性传染性单核细胞增多症、丙种球蛋白异常血症和淋巴增殖性疾病以及淋巴瘤.本病主要由编码淋巴信号活化分子相关蛋白(SAP)、X-连锁凋亡抑制因子(XIAP)和IL-2诱导的T细胞激酶(ITK)基因的突变引起.基因序列分析是确诊XLP的依据;SAP、XIAP、ITK蛋白的表达也可以作为筛查XLP的手段.家族史是需要考虑的主要客观指标,其他诊断标准包括患儿的临床表现、EB病毒感染后的EBNA抗体检测等.     

EB病毒检测与EB病毒感染诊断的研究

目的 探讨EB病毒(EBV)检测在EBV感染诊断中的临床意义.方法 应用酶联免疫吸附方法 和荧光定量PCR方法 同步检测38例疑诊EBV感染患儿入院时及起病1、3、6、9个月血浆中EBV VCR-IgM及外周血全血、血浆、单个核细胞(PBMC)中EBV DNA,比较EBV感染患儿病程中4种检测方法 的检出率.结果 在疑诊EBV感染初期,全血和PBMC中EBV DNA阳性率最高,与EBV VCR-IgM及血浆EBV DNA相比,差异具有显著性(P<0.05);起病后的1、3、6及9个月,4种检出方法 的阳性率均逐渐减低,但PBMC中EBV DNA敏感性始终高于其他3种方法 .结论 EBV感染初期,检测全血和PBMC中EBV DNA是早期、快速、敏感的检测方法 ;EBV可长期存在于PBMC中,荧光定量PCR法检测外周血PBMC中EBV DNA对EBV感染的诊断有重要价值,可作为判断疗效及监测病情的一种有效手段.     

荧光定量PCR检测传染性单核细胞增多症EB病毒的评价

目的 研究荧光定量PCR检测传染性单核细胞增多症(以下简称传单)EB病毒(EBV)DNA量的意义,了解EBV DNA拷贝量与病情程度的相关性.方法 采用荧光定量PCR检测2004年6月至2006年6月在湖南省人民医院儿科住院的68例传单患儿外周血单个核细胞(PBMCs)EBV DNA量,根据病情将患儿分为单器官系统组和多器官系统组,比较两组EBV DNA量.结果 (1)传单患儿EBV DNA阳性率为86.8%,拷贝量均值为13200拷贝/mL.(2)EBV DNA量在单器官系统组和多系统组差异有统计学意义(P＜0.05).传单患儿器官损害越多,EBV DNA拷贝量越高.结论 PBMCs荧光定量PCR检测EBV DNA量是有助传单诊断、治疗的较好手段.监测EBV DNA量对及早评估病情、及早治疗有一定指导意叉.     

原发性免疫缺陷病合并卡介苗感染新型白介素12受体β1基因突变一例

目的 分析一例白介素12受体β1(IL-12Rβ1)缺陷基因突变合并卡介苗感染患儿的临床特征、基因分析和蛋白表达.方法 根据典型的临床表现及免疫学筛查实验排除常见原发性免疫缺陷病(PID),用单克隆抗体流式细胞术检测患者和母亲EB病毒(EBV)永生化的B细胞上IL-12Rβ1蛋白表达,同时,用正向、反向引物分别对患儿和其父、母的IL-12Rβ1基因进行PCR扩增并测序,患儿弟弟产前、产后均已作IL-12Rβ1基因分析.结果 患儿有严重、播散性卡介苗接种病,其永生化的B细胞上IL-12Rβ1蛋白表达呈阴性,母亲有部分蛋白表达.患儿为IL-12Rβ1基因纯合单核苷酸替换突变,其第9外显子853位核苷酸(C→T)发生无义突变,使第285位谷氨酸突变为终止密码(Q285X),其父、母亲均为该异常基因的携带者,患儿弟弟产前产后IL-12Rβ1基因正常.结论 鉴定出一例新型IL-12Rβ1基因突变(Q285X)患者,发现此基因突变患者的IL-12Rβ1蛋白缺乏,确定此基因突变是引起患者发生播散性卡介苗接种病的根本原因;明确家庭成员携带情况,为产前诊断提供依据.     

X连锁淋巴组织增殖性疾病研究进展

X连锁淋巴组织增殖性疾病(X-linked lymphoproliferative disease,XLP)是一种性连锁隐性联合免疫缺陷性疾病,其特征为对Epstein-Barr病毒(EBV)感染不能产生有效的免疫应答,与免疫功能正常人群EBV感染后发生短暂的自限性淋巴细胞增殖反应不同,XLP男性患儿往往出现失控性的淋巴组织和细胞增生。XLP相关致病基因SH2D1A已克隆,     

SH2D1A基因突变的淋巴瘤患儿6例病例系列报告

背景：SH2D1A 基因突变的儿童淋巴瘤临床罕见且有其特殊的临床特征及疾病预后。 目的：总结伴SH2D1A基因突变的儿童淋巴瘤临床表现、病理特点、治疗方案和预后。 设计：病例系列报告。 方法：纳入2017年6月至 2022年7月于首都医科大学附属儿童医院（我院）初诊为淋巴瘤且年龄＜18岁,经高通量全外显子基因测序提示SH2D1A 基因突变的连续住院病例。根据病理诊断确定治疗方案：侵袭性成熟B细胞淋巴瘤基于改良的LMB89方案治疗;成熟T细胞淋巴瘤合并家族性噬血细胞综合征（HLH）患儿先以HLH方案控制病情,确诊后予SMILE方案化疗。化疗2~3个月行中期疗效评估。化疗结束后3个月评估超声和PET/CT,化疗结束第1、2年内每3个月评估瘤灶超声、肝功能、LDH和免疫功能。 主要结局指标：SH2D1A基因突变淋巴瘤患儿的临床特征和预后。 结果6例伴SH2D1A基因突变淋巴瘤患儿,均为男性;中位发病年龄5（4~12）岁。瘤灶累及胃肠道3例,中枢神经系统、头颈部和多脏器浸润各1例;临床分期：Ⅱ期1例,Ⅲ期3例,Ⅳ期2例;病理类型：3例弥漫大B细胞淋巴瘤,1例高级别成熟B细胞淋巴瘤,1例伴11q异常的伯基特样淋巴瘤,1例儿童系统性EB病毒阳性T细胞淋巴瘤。5例患儿体液免疫和/或细胞免疫指标下降。5例病初全血和血浆EBV DNA均阴性,其中2例病程中复测全血EBV DNA上升至≥105拷贝数/mL;1例病初合并HLH,多次全血EBV DNA为106拷贝数/mL。6例均提示SH2D1A基因突变,2例完善SAP蛋白检测未见异常;1例染色体异常。3例完成化疗,2例因HLH死亡,1例予利妥昔单抗免疫治疗。 结论：SH2D1A基因突变的淋巴瘤患儿临床少见,病理形态多表现为非霍奇金淋巴瘤（成熟B细胞淋巴瘤）,预后较差,在合适时机考虑行异基因造血干细胞移植可改善疾病预后。     

X连锁淋巴组织增殖性疾病发病机制研究进展

X连锁淋巴组织增殖性疾病(XLP)是一种先天性免疫缺陷病,主要表现为对EB病毒极其易感,导致致死性感染性单核细胞增多症、血中丙种球蛋白异常和恶性淋巴瘤。随着分子生物学、遗传学的发展,XLP基因(SH2D1A)已被定点克隆,其编码产物SAP在通过SLAM介导的信号传导方面,针对FynT(一种酪氨酸激酶)发挥衔接子功能,针对SHP-2(一种磷酸酶)的连接则起阻止剂作用。EB病毒可能是引起XLP发病的潜在触发点,而血细胞上SAP表达缺陷则与XLP发病与否有关。     

X连锁淋巴组织增殖性疾病发病机制研究进展

X连锁淋巴组织增殖性疾病(XLP)是一种先天性免疫缺陷病，主要表现为对EB病毒极其易感，导致致死性感染性单核细胞增多症、血中丙种球蛋白异常和恶性淋巴瘤。随着分子生物学、遗传学的发展，XLP基因(SH2D1A)已被定点克隆，其编码产物SAP在通过SLAM介导的信号传导方面，针对FynT(一种酪氨酸激酶)发挥衔接子功能，针对SHP-2(一种磷酸酶)的连接则起阻止剂作用。EB病毒可能是引起XLP发病的潜在触发点，而血细胞上SAP表达缺陷则与XLP发病与否有关。     

巨脑性白质脑病伴皮层下囊肿一家系MLC1基因突变分析

目的通过对巨脑性白质脑病伴皮层下囊肿(MLC)一家系的分析,确定其MLC1基因的改变及遗传特征。方法收集先证者及其家系成员的临床资料,采用聚合酶链反应(PCR)和DNA直接测序方法进行MLC1基因突变检测,确定基因突变位点,明确MLC诊断。结果本家系先证者临床符合MLC诊断。测序结果发现两个基因位点改变c.218G>A(p.Gly73Glu)和IVS9-1G>C。患儿为复合杂合突变致病,其c.218G>A突变来自母亲,IVS9-1G>C突变来自父亲,其父母均为表型正常携带者。结论此家系中1例中国MLC患儿存在MLC1基因复合杂合突变,一个是错义突变,另一个是剪接位点突变。     

Simultaneous manifestation of fulminant infectious mononucleosis with haemophagocytic syndrome and B-cell lymphoma in X-linked lymphoproliferative disease

X-linked lymphoproliferative disease is a rare T and NK cell immune deficiency which most frequently presents as fulminant infectious mononucleosis following infection with the Epstein-Barr virus (EBV). We report the case of a 4-year-old boy from a Spanish family presenting with severe infectious mononucleosis. In the course of the disease he developed hepatic failure, pancytopenia and neurologic impairment, leading to death after less than 2 months. The results of bone marrow biopsy and autopsy indicated a histological diagnosis of both high-grade B-cell lymphoma and virus-associated haemophagocytic syndrome, thereby confirming the simultaneous presence of two different manifestations of X-linked lymphoproliferative disease (XLP) in this patient. The family history revealed four close male relatives dying under similar circumstances, one of whom died following a vaccination against measles. Molecular genetic studies identified a novel mutation in the SH2D1A gene in several members of the family, establishing the diagnosis of XLP. Fatal EBV infection in male infants is highly indicative of XLP. Virus-associated haemophagocytic syndrome and B-cell lymphoma can occur concomitantly and may be difficult to distinguish due to their similar histological pictures.     

X-Linked Lymphoproliferative Disease: Pathology and Diagnosis

X-linked lymphoproliferative disease (XLP) is a rare familial disorder resulting in selective immunodeficiency to the Epstein-Barr virus (EBV), characterized by uncontrolled proliferation of EBV-infected lymphocytes. Phenotypes of this disease are variable and include fulminant infectious mononucleosis, hypogammaglobulinemia, and malignant lymphoma. In this article, we describe a case of a previously healthy 4-year-old boy with serologic evidence of acute EBV infection who died of fulminant hepatic failure. Histopathological examination of tissue obtained postmortem showed hemophagocytosis and prominent polymorphous infiltrates associated with necrosis in the liver, spleen, and lymph nodes. Semiquantitative polymerase chain reaction (PCR) utilizing primers complementary to the EBV gene LMP2a performed on samples of liver tissue demonstrated approximately 0.6 copies of the EBV gene per cell. Immunohistochemistry demonstrated light chain restriction and PCR studies of the immunoglobulin V-D-J region revealed two strong bands, consistent with a clonal B cell proliferation. Extended family history revealed that the boy's family was followed by the XLP Registry, which was established in 1978 to follow kindreds with XLP. The genetic abnormality associated with XLP has been localized to the Xq25, allowing RFLP analysis to identify female carriers and affected boys.     

Lymphocytic vasculitis involving the central nervous system occurs in patients with X‐linked lymphoproliferative disease in the absence of Epstein–Barr virus infection

X‐linked lymphoproliferative disease (XLP) is an immunodeficiency caused by defects in the adaptor molecule SAP. The manifestations of XLP generally occur following Epstein–Barr virus (EBV) infection and include fulminant mononucleosis, hypogammaglobulinemia and lymphoma. In this report, we describe two unrelated patients with fatal T‐cell‐mediated central nervous system vasculitis for whom repeated serologic and molecular testing for EBV was negative. In both patients, clonal T‐cell populations were observed, but neither demonstrated evidence of lymphoma. Thus, loss of SAP function can lead to dysregulated immune responses characterized by the uncontrolled expansion and activation of T cells independent of EBV infection. Pediatr Blood Cancer 2009;53:1120–1123. © 2009 Wiley‐Liss, Inc.     

Atypische Epstein-Barr-Virus(EBV)-Infektionen im Kindes- und Jugendalter

The clinical syndrome of acute infectious mononucleosis is predominantly a disease of older children and adolescents. Primary EBV infection in younger infants is often subclinical. Complications may affect any organ system and are usually mild. In the majority of cases acute infectious mononucleosis has an excellent prognosis. Severly immuncompromised children and adolescents (i. e. under immunosuppressive therapy, after stem cell transplantation) may develop EBV⁺ B-cell lymphoproliferative disorders and malignant B-cell lymphoma. In this review, mainly the following forms of atypical EBV infections are described in detail: Fulminant, mostly fatal acute infectious mononucleosis following primary EBV infection may occur 1) sporadically (approx. 1 per 3000 cases of acute infectious mononucleosis), 2) in aprox. 60% of boys with X-linked lymphoproliferative disease (XLP), and 3) in very rare cases of a fulminant EBV+ T-cell lymphoproliferative disorder. No efficient therapy exists so far. Early allogeneic stem cell transplantation in boys with XLP may prevent fatal acute infectious mononucleosis and other complications. Chronic active EBV (CAEBV) infection is characterized by recurrent clinical episodes of severe infectious mononucleosis over months or years and additional unusual clinical signs and complications such as coronary artery aneurisms, hypersensitivity to mosquito bites and hydroa vacciniforme, as well as an markedly increased risk for malignant lymphoma, mostly of a T-cell type. In general, prognosis of CAEBV infection is poor. Allogeneic stem cell transplantation may lead to clinical remission. EBV-associated hemophagocytic syndrome may occur as an independent disorder [EBV-related hemophagocytic lymphhistiocytosis (EBV-HLH)] or as a serious complication of fatal infectious mononucleosis or CAEBV infection. Early treatment with etoposide, cyclosporine A and corticosteroids may improve the otherwise poor prognosis. The pathogenesis of atypical EBV infections is not known in most cases. Further molecular and immunologic studies may help to characterize these severe disorders and to develop more specific and more efficient therapies.     

X linked lymphoproliferative disease in a United Kingdom family

X linked lymphoproliferative disease (XLP; Duncan's disease) is a rare disorder affecting boys and characterised by a defective immune response to Epstein-Barr virus caused by a mutation in a gene located at chromosome Xq25. Three siblings with XLP in a single UK family are reported and the variation in phenotypic expression of the disease in these siblings described. One of the siblings with life threatening fulminant infectious mononucleosis was successfully treated by chemotherapy, followed by bone marrow transplantation using an unaffected brother as the donor. A healthy baby boy recently born into the family was identified as carrying the defective maternal X chromosome using molecular genetic linkage analysis. This family illustrates the extent of present understanding of this often fatal condition.     

Malignant B-cell lymphoma following and associated with infectious mononucleosis. A comparison of two cases

The present report describes two young males with clinically diagnosed infectious mononucleosis (IM) who subsequently were diagnosed as having malignant B-cell lymphoma (i.e., immunoblastic sarcoma of B-cells). Despite these apparent similarities, there were fundamental differences between the two cases. The first patient, who lymphoma was diagnosed 9 months after IM, was one of a well-described kindred with the X-linked lymphoproliferative syndrome (XLP) in which affected young males lack the ability to mount an effective immune response to primary infection with the Epstein-Barr virus (EBV) (i.e., infectious mononucleosis), and subsequently develop fatal lymphoproliferative disorders of the B-cell type. This was in contrast to a second patient, also a young male, who did not have the X-linked lymphoproliferative syndrome, who did develop specific antibodies to the Epstein-Barr virus and whose malignant lymphoma was closely associated in time (i.e., 5 weeks) with the clinical diagnosis of infectious mononucleosis. The comparative immunologic and virologic features are discussed as well as the importance of careful clinicopathologic correlation in young adults and children developing malignant lymphoma both following and in association with infectious mononucleosis.     

HHV-8-related hemophagocytic lymphohistiocytosis in a boy with XLP phenotype

We report a 2.5-year-old boy with an X-linked lymphoproliferative disease (XLP) phenotype who presented with human herpes virus-8 (HHV-8)-related hemophagocytic lymphohistiocytosis (HLH). XLP is a rare primary immunodeficiency characterized by extreme susceptibility to herpes viruses, mainly Epstein-Barr virus (EBV). Approximately 60% of patients with XLP present with fulminant mononucleosis associated with HLH, whereas remaining patients present with hypogammaglobulinemia or lymphoproliferative disease. Most commonly, one of the XLP phenotypes appears after exposure to EBV, but at least 12% of affected individuals developed symptoms without an evidence of EBV infection. Rarely, patients with XLP may present with central nervous system vasculitis or aplastic anemia. HHV-8 is lymphotrophic and it is associated with lymphoproliferative disorders and Kaposi sarcoma in immunodeficient hosts. Kaposi sarcoma rarely occurs in children with well-defined primary immunodeficiency. Also, HHV-8-related HLH was previously reported in 2 siblings with a perforin gene deficiency. Recently, it became evident that besides EBV, other viruses may trigger the symptoms in XLP. We report for the first time HHV-8-related HLH in EBV-negative pediatric patient with an XLP phenotype.