应用基于Logistic回归的ROC曲线评价鼻咽癌EB病毒抗体联合检测

目的 以基于Logistic回归的受试者工作特征(ROC)曲线分析方法,评价VCA/IgA、EA/IgA、Rta/IgG和EBNA1/IgA等EB病毒抗体不同组合在鼻咽癌诊断中的价值.方法 收集211例初治鼻咽癌和203例相似症状的非鼻咽癌病例的血清,采用免疫酶法检测VCA/IgA及EA/IgA,酶联免疫吸附法检测Rta/lgG和EBNA1/IgA.对各种的抗体组合建立Logistic回归模型,以预测概率为分析指标,应用ROC曲线分析,评价不同组合对鼻咽癌的诊断价值.结果 单一指标评价,VCA/IgA敏感度最高(98.1%),EA/IgA特异度最高(98.5%).以基于Logistic同归的ROC曲线分析各项组合,敏感度和特异度均有所提高.双指标组合中,VCA/IgA+Rta/lgG组合的ROC曲线下面积(AUC)为0.991,诊断效能最高,敏感度、特异度及约登指数分别为94.8%、98.0%及0.928.VCA/IgA+Rta/IgG+EBNA1/IgA组合和4项指标组合的敏感度、特异度及约登指数分别为94.8%、98.5%、0.933和96.7%、97.0%、0.937;这两种多指标组合的AUC与VCA/IgA+Rta/IgG组合比较差异均无统计学意义(P＞0.05).结论 基于Logistic回归的ROC曲线分析方法可以为多指标联合诊断试验提供更客观的综合分析,VCA/IgA和Rta/IgG联合检测具有互补作用,是鼻咽癌血清学诊断的合适组合.     

血清EB病毒抗体水平与鼻咽癌患者预后的关系

目的 探讨血清EB病毒VCA/IgA、EA/IgA、NA1/IgA及Rta/IgG抗体水平与鼻咽癌患者预后的关系.方法 140例初治无远处转移的鼻咽癌患者分别在治疗前和治疗结束后采用免疫酶法检测血清VCA/IgA和EA/IgA,ELISA法检测NA1/IgA和Rta/IgG.随访进行远期疗效和生存的评价.结果 治疗后患者血清VCA/IgA、EA/IgA、NA1/IgA及Rta/IgG抗体水平较治疗前有明显下降,但仍显著高于正常对照组(P＜0.05).治疗后持续缓解的鼻咽癌患者其治疗前VCA/IgA、EA/IgA抗体水平显著低于疾病进展患者(P＜0.05).血清VCA/IgA、EA/IgA、NA1/IgA及Rta/IgG抗体水平与患者的3年总生存率无关(P＞0.05).治疗前VCA/IgA抗体高水平组(≥1∶320)及EA/IgA抗体高水平组(≥1∶80)患者的无进展生存期(61.8％,61.3％)低于抗体低水平组患者(86.5％,86.5％;P＜0.001).Cox回归分析显示治疗前VCA/IgA抗体水平是影响无进展生存的独立危险因素(HR=3.80,P=0.001).结论 VCA/IgA、EA/IgA可为鼻咽癌患者预后判断提供帮助.     

鼻咽癌EB病毒Rta/IgG抗体检测的诊断价值

目的 通过检测血清中的EB病毒Rta/IgG抗体,评价其在鼻咽癌诊断上的价值.方法 收集211例未经治疗的鼻咽癌患者,413例对照组(包括203例相似症状的非鼻咽癌病例和210例健康体检者)的血清,用酶联免疫吸附法(ELISA)检测Rta/IgG抗体.应用受试者工作特征(ROC)曲线对结果进行分析评价.结果 鼻咽癌组的Rta/IgG抗体rA值中位数明显高于对照组(P<0.001).Rta/IgG抗体检测诊断鼻咽癌的ROC曲线下面积为0.933,最佳截断点时敏感度为90.5%,特异度为90.1%.结论 采用ELISA方法检测血清中Rta/IgG抗体可以作为检测EB病毒的一个新指标,并可作为鼻咽癌诊断的重要标志物之一.     

五厂家EB病毒抗体检测试剂盒血清学诊断鼻咽癌的比较

目的 通过比较EB病毒抗体检测试剂盒血清学诊断鼻咽癌的准确性和检测结果的一致性,为试剂盒在临床上的使用选择和性能改进提供依据.方法 使用五厂家的EB病毒衣壳抗原IgA和IgG抗体检测试剂盒（VCA IgA和VCA IgG试剂盒）、核抗原I IgA和IgG抗体检测试剂盒（EBNA1 IgA和EBNA1IgG试剂盒）、早期抗原IgA和IgG抗体检测试剂盒（EA IgA和EA IgG试剂盒）以及Zta IgA抗体检测试剂盒,分别检测33例鼻咽癌患者（NPC）、30例健康体检者（HD）和41例非鼻咽癌的其他肿瘤患者（NNPC）血清或血浆样本.结果 A厂家的VCA IgA试剂盒灵敏度高于其他厂家同品种试剂盒,但对于NNPC特异度最低（36.6％）;而D厂家VCA IgA试剂盒的特异度最高（97.6％）,且对HD的特异度均大于90％.B和D厂家的EBNA1 IgA试剂盒间阳性、阴性符合率分别为92.1％和100.0％.A和E厂家的EA IgA试剂盒的灵敏度均较低而特异度高,试剂盒间阳性符合率低（39.4％）,阴性符合率高（98.6％）;而VCA IgG试剂盒的灵敏度高但特异度低.A和C厂家的EBNA1IgG试剂盒的灵敏度高（100.0％,97.0％）但特异度低（3.3％,13.3％）.C厂家EA IgG试剂盒检测所有样本结果均为阴性.结论 五个不同厂家VCA LgA、EA IgA试剂盒诊断鼻咽癌的准确性和检测结果的一致性存在差异,特别是A厂家和其他国内厂家同品种试剂间差异明显,需根据临床目的进行选择.三家国产VCA IgA试剂盒的灵敏度需进一步提高.相反,EBNA IgA试剂盒诊断鼻咽癌的准确性和结果一致性较好.单独使用VCA IgG和EBNA1 IgG试剂盒血清学诊断鼻咽癌的特异度差,其判读界值可能需根据检测且的进行调整.     

中山市健康成人外周血EB病毒抗体谱的调查研究

目的探讨来自不同地域的人群感染EB病毒的血清学抗体谱是否存在差异。方法从鼻咽癌高发区中山市的健康成人中收集348例中山籍贯原住居民的血清和81例外省籍贯居民的血清,用ELISA法检测血清中的EBNA1-IgA、EBNA1-IgG、VCA-p18-IgA、VCA-p18-IgG、Zta-IgA和Zta-IgG等6种抗体水平,比较不同抗体组合时两类人群样本的抗EB病毒抗体谱的差别。结果当三项IgA类抗体皆为阴性时,外省籍贯阴性率远远大于中山籍贯样本（P=0）;当EBNA1-IgA单阳时,外省籍贯样本阳性率远远高于中山籍贯样本（P=0.001）;当Zta-IgA单项阳性时（P=0.008）,或者Zta-IgA和VCA-p18-IgA同时阳性时（P=0.001）,中山籍贯样本阳性率明显高于外省籍贯样本;而三项IgG类抗体的任意组合,中山籍贯和外省籍贯都无统计学意义。结论中山籍贯原住居民感染的EB病毒常常处于激活状态;相反,外省籍贯的中山居民感染的EB病毒处于潜伏期时表达的EBNA1水平更高。提示中山籍贯原住居民比外省籍贯居民具有更高的风险罹患鼻咽癌。     

EBNA1-IgG抗体阳性患者免疫功能与肝功能损害的关系分析

目的:探究EBNA1-IgG抗体阳性患者免疫功能变化与肝功能损害的关系.方法:选取 2020 年 4 月至 2023年 4 月于我院就诊的78例EBNA1-IgG抗体阳性患者为研究对象.根据肝功能是否受损分为肝功能正常患者为观察组(44 例)和肝功能异常患者为对照组(34 例).比较两组患者空腹血清免疫球蛋白(IgM、IgG和IgA)水平和白细胞计数(White Blood Cell Count,WBC)、淋巴细胞计数(Lymphocyte count,Lym)、中性粒细胞计数(Neutrophil count,NEUT).采用Pearson相关性分析EBNA1-IgG抗体阳性患者免疫功能变化与肝功能损害的相关性.分析EBNA1-IgG抗体阳性患者肝功能损害的危险因素.结果:观察组IgM、IgG、IgA均低于对照组,其中IgG和IgA差异具有统计学意义(P＜0.05),IgM差异无统计学意义(P＞0.05).观察组WBC、Lym和NEUT指标低于对照组,差异具有统计学意义(P＜0.05).Pearson相关分析结果显示,EBNA1-IgG抗体阳性患者肝损伤与IgG、IgA、WBC、Lym和NEUT呈正相关.Logistic回归分析显示,Lym(OR=1.612,95%CI:1.056～2.459)为EBNA1-IgG抗体阳性患者合并肝功能损伤的独立危险因素.结论:EBNA1-IgG抗体阳性患者免疫功能变化与肝功能损害密切相关.     

EB病毒感染在风湿病中的意义

测定各种风湿病317例、鼻咽癌19例和正常人119例血清中的EB病毒(EBV)核抗原(EBNA)、壳抗原(EBVCA)和类风湿性关节炎相关核抗原(RANA)抗体,发现EBNA、EBVCA抗体检出率在各疾病组和正常人中无明显差异.但二者的平均滴度和高滴度血清阳性率在各疾病组显著高于正常人。RANA抗体检出率、平均滴度和高滴度血清阳性率在类风湿性关节炎(RA)患者较其它风湿病和正常人显著增高。提示多种风湿病对EBV均有异常的免疫应答反应,RANA及其所代表的EBV株在RA发病中可能有一定作用.     

RANA和EBNA抗体检测在类风关等疾病中的应用

<正>类风湿性关节炎相关核抗原（RANA）是一种受EB病毒诱导存在于淋巴细胞内的核抗原。许多研究证明类风湿性关节炎（RA）患者血清中有高滴度RANA抗体。RANA与EB病毒抗原特别是EB病毒核抗原（EBNA）有密切关系。Catalano等报告,RANA抗体与EBNA抗体滴度变化有关。本文用免疫荧光技术（IIF）检测RA及其他疾病中RANA抗体和EBNA抗体,并探讨其临床意义。1材料和方法1.1对象 RA患者68例,男12例,女56例。其他结缔组织病70例,包括干燥综合征（SS）7例;系统性红斑狼疮（SLE）24例;强直性脊椎炎（AS）20例;骨关节炎（OA）15例;硬皮病（PSS）4例。鼻咽癌（NPC）18例。正常人 51例。收集血清-30℃保存待测。1.2 RANA抗体检和使用IIF法。Raji细胞涂片。RANA抗体阳性可见大多数细胞核及胞浆内出现分布均匀的密集的细小颗粒型荧光。阳性参考血清由301医院栗占国赠送。1.3 EBNA抗体的检测 参照 Catalano方法,应用抗补体间接免疫荧光法。EBNA抗体阳性可见大多数细胞核出现均匀的荧光。1.4 阳性标准RANA 抗体和EBNA抗体均以≥1:10为阳性。阳性血清滴度取对数,并计算平均滴度。1.5统计学方法 所有资料均经方差分析或多元逐步回归,计算相关性及显著性。2结果2.1各组疾病及正常人RANA抗体和EBNA抗体阳性率结果见表1。     

EB病毒抗体与DNA载量联合检测在儿童传染性单核细胞增多症中的诊断价值

目的 探讨EB病毒IgG、IgA和IgM抗体及DNA载量联合检测在儿童传染性单核细胞增多症中的诊断价值.方法 收集2012年1月至2015年3月间我院收治的170例儿童传染性单核细胞增多症患者作为观察组进行回顾性分析,另取130例健康体检儿童作为对照组,对其EB病毒抗体检测情况和DNA载量检测情况进行观察对比.结果 观察组患者EB-DNA阳性率及载量,VCA-IgG及VCA-IgM阳性率均明显高于对照组,差异有统计学意义(P＜0.05);两组儿童VCA-IgA阳性率比较差异无统计学意义(P＞0.05).3～6岁患儿人数最多,达到全部患儿的49.41％,且随年龄增长,EB-DNA阳性率及载量、VCA-IgG阳性率均有明显增高趋势,差异有统计学意义(P＜0.05),而VCA-IgA及VCA-IgM则无明显差异(P＞0.05).各单项检测中,VCA-IgM具有最佳的诊断价值,与其他指标相比差异有统计学意义(P＜0.05).采用VCA-IgM联合EB-DNA检测可有效提高灵敏度、特异度、准确度、阳性预测值及阴性预测值等各项指标,差异有统计学意义(P＜0.05).结论 EB病毒VCA-IgG、VCA-IgA和VCA-IgM三种抗体在对儿童传染性单核细胞增多症的诊断中,以IgM具有最佳的敏感度、特异度及阳性预测值,采用VCA-IgM联合EB病毒DNA载量检测对于儿童传染性单核细胞增多症有良好的诊断价值,值得临床推广应用.     

广州地区EB病毒相关胃癌的临床病理特征及相关分子表达

目的 观察鼻咽癌高发区广州地区EB病毒相关胃癌的构成比、临床病理特征、EB病毒的潜伏类型,并初步探讨DNMT1、p16和cyclin D1在发病过程中的作用.方法 对676例胃癌采用组织芯片和EBER1原位杂交的方法筛选EB病毒相关胃癌,并用免疫组织化学EnVision法检测EB病毒潜伏期膜蛋白(LMP)和DNMT1、p16和cyclin D1的表达.结果 在676例胃癌中,45例EB病毒阳性(6.7%),EB病毒相关胃癌以男性为主,主要发生在胃的中上2/3,以弥漫型多见(P＜0.05).EBNA1和LMP2A的阳性例数分别为42例(93.3%)和24例(53.3%),EBNA2、LMP1和ZEBRA均未见表达.DNMT1、p16和cyclin D1在45例EB病毒相关胃癌的阳性例数分别为35例(77.8%)、10例(22.2%)和29例(64.4%),在40例EB病毒阴性胃癌的阳性例数分别为20例(50.0%)、25例(62.5%)和12例(30.0%),3个分子在两组胃癌的表达率差异均具有统计学意义(P＜0.05).p16与肿瘤的浸润深度有关(P＜0.05).LMP2A与DNMT1、DNMT1与p16、p16与cyclin D1存在相关关系(P＜0.05).结论 广州地区EB病毒相关胃癌占胃癌构成比的6.7%(45/676),EB病毒的潜伏类型部分为Ⅰ型,部分介于Ⅰ型和Ⅱ型之间.LMP2A、DNMT1、p16和cyclin D1的相互作用在EB病毒相关胃癌发生过程中起着重要的作用.     

Single-assay combination of Epstein-Barr Virus (EBV) EBNA1- and viral capsid antigen-p18-derived synthetic peptides for measuring anti-EBV immunoglobulin G (IgG) and IgA antibody levels in sera from nasopharyngeal carcinoma patients: options for field screening

Assessment of immunoglobulin A (IgA) antibody responses to various Epstein-Barr virus (EBV) antigen complexes, usually involving multiple serological assays, is important for the early diagnosis of nasopharyngeal carcinoma (NPC). Through combination of two synthetic peptides representing immunodominant epitopes of EBNA1 and viral capsid antigen (VCA)-p18 we developed a one-step sandwich enzyme-linked immunosorbent assay (ELISA) for the specific detection of EBV reactive IgG and IgA antibodies in NPC patients (EBV IgG/IgA ELISA). Sera were obtained from healthy donors (n = 367), non-NPC head and neck cancer patients (n = 43), and biopsy-proven NPC patients (n = 296) of Indonesian and Chinese origin. Higher values of optical density at 450 nm for EBV IgG were observed in NPC patients compared to the healthy EBV carriers, but the large overlap limits its use for NPC diagnosis. Using either EBNA1 or VCA-p18 peptides alone IgA ELISA correctly identified 88.5% and 79.8% of Indonesian NPC patients, with specificities of 80.1% and 70.9%, whereas combined single-well coating with both peptides yielded sensitivity and specificity values of 90.1 and 85.4%, respectively. The positive and negative predictive values (PPV and NPV, respectively) for the combined EBNA1 plus VCA EBV IgA ELISA were 78.7% and 93.9%, respectively. In the Indonesia panel, the level of EBV IgA reactivity was not associated with NPC tumor size, lymph node involvement, and metastasis stage, sex, and age group. In the China panel the sensitivity/specificity values were 86.2/92.0% (EBNA1 IgA) and 84.1/90.3% (VCA-p18 IgA) for single-peptide assays and 95.1/90.6% for the combined VCA plus EBNA1 IgA ELISA, with a PPV and an NPV for the combined EBV IgA ELISA of 95.6 and 89.3%, respectively. Virtually all NPC patients had abnormal anti-EBV IgG diversity patterns as determined by immunoblot analysis. On the other hand, healthy EBV carriers with positive EBV IgA ELISA result showed normal IgG diversity patterns. By using EBV IgG immunoblot diversity as confirmation assay for EBV IgA ELISA-positive samples, the sensitivity and specificity for NPC diagnosis increased to 98% and 99.2%, respectively, in the Indonesian NPC samples. The use of these combined methods for seroepidemiological screening studies is proposed.     

两阶段EB病毒酶联免疫吸附法筛查鼻咽癌的探讨

目的：采用两阶段EB病毒血清学筛查方法，进行人群鼻咽癌的筛查。方法：用ELISA检测血清EB病毒抗体，首先以EBNAlIgA作为人群鼻咽癌的初筛指标，第二阶段的检查是在EBNAlIgA阳性人群中再进一步检测EBNAlIgG和ZtaIgG两种抗体。结果：EBNAlIgA的灵敏度和特异度分别为91．9％和91．4％，均高于EBNAlIgG和ZtaIgG；第二阶段检查可以将鼻咽癌筛查的特异度提高到96．5％，同时可将人群划分高、中、低三个不同危险层次，其中高危险人群仅占0．39％。结论：实行两阶段筛查法，使鼻咽癌筛查既能达到良好的灵敏度，又能提高检测的特异性，同时还可以将筛查人群划分不同的危险层次。     

Diagnostic value of measuring Epstein-Barr virus (EBV) DNA load and carcinoma-specific viral mRNA in relation to anti-EBV immunoglobulin A (IgA) and IgG antibody levels in blood of nasopharyngeal carcinoma patients from Indonesia

Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in Southeast Asia and is strongly associated with Epstein-Barr virus (EBV). We investigated the primary diagnostic value of circulating EBV DNA and anti-EBV immunoglobulin G (IgG) and IgA levels in Indonesian NPC patients (n = 149). By a 213-bp Epstein-Barr virus nuclear antigen 1 (EBNA1)-based real-time LightCycler PCR, 72.5% of patients were positive for EBV DNA in whole blood, with 29.5% having levels above a previously determined clinical cutoff value (COV) of 2,000 EBV DNA copies/ml, the upper level in healthy carriers. In a 99-bp LightCycler PCR, 85.9% of patients were positive and 60.4% had levels above the COV. This assay quantified a significantly higher EBV load than the 213-bp PCR assay (P < 0.0001), suggesting that circulating EBV DNA is fragmented. Using data from 11 different studies, we showed a significant inverse correlation between PCR amplicon size and the percentage of patients positive for circulating EBV DNA (Spearman's rho = -0.91; P < 0.0001). EBV DNA loads were unrelated to anti-EBV IgG or IgA levels, as measured by VCA-p18 and EBNA1-specific synthetic peptide-based enzyme-linked immunosorbent assays. The presence of circulating tumor cells was assessed by amplification of BamHI-A rightward frame 1 (BARF1) mRNA, a viral oncogene abundantly expressed in EBV-carrying carcinomas but virtually absent from EBV-associated lymphomas. Despite high EBV DNA loads and the presence of EBNA1 and human U1A small nuclear ribonucleoprotein mRNA, BARF1 mRNA was never detected in blood. We conclude that amplicon size significantly influences EBV DNA load measurement in NPC patients. The circulating EBV DNA load is independent of serological parameters and does not reflect intact tumor cells. The primary diagnostic value of the EBV DNA load for the detection of NPC is limited.     

Significance of specific Epstein-Barr virus IgA and elevated IgG antibodies to viral capsid antigens in nasopharyngeal carcinoma patients

The feasibility of using elevated Epstein-Barr virus (EBV) specific-IgG antiviral capsid antigen (VCA) and IgA anti-VCA antibody levels as an aid in diagnosis of nasopharyngeal carcinoma (NPC) was analyzed by determination of serum antibody titers to EBV in 54 NPC patients, 114 healthy blood donors, and 40 family members by the immunoperoxidase assay (IPA). No significant difference was found in the prevalence rate of EBV IgG anti-VCA antibodies (titer greater than or equal to 20) between the patient group and the control and family groups (100% vs 92% and 90%, respectively). The prevalence rate of elevated EBV IgG anti-VCA titers (greater than or equal to 80, greater than or equal to 160, greater than or equal to 320, greater than or equal to 640) was significantly higher in the NPC patients than in controls. For example, at an IgG titer of greater than or equal to 320, the prevalence rate was 82% in the NPC patient group and 1.7% in the controls (P less than 0.0001). The prevalence of EBV IgA anti-VCA antibodies (greater than or equal to 10) was significantly higher in the NPC patients than in control and family groups (82% vs 6.1% and 0%, respectively). The prevalence rate for elevated EBV IgA anti-VCA (greater than or equal to 20) was found to be significantly higher (P less than 0.0001) in NPC patients than in the control group (70% vs. 1.7%). A significantly high proportion (P = 0.0004) of NPC patients who had serum EBV IgA anti-VCA titers of less than 20 had elevated IgG titers to VCA greater than or equal to 320 (21% vs 1.7% among controls). It appears that testing for IgG antibodies at a serum dilution of 1:320 and for IgA antibodies at a dilution of 1:20 by the IPA technique comprises the best combination for the differentiation between NPC patients and health controls (91% vs 3.4%), and it is suggested that these be used as screening markers for NPC patients.     

Evaluation of commercial EBV RecombLine assay for diagnosis of nasopharyngeal carcinoma

BACKGROUND: In recent years a number of Epstein-Barr virus (EBV) proteins were defined as being immunodominant for either IgM, IgG or IgA immune responses, yielding promising markers for diagnostic serology. Specific reactivity patterns to these proteins have been described for infectious mononucleosis (IM), nasopharyngeal carcinoma (NPC), various types of lymphoma, and healthy EBV carriers. OBJECTIVES: To compare the NPC-related diagnostic value of EBV RecombLine test (Mikrogen, Germany) with a standardized immunoblot assay [Fachiroh J, Schouten T, Hariwiyanto B, Paramita DK, Harijadi A, Haryana SM, et al. Molecular diversity of Epstein-Barr virus IgG and IgA antibody responses in nasopharyngeal carcinoma: a comparison of Indonesian, Chinese, and European subjects. J Infect Dis 2004;190:53-62] and to define the diagnostic value of individual EBV marker proteins in a population with high incidence of NPC. RESULT: Sera from Indonesian NPC patients taken at primary diagnosis (n=108) were analyzed for IgG and IgA reactivity and compared with regional healthy blood donors (n=62), non-NPC patient controls (n=10) and IM patients (n=10). Most NPC patients and controls showed strong IgG reactivity to VCA-p18, -p23, and EBNA1, limiting their diagnostic use. Few (<20%) healthy donors and patient controls showed IgG reactivity to EA proteins p47/54 and p138, yielding combined sensitivity/specificity and PPV/NPV values of 92.6%/98.3% and 99.0%/88.1%, for diagnosing NPC. NPC sera showed significantly more EBV reactive IgA antibody (>80% positive) than controls (<10% positive), although being less broadly reactive and significantly less strong compared to IgG. For IgA best results were observed for RecombLine EBNA1 with sensitivity/specificity and PPV/NPV values of 92%/89% and 93.4%/85.9%, respectively. CONCLUSION: In high incidence NPC regions with low incidence IM yet high prevalence of EBV infection, both RecombLine IgG and IgA tests provide a useful alternative to the more complex cell-extract based immunoblot assay as confirmation test for NPC diagnosis in particular when using EA and EBNA1 as discriminators in IgG and IgA testing, respectively.     

Humoral immune responses to Epstein-Barr virus encoded tumor associated proteins and their putative extracellular domains in nasopharyngeal carcinoma patients and regional controls

Epstein-Barr virus (EBV) latency proteins EBNA1, LMP1, LMP2, and BARF1 are expressed in tumor cells of nasopharyngeal carcinoma (NPC). IgG and IgA antibody responses to these non-self tumor antigens were analyzed in NPC patients (n=125) and regional controls (n=100) by three approaches, focusing on the putative LMP1, LMP2 extracellular domains. Despite abundant IgG and IgA antibody responses to lytic antigens and EBNA1, patients had low titer (1:25-1:100) IgG to LMP1 (81.2%), LMP2 (95.6%), and BARF1 (84.8%), while immunoblot showed such reactivity in 24.2%, 12.5%, and 12.5% at 1:50 dilution, respectively. Few IgA responses were detected, except for EBNA1. Controls only showed IgG to EBNA1. ELISA using peptides from different domains of LMP1, LMP2, and BARF1 also yielded mostly negative results. When existing, low level IgG to intracellular C-terminus of LMP1 (62.9%) prevailed. Rabbit immunization with peptides representing extracellular (loop) domains yielded loop-specific antibodies serving as positive control. Importantly, these rabbit antibodies stained specifically extracellular domains of LMP1 and LMP2 on viable cells and mediated complement-driven cytolysis. Rabbit anti-LMP1 loop-1 and -3 killed 50.4% and 59.4% of X50/7 and 35.0% and 35.9% of RAJI cells, respectively, and 22% of both lines were lysed by anti-LMP2 loop-2 or -5 antibodies. This demonstrates that (extracellular domains of) EBV-encoded tumor antigens are marginally immunogenic for humoral immune responses. However, peptide-specific immunization may generate such antibodies, which can mediate cell killing via complement activation. This opens options for peptide-based tumor vaccination in patients carrying EBV latency type II tumors such as NPC.