EB病毒两种抗体联合检测在鼻咽癌诊断中的应用

目的探讨EB病毒（epstein—barr virus,EBV）抗体在鼻咽癌早期诊断中的应用价值。方法采用酶联免疫吸附试验（ELISA）测定53例鼻咽癌患者、71例鼻部疾病患者和40例正常体检人群血清EBV相关抗体（EBV VCA—IgA和EA—IgA）。结果3组比较,鼻咽癌组血清VCA—IgA的阳性检出率为79．2％,EA-IgA阳性率为50．9％,与其余两组比较差异有统计学意义（P〈0．01）;鼻咽癌组和鼻部疾病组内VCA-IgA和EA-IgA的阳性率比较差异有统计学意义（P〈0．01）;检测鼻咽癌组两项指标的吸光度均值较另两组高;VCA-IgA单独检测及两项联合检测均具有较高的敏感性（79．2％）,EA-IgA单独检测及两项联合检测均具有较强的特异性（93．8％）。结论联合检测鼻咽癌病人血清的VCA—IgA和EA—gA可兼具两者的性能优势,敏感性较高,特异性较强。对鼻咽癌的早期诊断具有重要的临床应用价值。     

EB病毒与人疱疹病毒6型感染在药疹发生中的作用

目的 本研究主要就人疱疹病毒6型(HHV-6)与EB病毒(EBV)感染在药疹产生过程中的作用展开分析,以此来为药疹患者的临床治疗提供参考.方法 选择我院2012年12月--2013年12月所收治的62例药疹患者作为观察组,另选148例健康献血人员作为对照组,采用巢式PCR对HHV6 DNA进行检测、采用PCR-Southern对EBV DNA进行检测、采用ELISA法对EBV VCA-IgM进行检测,并对其检测结果进行比较.结果 两组患者的EBV DNA、HHV6 DNA、EBV VCA-IgM阳性率存在明显差异,具有统计学意义(P＜0.05).结论 绝大部分药疹患者存在EBV感染的情况,且EBV感染与HHV6感染之间存在相互激活的作用,在药疹诊断过程中具有较高的临床应用价值,可以将其作为药疹的临床诊断指标之一.     

宁夏某医院患者TB DNA检测分析

目的 探讨宁夏某医院TB DNA感染现状及临床特点。方法 对我院就诊的疑似结核病感染患者1828例进行回顾分析,用实时荧光定量PCR检测血浆TB DNA。结果 TB DNA阳性患者32例,总阳性率为1.75%,男、女性阳性率分别为2.17%和1.17%,差异无统计学意义（P＞0.05）。童年组（0~6岁）阳性率最高为2.86%,与其他年龄组相比,差异无统计学意义（P＞0.05）。春季（3~5月份）TB DNA阳性率最高为3.21%,与其他季节相比,差异有统计学意义（P＜0.05）。2015年~2017年TB DNA阳性率有逐年下降趋势（2.06%、2.00%、1.16%）。TB DNA阳性患者就诊临床科室主要以泌尿外科（6.11%）、呼吸内科（5.26%）、肝胆外科（4.35%）为主。结论 TB DNA检测有助于结核病的早期诊断,为临床防治结核病提供重要依据。     

EB病毒、巨细胞病毒、单纯疱疹病毒和柯萨奇病毒感染和多发性硬化复发关系的研究

目的 探讨0EB病毒(EBV)、巨细胞病毒(CMV)、单纯疱疹病毒-1(HSV-1)、柯萨奇病毒B组Ⅰ-Ⅵ型近期活动性感染和复发.缓解型多发件硬化(RR MS)复发的关系.方法 采用酶联免疫吸附法检测34例RR MS患者和200名正常对照者血浆EB病毒、巨细胞病毒、单纯疱疹病毒-1、柯萨奇病毒B组Ⅰ-Ⅵ型IgM抗体,比较病例组和对照组间上述病毒近期活动性感染率的差别,并对病例组病毒近期活动性感染者和无活动性感染者的临床资料进行分析比较.结果 两组问EB病毒、巨细胞病毒、单纯疱疹病毒-1及柯萨奇病毒B组Ⅰ、Ⅱ、Ⅲ、Ⅵ型IgM抗体阳性率的差异无统计学意义.RR MS组和对照组间柯萨奇病毒B组Ⅳ型、Ⅴ型IgM抗体阳性的差异有统计学意义(分别为3/34和0/200,P<0.05;2/34和0/200,P<0.05).病例组中任一病毒近期活动性感染者和无活动性感染者相比,其年龄、病程、发作次数、入院体温、血白细胞分类计数(中性粒细胞、淋巴细胞和单核细胞)、糖皮质激素应用与否及EDSS分值间的差异均无统计学意义.结论 RR MS患者复发期柯萨奇病毒B组Ⅳ型、Ⅴ型近期活动性感染率较高,但近期病毒活动性感染和症状的严重度无关,未发现EBV、CMV、HSV与RR MS复发的关系.     

非霍奇金淋巴瘤EB病毒特异DNA序列的检测

目的　探讨EB病毒 (EBV)与中国南方地区非霍奇金淋巴瘤 (NHL)的相关性 ,以及EBV与不同类型NHL的关系。方法　采用PCR技术 ,检测 2 0 6例石蜡包埋的NHL组织及 2 3例反应性增生的淋巴组织中的EBV特异DNA序列。结果　(1 ) 2 0 6例NHL组织中 ,94例PCR扩增出EBV特异的DNA序列 ,阳性率 4 5 6 % ;对照组反应性增生的淋巴组织 2 3例中 ,5例阳性 ,阳性率 2 1 7% ;两者差异有显著性 (P <0 0 5 )。 (2 ) 2 0 6例NHL中B NHL 1 2 8例 ,EBV阳性者 4 8例 ,阳性率 37 5 % ;T NHL 78例 ,EBV阳性者 4 6例 ,阳性率 5 9 0 %。两者差异有显著性 (P <0 0 5 )。结论　EBV与中国南方地区NHL ,特别是T NHL有一定的相关性     

联合检测血清唾液酸和EBVCA-IgA对鼻咽癌诊断及疗效监测的意义

目的 探讨联合检测血清唾液酸（SA）和EB病毒壳抗原IgA抗体（EBVCA-IgA）在鼻咽癌（NPC）患者诊断及疗效监测中的意义.方法 对65例NPC患者治疗前、治疗结束后1个月、和21例治疗后1年出现局部复发或远处转移者,50例头颈部良性病变患者及50例正常人血清SA与EBVCA-IgA进行联合检测.结果 NPC患者治疗前血清SA和EBVCA-IgA阳性率均明显高于正常人和头颈部良性病变患者,差异有统计学意义（均P＜0.01）;联合检测敏感性达到96.9%,明显高于SA、EBVCA-IgA的单项检测（P＜0.05）,同时特异性仍有91.0%.与NPC治疗前组比较,NPC治疗后组和未复发组的血清SA水平明显下降（P＜0.01）,NPC治疗后复发组较未复发组患者的血清SA水平明显上升（P＜0.01）,而EBVCA-IgA的阳性率的变化却不明显.结论 血清SA水平可作为判断NPC疗效及监测病情的一种有效手段,联合检测血清SA水平和EBVCA-IgA阳性率,可明显提高NPC患者的阳性检出率.     

乳腺癌患者血浆循环DNA含量分析及其临床意义

目的:检测乳腺癌患者血浆循环DNA含量, 探讨其与临床病理特征之间的关系.方法:收集80例乳腺癌、 40例乳腺良性病变患者和97例健康自愿者的外周血.用微量基因组DNA 提取试剂盒提取血浆DNA, 用荧光染料试剂盒和QubitTM荧光仪测定血浆DNA含量.结果:(1)血浆循环DNA含量在组织学分级Ⅰ级和Ⅱ～Ⅲ级、患者肿瘤直径＞20 mm和≤20 mm之间有统计学差异(P＜0.05);而在淋巴结转移阴性和阳性、雌激素受体阴性和阳性之间均无统计学意义.(2)乳腺癌组血浆循环DNA浓度明显高于乳腺良性病变组和正常对照组, 相比较有统计学差异(P＜0.05);而良性病变组血浆循环DNA浓度高于正常对照组, 但差异无统计学意义.(3)以血浆循环DNA≤12.90 μg/L作为诊断乳腺癌的临界值, 其检测灵敏度为85.0%, 特异度为88.3%, 准确度为87.1%.(4)Roc曲线下面积(AUC)为0.879, 95%可信区间为0.830～0.928.结论:乳腺癌患者的血浆DNA水平与疾病的发生、发展和预后密切相关, 血浆DNA水平有助于乳腺癌的鉴别诊断.     

鼻咽癌组织中DNA损伤与EB病毒感染的相关性研究

目的分析鼻咽癌(NPC)组织磷酸化组蛋白H2AX(γ-H2AX)的表达水平和EB病毒(EBV)的感染情况,探寻二者的相关性。并用细胞实验进行验证,以阐明EBV诱导DNA损伤应答进而促进NPC发生发展的可能机制。方法选取NPC标本50例和鼻咽炎(NPI)20例,采用免疫组化法检测γ-H2AX及EB病毒潜伏膜蛋白1(LMP1)的表达,对LMP1阴性标本采用原位杂交方法检测EB病毒编码的RNA(EBER);采用Western blot法检测EBV感染鼻咽癌细胞CNE1后γ-H2AX表达的变化。结果NPC组γ-H2AX的阳性率达94%,显著高于NPI组的40%;EBV阳性率为94%,显著高于NPI组的30%;97.9%EBV感染的NPC组织γ-H2AX阳性,二者表达有相关性(P0.05)。通过Western blot法检测进一步验证,EBV感染可使CNE1中γ-H2AX的表达量增高。结论γ-H2AX表达和EB病毒感染有密切关联性,EBV感染可能是通过诱导细胞DNA损伤,造成基因组不稳定从而促进NPC的发生发展。     

Livin在鼻咽癌中的表达及临床意义

目的：探讨鼻咽癌组织中凋亡抑制基因Livin的表达及其与鼻咽癌临床指标间的关系.方法：研究组为鼻咽癌患者56例,其中TNM分期早期患者（Ⅰ期＋Ⅱ期）39例,晚期（Ⅲ期＋Ⅳ期）17例 伴有淋巴结转移36例,无淋巴结转移20例.对照组为鼻咽部慢性炎症患者30例.采用半定量RT - PCR法分析两组之间Livin mRNA的表达情况,以及研究组内不同分期、有无淋巴结转移等情况下Livin mRNA表达的变化.结果：RT- PCR显示鼻咽癌组织中Livin mRNA呈阳性表达（阳性率91.1% ）,而鼻咽部慢性炎症组织中无表达,两组间相对表达量差异有统计学意义（P＜0.05）.研究组中有淋巴结转移组Livin mRNA相对表达量高于无淋巴转移组（P＜0.05） 不同TNM分期患者的Livin mRNA相对表达量,早期患者（Ⅰ期＋Ⅱ期）的阳性表达率为89.7%,明显低于晚期患者（Ⅲ期＋ Ⅳ期）阳性率94.1%,两组间差异有统计学意义（P＜0.05）.结论：Livin在鼻咽癌的发生、发展与转移中扮演重要角色,可能成为鼻咽癌早期诊断的分子指标及分子靶向治疗的新靶点.     

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.     

Role of Epstein-Barr virus DNA measurement in plasma in the clinical management of nasopharyngeal carcinoma in a low risk area

OBJECTIVE: To evaluate the role of quantitative measurement of Epstein-Barr virus (EBV) DNA in the clinical management of nasopharyngeal carcinoma (NPC) in a low tumour risk area (western Europe). METHODS: 22 consecutive Dutch NPC patients (11 europid) were studied. EBV DNA load in pretreatment and post-treatment plasma samples was determined. Three patients were also sampled at frequent intervals during treatment. RNA in situ hybridisation for the detection of EBV encoded RNAs (EBERs) was carried out on tumour biopsies of all cases. RESULTS: All patients with EBER positive NPC (20/22) showed a positive EBV DNA load in plasma at the time of diagnosis (median EBV DNA level, 4.1 log(10) copies/ml). Patients with EBER negative NPC had no detectable EBV DNA in plasma. After treatment, complete remission was achieved in all cases and concurrently EBV DNA in plasma became undetectable in all patients. In the three longitudinally evaluated cases, EBV DNA load gradually declined towards undetectable levels within three weeks after start of treatment. Two patients developed a distant metastasis with concomitant increases in EBV viral load. In addition, one EBER positive patient developed an EBER negative metastasis in the neck during follow up and in this case EBV DNA load remained undetectable at the time of recurrence. CONCLUSIONS: Plasma EBV DNA load measurement appears to be useful in a low tumour risk area. However, development of local recurrences may not always coincide with raised levels of EBV DNA.     

Quantitative plasma/serum EBV DNA load by LMP2A determination in an Italian cohort of NPC patients.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is frequently associated with Epstein-Barr virus (EBV), but little is known about the EBV DNA prevalence on peripheral blood in Western Countries, where the tumour is not endemic and its incidence is low. OBJECTIVES: To set up and evaluate an internally controlled qualitative polymerase chain reaction (PCR) followed by quantitative competitive PCR for the detection of EBV DNA in clinical specimens. To investigate whether EBV DNA load in peripheral blood was a consistent feature of Italian NPC patients. MATERIALS AND METHODS: A PCR assay based on latent membrane protein 2A (LMP2A) sequence amplification was chosen. Best assay conditions, sensitivity and reproducibility were determined. Sixty-four sera and 63 plasma from an Italian cohort of 39 NPC patients were analyzed. Samples from 5 patients followed up after radiotherapy were also assayed. Qualitative and quantitative beta-globin amplification was performed in parallel in order to provide an independent control for amplification competence of DNA and to investigate whether EBV DNA levels could be due to intracellular EBV viral genomes from cells lysed during plasma/serum collection. RESULTS: Twenty-five patients had undifferentiated carcinoma (UC) and 14 squamous cell carcinoma (SCC). EBV DNA has been quantified in 58 and 9% of the UC and SCC cases, respectively. No statistically significative differences were observed between the EBV DNA levels (469 vs 750 copies/ml, P=0.16) and prevalence (64 vs 57%, chi2(1)=0.22, P=0.64) in plasma and serum samples. Increased EBV viremia was found in patients with considerable extension of the primary tumour (172 vs 2250 copies/ml, low vs high tumour burden). Three UC subjects, which had detectable pre-treatment EBV DNA levels, became negative after radiotherapy. Clinical examination revealed that all had complete tumour regression. CONCLUSIONS: These PCR procedures allow an accurate and reproducible estimation of plasma/serum EBV DNA load in NPC patients living in non endemic areas, being strictly associated with UC WHO III and with tumour severity.     

Prognostic significance of Epstein-Barr virus viral load in patients with T1-T2 nasopharyngeal cancer

Nasopharyngeal cancer (NPC) is highly prevalent in southern Chinese populations but it is rare in most parts of the world. A few studies were performed in nonendemic regions of the world, and suggested the prognostic value of Epstein-Barr virus (EBV) DNA load in blood. In this study, EBV DNA presence and viral load (VL) level in the blood of patients with NPC in Polish population were presented. In addition, its prognostic value for locoregional control among other clinicopathological features was evaluated. Patients with carcinoma of the nasopharynx treated definitively with radiotherapy or radiochemotherapy were included in the study. Real-time polymerase chain reaction was performed for quantitating of EBV DNA in plasma. Among patients with NPC, 51% (22 of 43) were classified as EBV-positive with the mean of the VL of 4934 ± 8693 copies/mL. Multiple regression analysis between log EBV DNA VL and clinical parameters revealed that the most important factors increasing the VLs were advanced N disease together with no-smoking status and advanced T tumors. Multivariate Cox regression analysis revealed that T3-T4 tumors were an independent prognostic factor for poor locoregional control. Analysis for the subgroup of patients with T1-T2 tumors showed that T1-T2 EBV-negative patients had better locoregional control compared with T1-T2 EBV-positive, though without statistical significance. In conclusion, it seems that EBV DNA determination may have an important role in diagnostics of patients with NPC with T1-T2 tumors indicating a subgroup with poorer prognosis, though it needs to be proven on a larger cohort.     

Clinical implications of hepatitis B viral infection in Epstein–Barr virus-associated nasopharyngeal carcinoma

BackgroundLittle is known about the clinical implication of hepatitis B virus (HBV) infection in Epstein–Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC).ObjectiveThis study aimed to investigate the clinical characteristics and prognostic factors in patients with newly-diagnosed NPC with HBV infection.Study designA total of 722 patients with pathologically-diagnosed NPC who received comprehensive treatment at First People's Hospital of Foshan between June 2006 and December 2011 were enrolled in this retrospective study; 79 and 643 patients were HBsAg(+) and HBsAg(−), respectively. The correlations between HBV (HBsAg status and HBV DNA load) and EBV DNA were analyzed, further long-term survival and prognostic factors also were explored.ResultsWe reported NPC patients with HBsAg(+) represented worse outcome, and distant-failure especially liver metastasis was more common in these patients. HBV infection was more frequent in younger patients and male patients. No correlation was observed between the pre-treatment plasma EBV DNA load (cutoff, 1500 copies/ml) and HBsAg status (positive or negative; r = −0.036, P = 0.392), or the pre-treatment plasma EBV DNA load and HBV DNA load (r = 0.042, P = 0823).ConclusionsBoth HBV and EBV infection is an independent negative prognostic factor for long-term survival, distant metastasis, especially liver metastasis, was more common in NPC patients with HBsAg(+), and it seemed no link between EBV DNA load and HBsAg status in NPC.     

Plasma Epstein–Barr virus DNA as an archetypal circulating tumour DNA marker

Analysis of circulating tumour DNA (ctDNA), as one type of ‘liquid biopsy’, has recently attracted great attention. Researchers are exploring many potential applications of liquid biopsy in many different types of cancer. In particular, it is of biological interest and clinical relevance to study the molecular characteristics of ctDNA. For such purposes, plasma Epstein–Barr virus (EBV) DNA from patients with nasopharyngeal carcinoma (NPC) would provide a good model to understand the biological properties and clinical applications of ctDNA in general. The strong association between EBV and NPC in endemic regions has made plasma EBV DNA a robust biomarker for this cancer. There are many clinical utilities of plasma EBV DNA analysis in NPC diagnostics. Its role in prognostication and surveillance of recurrence is well established. Plasma EBV DNA has also been validated for screening NPC in a recent large-scale prospective study. Indeed, plasma EBV DNA could be regarded as an archetypal ctDNA marker. In this review, we discuss the biological properties of plasma EBV DNA from NPC samples and also the clinical applications of plasma EBV DNA analysis in the management of NPC. Of note, the recently reported size analysis of plasma EBV DNA in patients with NPC has highlighted size as an important analytical parameter of ctDNA and demonstrated clinical value in improving the diagnostic performance of an EBV DNA-based NPC screening test. Such insights into ctDNA analysis (including size profiling) may help its full potential in cancer diagnostics for other types of cancer to be realised. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

PET-CT 与 MRI 诊断中国人鼻咽癌转移的 Meta 分析简

目的通过Meta分析比较正电子计算机断层摄影术-计算机X线体层摄影术（PET—CT）与MRI对中国人鼻咽癌转移的诊断价值。方法用计算机检索万方数据库、中国学术期刊网全文数据库（CNKI）和维普数据库从1989年1月至2013年5月收录的PET-CT与MRI诊断中国人鼻咽癌转移的临床文献．对纳入文献采用Meta—Disc软件进行Meta分析。结果最终纳人文献5篇,共636例患者。Meta分析结果显示。PET—CT诊断鼻咽癌转移95％可信区间（CI）的灵敏度（SEN）、特异度（SPE）分别为35％（33％。37％）、94％（91％～96％）,受试者工作特征（SROC）曲线下面积（AUC）为0．7247．标准误（SE）（AUC）为0．2399;而MRI诊断鼻咽癌转移95％CI的SEN、SPE分别为35％（33％～37％）、84％（80％～87％）．SROCAUC为0．7654,SE（AUC）为0．1154。以上结果表明．与MRI相比,PET-CT在中国人鼻咽癌转移诊断中具有较低的误诊率．但诊断价值稍低。结论根据现有的临床诊断文献．PET—CT和MRI均是诊断中国人鼻咽癌转移的有效技术手段。在误诊率方面．PET—CT优于MRI;但诊断价值稍低。因此,两者紧密结合才能使鼻咽癌转移的检出率明显增高。     

新辅助化疗联合放疗治疗局限性晚期宫颈癌的临床疗效观察

目的分析新辅助化疗联合放疗治疗局限性晚期宫颈癌的有效性与安全性。方法临床收集84例局限性晚期宫颈癌患者,随机分成2组,对照组（44例）采用新辅助化疗方法治疗,治疗组（40例）均采用新辅助化疗联合放疗治疗,疗程结束后比较并评价两种治疗方法的有效性与安全性。结果治疗后临床观察结果显示,新辅助化疗联合放疗治疗局限性晚期宫颈癌近期观察是安全和有效的,有效率达到95%,与单纯新辅助化疗组相比具有显著的统计学差异（P〈0.05）。结论新辅助化疗联合放疗治疗局限性晚期宫颈癌是有效的,同时具有很好的耐受性。     

多目标优化方法在鼻咽癌临床中的剂量学研究

目的：比较鼻咽癌（NPC）多目标优化方法（MCO）和单目标优化方法（SCO）的计划质量及治疗实施效率。方法：对8例NPC患者以相同的处方剂量，但分别采用MCO和SCO设计7个野的静态调强（IMRT）计划。比较两种计划在剂量分布、靶区适形指数（CI）与均匀性指数（HI），不同危及器官（OAR）的剂量以及治疗计划的执行时间的差异。结果：两种优化方法均能满足临床剂量要求，与SCO相比，MCO计划组靶区PTV60。适形指数CI略优（p=0．007），靶区PTVk最大剂量D：％略高（p=o．019）。在PTV70.4上，MCO和SCO的HI及CI数分别为0．11、0．10和O．94、0．93，两者无显著性差异。MCO计划组危及器官剂量均比SCO组低（t=2．2～-13．3,p=0．000-0．044）。其中脑干、视交叉、视神经的平均剂量有30％以上的差异性。MCO和SCO计划组总子野数和总机器跳数（MU）分别为39（±3）个、648（±62）MU和43（±2）个、758（±68）MU（t=3．0、-3．5，p=0．020、0．011），MCO组分别减少了10％和17％。结论：使相比于SCO，用多目标优化方法（MCO）可实现靶区相同覆盖的同时可以更好的保护危及器官，且可提高治疗效率。     

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.