Serologic Response to the Epstein-Barr Virus Peptidome and the Risk for Multiple Sclerosis.

Importance: It remains unclear why only a small proportion of individuals infected with the Epstein-Barr virus (EBV) develop multiple sclerosis (MS) and what the underlying mechanisms are. Objective: To assess the serologic response to all EBV peptides before the first symptoms of MS occur, determine whether the disease is associated with a distinct immune response to EBV, and evaluate whether specific EBV epitopes drive this response. Design, Setting, and Participants: In this prospective, nested case-control study, individuals were selected among US military personnel with serum samples stored in the US Department of Defense Serum Repository. Individuals with MS had serum collected at a median 1 year before onset (reported to the military in 2000-2011) and were matched to controls for age, sex, race and ethnicity, blood collection, and military branch. No individuals were excluded. The data were analyzed between September 1, 2022, and August 31, 2023. Exposure: Antibodies (enrichment z scores) to the human virome measured using VirScan (phage-displayed immunoprecipitation and sequencing). Main Outcome and Measure: Rate ratios (RRs) for MS for antibodies to 2263 EBV peptides (the EBV peptidome) were estimated using conditional logistic regression, adjusting for total anti-EBV nuclear antigen 1 (EBNA-1) antibodies, which have consistently been associated with a higher MS risk. The role of antibodies against other viral peptides was also explored. Results: A total of 30 individuals with MS were matched with 30 controls. Mean (SD) age at sample collection was 27.8 (6.5) years; 46 of 60 participants (76.7%) were male. The antibody response to the EBV peptidome was stronger in individuals with MS, but without a discernible pattern. The antibody responses to 66 EBV peptides, the majority mapping to EBNA antigens, were significantly higher in preonset sera from individuals with MS (RR of highest vs lowest tertile of antibody enrichment, 33.4; 95% CI, 2.5-448.4; P for trend = .008). Higher total anti-EBNA-1 antibodies were also associated with an elevated MS risk (top vs bottom tertile: RR, 27.6; 95% CI, 2.3-327.6; P for trend = .008). After adjusting for total anti-EBNA-1 antibodies, risk estimates from most EBV peptides analyses were attenuated, with 4 remaining significantly associated with MS, the strongest within EBNA-6/EBNA-3C, while the association between total anti-EBNA-1 antibodies and MS persisted. Conclusion and Relevance: These findings suggest that antibody response to EBNA-1 may be the strongest serologic risk factor for MS. No single EBV peptide stood out as being selectively targeted in individuals with MS but not controls. Larger investigations are needed to explore possible heterogeneity of anti-EBV humoral immunity in MS.

Race-Dependent Differences in Risk, Genomics, and Epstein-Barr Virus Exposure in Monoclonal Gammopathies: Results of SWOG S0120.

PURPOSE: Risk of multiple myeloma is increased in African American (AA) populations compared with European American (EA) cohorts. Current estimates of risk of progression of monoclonal gammopathy of undetermined significance (MGUS) are based largely on studies in EA cohorts. Prospective analyses of this risk in AA cohorts are lacking. PATIENTS AND METHODS: Between 2003 and 2011, 331 eligible patients with IgG/A monoclonal gammopathy were enrolled in a prospective observational trial (SWOG S0120). RESULTS: Of 331 eligible patients, 57 (17%) were of AA descent. The risk of transformation to clinical malignancy in AA patients was significantly lower than in non-AA cohort (2-year risk 5% vs. 15%; 5-year risk 13% vs. 24%; log-rank P = 0.047). Differences in risk were evident for both MGUS and asymptomatic multiple myeloma. Gene expression profile (GEP) of CD138-purified plasma cells revealed that all molecular multiple myeloma subsets can be identified in both cohorts. However, the proportion of patients with high-risk GEP risk score (GEP-70 gene risk > -0.26) was lower in the AA cohort (0% vs. 33%, P = 0.01). AA cohorts also have higher levels of antibodies against Epstein-Barr nuclear antigen-1 (EBNA-1; P < 0.001). CONCLUSIONS: These data provide the first prospective evidence that multiple myeloma precursor states in AA patients may have lower risk of disease compared with non-AA counterparts with lower incidence of high-risk GEP and increased EBV seropositivity. Race-dependent differences in biology and clinical risk of gammopathy may impact optimal management of these patients.

Dermatomyositis Developed After Exposure to Epstein-Barr Virus Infection and Antibiotics Use.

Dermatomyositis is an inflammatory disorder involving muscle and skin. Similar to many other autoimmune diseases, environmental factors appear to trigger the onset of disease in some cases. Many drugs have been reported to be associated with dermatomyositis, and rarely infections have been described as potential triggering agents. Here we are describing a case of dermatomyositis that developed after doxycycline and levofloxacin use, who also had recent Epstein-Barr virus infection. Dermatomyositis associated with doxycycline or levofloxacin use has not yet been described in the literature, while reports of dermatomyositis after Epstein-Barr virus infection have been rare and limited to juvenile dermatomyositis or in association with cancer. It is important for clinicians to be aware of this rare association so that the diagnosis and treatment can be exercised promptly.

Vitamin D and other environmental risk factors in Colombian patients with multiple sclerosis.

OBJECTIVE: The aim of this study was to explore the association between MS and vitamin D levels, as well as Epstein-Barr virus (EBV) seropositivity and smoking history in a Colombian population. METHODS: We conducted a cross-sectional study between 2017 and 2018. We measured vitamin D levels and EBV antibody titers and administered a questionnaire to assess dietary habits, smoking, second-hand smoking and duration of smoking, sunlight exposure, physical activity, and personal and family history in individuals with and without multiple sclerosis during adolescence. A multivariable logistic regression model was then performed to explore the association between vitamin D status and MS. RESULTS: A total of 87 individuals with MS (mean age 40.9 years; 65.52% females) and 87 without MS (mean age 55 years; 65.52% females) were included in the analysis. In the multivariable analysis, after controlling for supplementation vitamin D levels did not differ between both groups and no difference was found regarding tobacco smoke exposure. The proportion of individuals who tested positive for anti-EBV nuclear antigen was significantly higher in individuals with MS (95.4% vs 82.76%, p = 0.028) CONCLUSION: : We did not find a statistically significant association between MS and vitamin D levels while anti-EBV nuclear antigen titers behaved as previously described in the literature. This study provides new evidence of the association between MS and different risk factors in our country, reinforcing the hypothesis that the pathogenesis of MS is multifactorial. Further studies are needed to better define the association between environmental factors and the development of MS in low prevalence areas.

EBNA1, EBNA2, and EBNA3 link Epstein-Barr virus and hypovitaminosis D in multiple sclerosis pathogenesis.

A strong north-to-south gradient is observed in the distribution of multiple sclerosis (MS), hinting toward an environmental etiology. Vitamin D has been associated with a decreased incidence of MS and may explain, in part, the lower prevalence in tropical climates. However, the existence of MS epidemics implies the possibility of an infectious etiology. Epstein-Barr virus (EBV) infection precedes MS presentation in nearly all affected individuals. While the individual contribution of EBV, vitamin D deficiency, and specific risk genes to MS etiology is possible, their potential interaction is of great interest and may have a synergistic effect on the development of MS.

Is triple-positive serology for Epstein-Barr virus (VCA-IgG, VCA-IgM, EBNA-IgG) a specific feature of angioimmunoblastic T-cell lymphoma?

PURPOSE: We assessed the frequency of triple-positive serology (viral capsid antigen [VCA]-immunoglobulin G [IgG], VCA-immunoglobulin M, Epstein-Barr nuclear antigen-IgG) for Epstein-Barr virus (EBV) in a small number of patients with angioimmunoblastic T-cell lymphoma (AITL) at disease onset. METHODS: Nine patients with newly diagnosed AITL were retrospectively enrolled in the present study. For all of them, EBV serology data were available. RESULTS: Of 9 patients, 7 (77.7%) had a triple-positive serology (VCA-IgG, VCA-IgM, EBNA-IgG ) for EBV. These patients were characterized by bone marrow involvement, high incidence of thrombocytopenia, and poor prognosis according to Revised International Prognostic Index and Prognostic Index for Angioimmunoblastic T-cell Lymphoma scores. CONCLUSION: Assessment of both viremia and serology for EBV could be useful in patients with clinical and laboratory data suggesting lymphoma diagnosis; furthermore, although our data need to be validated in a larger cohort of patients, triple positivity for EBV serology might help to direct the diagnosis toward AITL.

Exploring the effect of vitamin D3 supplementation on the anti-EBV antibody response in relapsing-remitting multiple sclerosis.

BACKGROUND: Epstein-Barr virus (EBV) infection and vitamin D insufficiency are potentially interacting risk factors for multiple sclerosis (MS). OBJECTIVES: To investigate the effect of high-dose vitamin D3 supplements on antibody levels against the EBV nuclear antigen-1 (EBNA-1) in patients with relapsing-remitting multiple sclerosis (RRMS) and to explore any underlying mechanism affecting anti-EBNA-1 antibody levels. METHODS: This study utilized blood samples from a randomized controlled trial in RRMS patients receiving either vitamin D3 (14,000 IU/day; n = 30) or placebo ( n = 23) over 48 weeks. Circulating levels of 25-hydroxyvitamin-D, and anti-EBNA-1, anti-EBV viral capsid antigen (VCA), and anti-cytomegalovirus (CMV) antibodies were measured. EBV load in leukocytes, EBV-specific cytotoxic T-cell responses, and anti-EBNA-1 antibody production in vitro were also explored. RESULTS: The median antibody levels against EBNA-1, but not VCA and CMV, significantly reduced in the vitamin D3 group (526 (368-1683) to 455 (380-1148) U/mL) compared to the placebo group (432 (351-1280) to 429 (297-1290) U/mL; p = 0.023). EBV load and cytotoxic T-cell responses were unaffected. Anti-EBNA-1 antibody levels remained below detection limits in B-cell cultures. CONCLUSION: High-dose vitamin D3 supplementation selectively reduces anti-EBNA-1 antibody levels in RRMS patients. Our exploratory studies do not implicate a promoted immune response against EBV as the underlying mechanism.

Epstein-Barr virus, cytomegalovirus, and multiple sclerosis susceptibility: A multiethnic study.

OBJECTIVE: To determine whether Epstein-Barr virus (EBV) or cytomegalovirus (CMV) seropositivity is associated with multiple sclerosis (MS) in blacks and Hispanics and to what extent measures of the hygiene hypothesis or breastfeeding could explain these findings. EBV and CMV have been associated with MS risk in whites, and the timing and frequency of both viruses vary by factors implicated in the hygiene hypothesis. METHODS: Incident cases of MS or its precursor, clinically isolated syndrome (CIS), and matched controls (blacks, 111 cases/128 controls; Hispanics, 173/187; whites, 235/256) were recruited from the membership of Kaiser Permanente Southern California. Logistic regression models accounted for HLA-DRB1*1501 status, smoking, socioeconomic status, age, sex, genetic ancestry, and country of birth. RESULTS: Epstein-Barr nuclear antigen-1 (EBNA-1) seropositivity was independently associated with an increased odds of MS/CIS in all 3 racial/ethnic groups (p < 0.001 for blacks and whites, p = 0.02 for Hispanics). In contrast, CMV seropositivity was associated with a lower risk of MS/CIS in Hispanics (p = 0.004) but not in blacks (p = 0.95) or whites (p = 0.96). Being born in a low/middle-income country was associated with a lower risk of MS in Hispanics (p = 0.02) but not after accounting for EBNA-1 seropositivity. Accounting for breastfeeding did not diminish the association between CMV and MS in Hispanics. CONCLUSIONS: The consistency of EBNA-1 seropositivity with MS across racial/ethnic groups and between studies points to a strong biological link between EBV infection and MS risk. The association between past CMV infection and MS risk supports the broader hygiene hypothesis, but the inconsistency of this association across racial/ethnic groups implies noncausal associations.

Effect of high-dose vitamin D3 supplementation on antibody responses against Epstein-Barr virus in relapsing-remitting multiple sclerosis.

BACKGROUND: Elevated antibody levels against Epstein-Barr virus (EBV) and a poor vitamin D status are environmental factors that may interact in relapsing-remitting multiple sclerosis (RRMS) aetiology. OBJECTIVES: To examine effects of high-dose oral vitamin D3 supplementation on antibody levels against EBV nuclear antigen 1 (EBNA1) in RRMS. METHODS: Serum 25-hydroxyvitamin D3 (25(OH)D) and immunoglobulin G antibody levels against EBNA1 (whole protein and amino acid 385-420 fragment), EBV viral capsid antigen (VCA), cytomegalovirus (CMV) and varicella zoster virus (VZV) were measured in 68 RRMS patients enrolled in a 96-week randomised double-blinded placebo-controlled clinical trial of oral vitamin D3 supplementation (20,000 IU/week) (NCT00785473). RESULTS: The mean 25(OH)D level more than doubled in the vitamin D group and was significantly higher than in the placebo group at study conclusion (123.2 versus 61.8 nmol/L, p < 0.001). Compared to the placebo group, both anti-EBNA1 protein and fragment antibody levels decreased in the vitamin D group from baseline to week 48 ( p = 0.038 and p = 0.004, respectively), but not from baseline to week 96. Vitamin D3 supplementation did not affect antibodies against VCA, CMV or VZV. CONCLUSION: The results indicate that high-dose oral vitamin D3 supplementation can affect humoral immune responses against the latent EBV antigen EBNA1 in RRMS.

The increased antibody response to Epstein-Barr virus in multiple sclerosis is restricted to selected virus proteins.

Multiple sclerosis (MS) is associated with Epstein-Barr virus (EBV) infection, and the antibody response to EBV is reported to be increased in MS. EBV contains multiple antigens, and only a few have been investigated. Our hypothesis is that MS patients will have an increased antibody response to only selected EBV antigens. We used immunoprecipitation and quantitative mass spectrometry to identify candidate EBV antigens. We then measured the antibody response to 10 individual EBV proteins with quantitative ELISA. We found that the antibody response was increased in MS to three of the EBV proteins, but not to the other seven.

The Index of Vulnerability: An anthropological method linking social-ecological systems to mental and physical health outcomes.

Researchers need measures of vulnerability that are grounded in explicit theoretical and conceptual frameworks, that are sensitive to local contexts, and that are easy to collect. This paper presents the Index of Vulnerability (IoV), a quantitative yet anthropologically-informed method connecting social-ecological systems to mental and physical health outcomes. The IoV combines measures of five life domains; food insecurity, water insecurity, access to healthcare, social support, and social status. Scores on this index increase for each life domain where the individual falls into a "high risk" category. Thus, individuals with the highest IoV scores are those who are at risk across multiple life domains. This approach makes the IoV malleable to local contexts, as scholars can choose which measure of each life domain is most appropriate for their study population. An anthropological study conducted among 225 Awajún adults living in the Peruvian Amazon from March to November of 2013 showed that men with higher IoV scores had significantly lower summary fat skinfolds, lower triglyceride levels, and a greater probability of reporting moderate to severe somatic symptoms and poor perceived health. Awajún women with higher IoV scores had significantly elevated perceived stress levels and a greater probability of reporting poor perceived health and moderate to severe somatic and depressive symptoms. Importantly, comparing the IoV to its constituent parts shows that it predicts a wider range of mental and physical health outcomes than any of the life domains alone. The IoV is presented here in relation to the broader political-economic and cultural context of the Awajún, forwarding a critical biocultural approach within anthropology, and demonstrating the IoV's utility for other scholars and practitioners.

Vitamin D, HLA-DRB1 and Epstein-Barr virus antibody levels in a prospective cohort of multiple sclerosis patients.

BACKGROUND AND PURPOSE: Our objective was to study the association between serum levels of anti Epstein-Barr virus nuclear antigen 1 (EBNA-1) antibody and 25-hydroxyvitamin D (25(OH)D) in a prospective cohort of patients with relapsing-remitting multiple sclerosis. METHOD: The study comprised 90 patients with relapsing-remitting multiple sclerosis, all participants in a randomized clinical trial of ω-3 fatty acids (the OFAMS study). Repeated, paired measurements of serum 25(OH)D and serum EBNA-1 immunoglobulin G (IgG) levels were obtained at baseline and every 6 months for 24 months. The association between serum EBNA-1 IgG and serum 25(OH)D levels was analysed using generalized linear models for hierarchical data. RESULTS: There was a significant variation in EBNA-1 IgG antibody level between sampling months (Fdf 11 = 1.8, P = 0.043, one-way anova). There was a negative association between EBNA-1 IgG and 25(OH)D [B = -0.230, 95% confidence interval (CI) (-0.440, -0.023), P = 0.030] and a positive association between EBNA-1 IgG and HLA-DRB1*15 positive status [B = 94.7, 95% CI (2.423, 186.9), P = 0.044]. The association between 25(OH)D and EBNA-1 IgG remained significant after adjusting for the patient's age, gender, HLA-DRB1*15, retinol levels and interferon ß-1a treatment. CONCLUSION: Our study demonstrates monthly differences in EBNA-1 IgG levels and an association between EBNA-1 IgG, 25(OH)D levels and HLA-DRB1*15. These results indicate that EBNA-1 IgG serum levels are affected by genetic and environmental factors that also modulate multiple sclerosis risk.

The low EOMES/TBX21 molecular phenotype in multiple sclerosis reflects CD56+ cell dysregulation and is affected by immunomodulatory therapies.

Multiple Sclerosis (MS) is an autoimmune disease treated by therapies targeting peripheral blood cells. We previously identified that expression of two MS-risk genes, the transcription factors EOMES and TBX21 (ET), was low in blood from MS and stable over time. Here we replicated the low ET expression in a new MS cohort (p<0.0007 for EOMES, p<0.028 for TBX21) and demonstrate longitudinal stability (p<10(-4)) and high heritability (h(2)=0.48 for EOMES) for this molecular phenotype. Genes whose expression correlated with ET, especially those controlling cell migration, further defined the phenotype. CD56+ cells and other subsets expressed lower levels of Eomes or T-bet protein and/or were under-represented in MS. EOMES and TBX21 risk SNP genotypes, and serum EBNA-1 titres were not correlated with ET expression, but HLA-DRB1*1501 genotype was. ET expression was normalised to healthy control levels with natalizumab, and was highly variable for glatiramer acetate, fingolimod, interferon-beta, dimethyl fumarate.

Comparison of Circulating Tumour Cells and Circulating Cell-Free Epstein-Barr Virus DNA in Patients with Nasopharyngeal Carcinoma Undergoing Radiotherapy.

Quantification of Epstein-Barr virus (EBV) cell-free DNA (cfDNA) is commonly used in clinical settings as a circulating biomarker in nasopharyngeal carcinoma (NPC), but there has been no comparison with circulating tumour cells (CTCs). Our study aims to compare the performance of CTC enumeration against EBV cfDNA quantitation through digital PCR (dPCR) and quantitative PCR. 74 plasma samples from 46 NPC patients at baseline and one month after radiotherapy with or without concurrent chemotherapy were analysed. CTCs were captured by microsieve technology and enumerated, while three different methods of EBV cfDNA quantification were applied, including an in-house qPCR assay for BamHI-W fragment, a CE-IVD qPCR assay (Sentosa ®) and a dPCR (Clarity™) assay for Epstein-Barr nuclear antigen 1 (EBNA1). EBV cfDNA quantitation by all workflows showed stronger correlation with clinical stage, radiological response and overall survival in comparison with CTC enumeration. The highest detection rate of EBV cfDNA in pre-treatment samples was seen with the BamHI-W qPCR assay (89%), followed by EBNA1-dPCR (85%) and EBNA1-qPCR (67%) assays. Overall, we show that EBV cfDNA outperforms CTC enumeration in correlation with clinical outcomes of NPC patients undergoing treatment. Techniques such as dPCR and target selection of BamHI-W may improve sensitivity for EBV cfDNA detection.

Can Epstein-Barr virus DNA load in nasopharyngeal brushings or whole blood predict recurrent nasopharyngeal carcinoma in a non-endemic region? A prospective nationwide study of the Dutch Head and Neck Oncology Cooperative Group.

This study estimated the value of quantitative measurements of EBV markers in the clinical management of nasopharyngeal carcinoma in a non-endemic area. The aim was to predict prognosis and detect recurrent and residual disease. In 72 patients, EBV DNA load in blood and nasopharyngeal brushes, and IgA VCA-p18 and EBNA1 in plasma were measured at different time points. At diagnosis and post-treatment, a cut-off value was used for detecting disease [positive (PPV) and negative (NPV) predictive value]. The markers were correlated as a continuous variable with tumor stage, disease-free survival (DFS) and overall survival (OS). The Cox hazard ratio model assessed hazard ratios. At diagnosis, the markers were above the COV in 45, 92, 85 and 83 % of the patients, respectively. Post-treatment, DNA load test in blood and brush had the best discriminating power (blood DNA load test: PPV 39 % and NPV 97 %, brush for local disease: PPV 75 % and NPV 99 %). Post-treatment, DNA load in blood was the best predictor for OS and DFS [hazard ratio 3.2 (95 % CI 1.51-3.5) and 2.3 (95 % CI 1.72-5.8)]. Assessing the EBV DNA load in blood has significant prognostic value, although the clinical value is for discussion. The EBV DNA load in the brush might improve early detection of local failures post-treatment.

Epstein-Barr virus and Interleukin-28B polymorphism in the prediction of response to interferon therapy in hepatitis C patients.

BACKGROUND AND STUDY AIMS: In chronic hepatitis C virus (HCV), viral and host factors are known to be predictors for anti-viral therapy. IL-28B genotype strongly influences treatment outcome, while Epstein-Barr virus (EBV) co-infection could accelerate the course of chronic HCV infection. This study was conducted to assess whether EBV co-infection adds to the predictive value of IL-28B. PATIENTS AND METHODS: A total of 105 patients with chronic HCV were classified according to their response to treatment into two groups: 38 sustained virological responders (SVRs) and 67 nonresponders (NRs). Collected sera at baseline and follow-up (FUP) were used for assessing EBV antibodies by enzyme-linked immunosorbent assay (ELISA) and the expression of EBV genes (BNLF-1, BZLF-1, and EBER-2) by polymerase chain reaction (PCR). Collected peripheral blood was used for detecting IL-28B rs.12979860 single-nucleotide polymorphism. RESULTS: Regarding IL-28B genotype frequencies, a significant difference (p=0.003) was observed between SVRs (C/C=51.4%, C/T=48.6%, T/T=0%) and NRs (C/C=25%, C/T=55%, T/T=20%). On assessing EBV infection at baseline and FUP, it was found that 61% and 55% were positive, respectively, with no significant difference between SVRs and NRs. As for anti-viral capsid antigen (VCA) antibodies, the NRs had significantly higher baseline anti-VCA immunoglobulin M (IgM) levels than SVRs (p=0.01). While FUP anti-Epstein-Barr nuclear antigen-1 (EBNA-1) IgG reported a significant decline within SVR patients (p=0.02), neither baseline nor FUP anti-VCA IgG levels showed a statistically significant viral response. Finally, on comparing EBV markers with CC versus CT and TT genotypes, it was found that FUP anti-VCA IgG levels were significantly increased in CC genotype (p=0.003). CONCLUSION: Interleukin-28B polymorphism could be a possible predictor of response to pegylated interferon/ribavirin therapy (PEG-IFN/RBV). Furthermore, co-infection with EBV did not affect the response to IFN-based therapy in HCV-infected patients.

Association of serum Epstein-Barr nuclear antigen-1 antibodies and intrathecal immunoglobulin synthesis in early multiple sclerosis.

Multiple sclerosis (MS) is associated with Epstein-Barr virus (EBV) infection. A characteristic feature of MS is an intrathecal synthesis of immunoglobulin (Ig)G. In 90 patients with clinically isolated syndromes/early relapsing-remitting MS, serum antibodies to Epstein-Barr nuclear antigen-1, but not to EBV viral capsid antigen, rubella, or varicella zoster virus, were higher (p=0.03) in those with than those without a calculated intrathecal IgG synthesis >0% and correlated with the percentage (r=0.27, p=0.009) and concentration (r=0.27, p=0.012) of intrathecally produced IgG. These findings suggest a link between EBV infection and the events leading to intrathecal IgG synthesis in patients with MS.

[The clinical significance of serum Epstein-Barr virus-determined nuclear antigen 1 (EBNA1)/latent membrane protein 1 (LMP1) assay in patients with nasal type extranodal NK/T-cell lymphoma].

OBJECTIVE: To explore the clinical significance of the serum Epstein-Barr virus-determined nuclear antigen 1 (EBNA1)/latent membrane protein 1 (LMP1) in patients with extranodal NK/T-cell lymphoma, nasal type (ENKL). METHODS: The serum EBNA1 and LMP1 were detected by real-time PCR in 36 ENKL patients hospitalized in Beijing Tongren Hospital from August 2010 to August 2013. Twenty healthy volunteers were recruited as controls. RESULTS: The median serum EBNA1 was 1.9×10(4) (ranged from 0 to 11.0×10(4)) copies/µl in ENKL patients and 8.0 (ranged from 0 to 43.8) copies/µl in healthy volunteers. The median serum LMP1 was 3.9×10(3) (ranged from 118.3 to 24.0×10(3)) copies/µl in ENKL patients and 3.3 (ranged from 0 to 33.3) copies/µl in healthy volunteers. Both EBNA1 and LMP1 were higher in ENKL patients than healthy volunteers (all P < 0.01). The median EBNA1 and LMP1 in ENKL patients posttreatment were 1.0×10(3) (ranged from 0 to 2.0 × 10(3)) copies/µl and 300.8 (ranged from 0 to 825.7) copies/µl respectively, which were both significantly decreased than pretreatment (all P < 0.05). The EBNA1 and LMP1 were decreased in effective treatment group versus ineffective treatment group (P < 0.05). The serum EBNA1 and LMP1 were positively correlated with lactic dehydrogenase (LDH) level (r = 0.364,0.546; P = 0.040,0.012). CONCLUSIONS: (1) The measurement of EBNA1/LMP1 may be useful in evaluating the therapeutic effect. (2) The serum EBNA1/LMP1 may reflect the tumor load in ENKL patients.