Antibody responses to Epstein-Barr virus-encoded latent membrane protein-1 (LMP1) and expression of LMP1 in juvenile Hodgkin's disease

A phase I/II trial of brentuximab vedotin plus rituximab as frontline therapy for patients with immunosuppression-associated CD30+ and/or EBV + lymphomas

Treatment strategies for post-transplant lymphoproliferative disorders (PTLD) consist of response-adapted risk-stratified methods using immunosuppression reduction, immunotherapy, and chemotherapy. We investigated the efficacy of Brentuximab vedotin given concurrently with Rituximab (BV + R) once weekly for four weeks, followed by optional consolidation, and up to one year of maintenance. Among 20 assessable patients, BV + R therapy resulted in an overall response rate of 75% (95% CI 51 to 91, p = 0.044) with 60% achieving a complete response. Median time to best response was 28 days. Two-year progression-free survival and overall survival rates were 75 and 90%, respectively. Most common severe grade 3/4 treatment-related toxicities included neutropenia (40%), hypertension (30%), infection (25%), and peripheral neuropathy (15%). BV + R is a novel and effective therapeutic strategy that achieved rapid and durable remissions in previously untreated PTLD patients; however, this treatment platform requires further modification due to the high rates of treatment-related toxicity.Key pointsBrentuximab vedotin + Rituximab showed ORR and CR rates of 75 and 60% in patients with immunosuppression-associated lymphoid malignanciesHigh rates of treatment delay were attributed to treatment-related toxicity; further dosing optimization of this regimen is required.

Evaluation of the antibody response to the EBV proteome in EBV-associated classical Hodgkin lymphoma

The humoral immune response to Epstein-Barr virus (EBV) in classical Hodgkin lymphoma (cHL) stratified by EBV tumor status is unclear. We examined IgG and IgA antibody responses against 202 protein sequences representing 86 EBV proteins using a microarray and sera from 139 EBV-positive cHL cases, 70 EBV-negative cHL cases and 141 population-based controls frequency matched to EBV-positive cHL cases on sex and age by area (UK, Denmark and Sweden). We leveraged existing data on the proportion of circulating B-cells infected by EBV and levels of serum CCL17, a chemokine secreted by cHL tumor cells, from a subset of the cHL cases in the UK. Total IgG but not IgA response level was significantly different between EBV-positive cHL cases and controls. The distinct serological response included significant elevations in 16 IgG antibodies and 2 IgA antibodies, with odds ratios_{highest vs. lowest tertile > 3} observed for the following EBV proteins: LMP1 (oncogene), BcLF1 (VCAp160, two variants) and BBLF1 (two variants). Our cHL IgG signature correlated with the proportion of circulating EBV-infected B-cells, but not serum CCL17 levels. We observed no differences in the anti-EBV antibody profile between EBV-negative cHL cases and controls. BdRF1(VCAp40)-IgG and BZLF1(Zta)-IgG were identified as the serological markers best able to distinguish EBV-positive from EBV-negative cHL tumors. Our results support the hypothesis that differences in the EBV antibody profile are specific to patients with EBV-positive cHL and are not universally observed as part of a systematically dysregulated immune response present in all cHL cases.

Molecular diversity of IgG responses to Epstein-Barr virus proteins in asymptomatic Epstein-Barr virus carriers

The Epstein-Barr virus (EBV) is a ubiquitous pathogen that infects over 90 % of adults. EBV is the primary etiological agent of infectious mononucleosis and is closely associated with nasopharyngeal carcinoma, gastric carcinoma, Hodgkin lymphoma and Burkitt lymphoma. Clinical serological assays for EBV diagnosis only survey a small portion of the viral proteome, which does not represent the total antigenic breadth presented to the immune system during viral infection. In this study, we have generated an expression library containing the majority of EBV ORFs, and have systematically evaluated IgG responses to those EBV proteins in sera from EBV carriers. In addition to confirming previously recognized dominant EBV antigens, this study has identified additional immunodominant antigens, and has revealed a more expansive antigenic profile of the humoral responses to EBV in asymptomatic carriers. This EBV expression library will be deposited in a public repository with the goal of disseminating this new research tool for the application of identifying potential new biomarkers for EBV-associated diseases.

Phage Particles as Vaccine Delivery Vehicles: Concepts, Applications and Prospects

The development of new strategies for vaccine delivery for generating protective and long-lasting immune responses has become an expanding field of research. In the last years, it has been recognized that bacteriophages have several potential applications in the biotechnology and medical fields because of their intrinsic advantages, such as ease of manipulation and large-scale production. Over the past two decades, bacteriophages have gained special attention as vehicles for protein/peptide or DNA vaccine delivery. In fact, whole phage particles are used as vaccine delivery vehicles to achieve the aim of enhanced immunization. In this strategy, the carried vaccine is protected from environmental damage by phage particles. In this review, phage-based vaccine categories and their development are presented in detail, with discussion of the potential of phage-based vaccines for protection against microbial diseases and cancer treatment. Also reviewed are some recent advances in the field of phage- based vaccines.

Human serum antibodies against EBV latent membrane protein 1 cross-react with α-synuclein

Objectives:

To identify the epitope on α-synuclein (α-syn) to which antibodies against the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) bind and to determine whether antibodies targeting this mimicry domain are present in human sera.

Methods:

Reactivity of the α-syn-cross-reacting anti-LMP1 monoclonal antibody CS1-4 to a synthetic peptide containing the putative mimicry domain was compared to those in which this domain was mutated and to murine and rat α-syn (which differ from human α-syn at this site) in Western blots. Using ELISA, sera from EBV+ (n = 4) and EBV− (n = 12) donors as well as those with infectious mononucleosis (IM; n = 120), and Hodgkin disease (HD; n = 33) were interrogated for antibody reactivity to synthetic peptides corresponding to regions of α-syn and LMP1 containing the mimicry domain.

Results:

CS1-4 showed strong reactivity to wild-type human α-syn, but not to the mutant peptides or rodent α-syn. Control EBV− and EBV+ sera showed no reactivity to α-syn or LMP1 peptides. However, a significant proportion of IM and HD sera contained immunoglobulin M (IgM) (59% and 70%, in IM and HD, respectively), immunoglobulin G (IgG) (40% and 48%), and immunoglobulin A (IgA) (28% and 36%) antibodies to both peptides, as well as a significant correlation in the titers of IgM (ρ = 0.606 and 0.664, for IM and HD, respectively), IgG (0.526 and 0.836), and IgA (0.569 and 0.728) antibodies targeting LMP1 and α-syn peptides.

Conclusions:

Anti-EBV-LMP1 antibodies cross-reacting with a defined epitope in α-syn are present in human patients. These findings may have implications for the pathogenesis of synucleinopathies.

Epstein-Barr Virus-Specific Humoral Immune Responses in Health and Disease

Epstein-Barr virus (EBV) is widely distributed in the world and associated with a still increasing number of acute, chronic, malignant and autoimmune disease syndromes. Humoral immune responses to EBV have been studied for diagnostic, pathogenic and protective (vaccine) purposes. These studies use a range of methodologies, from cell-based immunofluorescence testing to antibody-diversity analysis using immunoblot and epitope analysis using recombinant or synthetic peptide-scanning. First, the individual EBV antigen complexes (VCA , MA, EA(D), EA(R) and EBNA) are defined at cellular and molecular levels, providing a historic overview. The characteristic antibody responses to these complexes in health and disease are described, and differences are highlighted by clinical examples. Options for EBV vaccination are briefly addressed. For a selected number of immunodominant proteins, in particular EBNA1, the interaction with human antibodies is further detailed at the epitope level, revealing interesting insights for structure, function and immunological aspects, not considered previously. Humoral immune responses against EBV-encoded tumour antigens LMP1, LMP2 and BARF1 are addressed, which provide novel options for targeted immunotherapy. Finally, some considerations on EBV-linked autoimmune diseases are given, and mechanisms of antigen mimicry are briefly discussed. Further analysis of humoral immune responses against EBV in health and disease in carefully selected patient cohorts will open new options for understanding pathogenesis of individual EBV-linked diseases and developing targeted diagnostic and therapeutic approaches.

Therapeutic implications of Epstein-Barr virus infection for the treatment of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is highly endemic in certain regions including the People’s Republic of China and Southeast Asia. Its etiology is unique and multifactorial, involving genetic background, epigenetic, and environment factors, including Epstein–Barr virus (EBV) infection. The presence of EBV in all tumor cells, aberrant pattern of antibodies against EBV antigens in patient sera, and elevated viral DNA in patient circulation as well as nasopharyngeal site underline the role of EBV during NPC development. In NPC tumors, EBV expresses latency type II, where three EBV-encoded proteins, Epstein–Barr nuclear antigen 1, latent membrane protein 1 and 2 (LMP1, 2), are expressed along with BamH1-A rightward reading frame 1, Epstein–Barr virus-encoded small nuclear RNAs, and BamH1-A rightward transcripts. Among all encoded proteins, LMP1 plays a central role in the propagation of NPC. Standard treatment of NPC consists of radiotherapy with or without chemotherapy for early stage, concurrent chemoradiotherapy in locally advanced tumors, and palliative systemic chemotherapy in metastatic disease. However, this standard care has limitations, allowing recurrences and disease progression in a certain proportion of cases. Although the pathophysiological link and molecular process of EBV-induced oncogenesis are not fully understood, therapeutic approaches targeting the virus may increase the cure rate and add clinical benefit. The promising results of early phase clinical trials on EBV-specific immunotherapy, epigenetic therapy, and treatment with viral lytic induction offer new options for treating NPC.

Atypical prediagnosis Epstein-Barr virus serology restricted to EBV-positive Hodgkin lymphoma

An altered anti-Epstein-Barr virus (EBV) serologic profile preceding diagnosis is associated with an increased risk of Hodgkin lymphoma. It is unknown whether this atypical pattern predicts Hodgkin lymphoma risk further subdivided by determination of EBV in tumor cells. A nested case-control study of 128 incident Hodgkin lymphoma cases and 368 matched controls from active-duty military personnel with archived serum in the US Department of Defense Serum Repository was conducted to determine whether a panel of anti-EBV antibody titers differed in EBV(+) and EBV(-) Hodgkin lymphoma. Among 40 EBV(+) Hodgkin lymphoma cases and matched controls, statistically significant increased risks were associated with elevated anti-EBV VCA IgG antibody titers (relative risk = 3.1; 95% confidence interval [CI], 1.1-8.7), and an anti-EBNA-1/anti-EBNA-2 antibody ratio ≤ 1.0 versus > 1.0 (relative risk = 4.7; 95% CI, 1.6-13.8). In contrast, no significant associations were found among 88 EBV(-) Hodgkin lymphoma cases relative to their matched controls. In case-case analysis, EBV(+) disease was significantly associated with a low anti-EBNA-1/anti-EBNA-2 antibody ratio. This distinctive serologic response to EBV latent antigens, indicative of immune dysfunction in other clinical settings, is associated with an increased risk of developing EBV(+) but not EBV(-) Hodgkin lymphoma.

Nasopharyngeal carcinoma in Indonesia: epidemiology, incidence, signs, and symptoms at presentation

Among all head and neck (H&N) cancers, nasopharyngeal carcinoma (NPC) represents a distinct entity regarding epidemiology, clinical presentation, biological markers, carcinogenic risk factors, and prognostic factors. NPC is endemic in certain regions of the world, especially in Southeast Asia, and has a poor prognosis. In Indonesia, the recorded mean prevalence is 6.2/100 000, with 13 000 yearly new NPC cases, but otherwise little is documented on NPC in Indonesia. Here, we report on a group of 1121 NPC patients diagnosed and treated at Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia between 1996 and 2005. We studied NPC incidence among all H&N cancer cases (n=6000) observed in that period, focusing on age and gender distribution, the ethnic background of patients, and the disease etiology. We also analyzed most prevalent signs and symptoms and staging of NPC patients at first presentation. In this study population, NPC was the most frequent H&N cancer (28.4%), with a male-to-female ratio of 2.4, and was endemic in the Javanese population. Interestingly, NPC appeared to affect patients at a relatively young age (20% juvenile cases) without a bimodal age distribution. Mostly, NPC initiated in the fossa of Rosenmuller and spreaded intracranially or locally as a mass in the head. Occasionally, NPC developed at the submucosal level spreading outside the anatomic limits of the nasopharynx. At presentation, NPC associated with hearing problems, serous otitis media, tinnitus, nasal obstruction, anosmia, bleeding, difficulty in swallowing and dysphonia, and even eye symptoms with diplopia and pain. The initial diagnosis is difficult to make because early signs and symptoms of NPC are not specific to the disease. Early-age Epstein-Barr virus (EBV) infection combined with frequent exposure to environmental carcinogenic co-factors is suggested to cause NPC development. Undifferentiated NPC is the most frequent histological type and is closely associated with EBV. Expression of the EBV-encoded latent membrane protein 1(LMP1) oncogene in biopsy material was compared between NPC patients of <30 years old and those of ≥30 years old, matched for sex and tumor stage. Higher LMP1 expression in patients of <30 years old was observed, which was related to more locoregional progressivity. Increased medical awareness of prevailing early stage signs and symptoms coupled to use of EBV-related diagnostic tumor markers may lead to down-staging and timely treatment to improve survival of patients with this aggressive disease.

Combinatorial antibody library from multiple sclerosis patients reveals antibodies that cross-react with myelin basic protein and EBV antigen

Multiple sclerosis (MS) is a widespread neurodegenerative autoimmune disease with unknown etiology. It is increasingly evident that, together with pathogenic T cells, autoreactive B cells are among the major players in MS development. The analysis of myelin neuroantigen-specific antibody repertoires and their possible cross-reactivity against environmental antigens, including viral proteins, could shed light on the mechanism of MS induction and progression. A phage display library of single-chain variable fragments (scFvs) was constructed from blood lymphocytes of patients with MS as a potential source of representative MS autoantibodies. Structural alignment of 13 clones selected toward myelin basic protein (MBP), one of the major myelin antigens, showed high homology within variable regions with cerebrospinal fluid MS-associated antibodies as well as with antibodies toward Epstein-Barr latent membrane protein 1 (LMP1). Three scFv clones showed pronounced specificity to MBP fragments 65-92 and 130-156, similar to the serum MS antibodies. One of these clones, designated E2, in both scFv and full-size human antibody constructs, was shown to react with both MBP and LMP1 proteins in vitro, suggesting natural cross-reactivity. Thus, antibodies induced against LMP1 during Epstein-Barr virus infection might act as inflammatory trigger by reacting with MBP, suggesting molecular mimicry in the mechanism of MS pathogenesis.

Multiple roles of LMP1 in Epstein-Barr virus induced immune escape

The life cycle of Epstein-Barr virus (EBV) is intriguing in that the virus resides within the immune system and utilizes distinct latency expression programs to establish a persistent infection yet escaping elimination. To achieve this EBV has hijacked cellular signaling pathways to its own benefit, but deregulated viral gene expression can turn into oncogenesis. EBV like many other persistent herpes viruses has evolved ingenious tricks to evade the immune system in part by mimicking host gene function(s). Latent membrane protein 1 (LMP1) mimics CD40 signaling as part of its "normal" biological function and when deregulated, functions as a viral oncogene. LMP1 also affects cell-cell contact, cytokine and chemokine production, Ag presentation and is secreted in the extracellular milieu via immunogenic exosomes. Thus, besides its well-known growth promoting properties LMP1 modulates immune responses. Herein we discuss current knowledge regarding the role of LMP1 in immune evasion of EBV and how this strategy for establishment of persistence contributes to immune escape of EBV+ tumors.

Native early antigen of Epstein-Barr virus, a promising antigen for diagnosis of nasopharyngeal carcinoma

The Epstein-Barr virus (EBV) early antigen (EA) complex consists of multiple proteins with relevance for diagnosis of acute, chronic and malignant EBV related diseases, including nasopharyngeal carcinoma (NPC). In a recent study, it was found that the molecular diversity of EBV-specific IgG and IgA antibody responses in NPC patients and demonstrated that these reflect independent B-cell triggering leading to distinct EBV antigen-recognition profiles. The fine-specificity of NPC-related IgG and IgA responses was explored further against defined recombinant and synthetic EBV-EA antigens using immunofluorescence, immunoblot and ELISA techniques and determined their diagnostic value in a large panel of sera from NPC (n = 154), non-NPC tumor patients (n = 133), acute mononucleosis patients (n = 70) and healthy EBV carriers (n = 259). Individual recombinant EBV-EA markers yielded sensitivity/specificity values not exceeding 86%, whereas selected EA-specific peptide epitopes were rather poorly recognized by IgG and IgA antibodies in NPC sera. Surprisingly, we found that a "low salt" native EA-protein extract reproducibly prepared from purified nuclei of EA-induced HH514 cells, and containing characteristic EA(D)-polypeptides, such as p47-54 (BMRF1), p138 (BALF2), p55-DNAse (BGLF5), and p65-TK (BXLF1), but without viral capsid (VCA) or nuclear antigen (EBNA) reactivity, gave highest sensitivity (90.4%) and specificity (95.5%) values for NPC diagnosis in both IgG and IgA ELISA. The data support further the notion that EBV-EA reactive IgG and IgA antibodies in NPC patients are directed against distinct conformational and-in part-linear epitopes on EBV-specific proteins, barely recognized in other EBV-related syndromes. The use of a defined native EBV EA-specific antigen opens the way to further improve serological diagnosis of NPC.

Epstein-Barr virus infection and risk of lymphoma: immunoblot analysis of antibody responses against EBV-related proteins in a large series of lymphoma subjects and matched controls

Epstein-Barr Virus (EBV) is consistently associated with distinct lymphoproliferative malignancies and aberrant EBV antibody patterns are found in most EBV cancer patients. We evaluate the detection of an abnormal reactive serological pattern to EBV (ab_EBV) infection and the risk of lymphoma in a multicentric case-control study. Serum samples were collected at study entry from 1,085 incident lymphoma cases from Spain, France, Germany, Czech Republic, Italy and 1,153 age, sex and country matched controls. EBV immunoglobulin G (IgG) serostatus was evaluated through a peptide-based ELISA combining immunodominant epitopes of EBNA1 (BKRF1) and VCA-p18 (BFRF3). Further, immunoblot analysis was performed to evaluate distinct antibody diversity patterns to EBV early antigens (EA), besides EBNA1, VCA-p18, VCA-p40 (BdRF1) and Zebra (BZLF1). Patients with chronic active EBV infection and aberrant EBV activity were characterized as having an abnormal reactive pattern (ab_EBV). Ab_EBV was observed in 20.9% of 2,238 included subjects with an increased proportion of cases presenting ab_EBV as compared to the control population (23.9% vs. 18.0% p = 0.001). Ab_EBV positivity was a risk factor for all lymphomas combined (odds ratio [OR] = 1.42, 95% confidence interval [CI]=1.15-1.74), and specifically for chronic lymphocytic leukaemia (OR = 2.96, 95%CI = 2.22-3.95). Lower levels of ab_EBV were observed for follicular lymphoma (OR = 0.38, 95%CI = 0.15-0.98). EBV may be involved in a larger subset of lymphomas among clinically immunocompetent subjects than previously thought, probably explained by an underlying loss of immune control of EBV latent infection. Ab_EBV is a useful tool to explore EBV imbalances preceding or paralleling possible EBV associated oncogenic events.

Aberrant Epstein-Barr virus persistence in HIV carriers is characterized by anti-Epstein-Barr virus IgA and high cellular viral loads with restricted transcription

OBJECTIVE

Epstein-Barr virus (EBV)-positive lymphomas in HIV carriers are paralleled by elevated EBV-DNA loads in the circulation. Approximately 20% of asymptomatic HIV carriers also show elevated circulating EBV-DNA loads. We aimed to characterize the nature of this EBV DNA and to determine the transcriptional phenotype of EBV in blood, in relation to serological parameters.

DESIGN

A total of 197 random asymptomatic HIV carriers, representing 2% of the Dutch HIV-positive population, were sampled for blood, peripheral blood mononuclear cells and plasma. In addition, 39 EBV-DNA carriers were sampled twice, with a 5-year interval.

METHODS

EBV-DNA loads were determined by LightCycler-based real-time polymerase chain reaction (PCR). EBV transcription was studied by nucleic acid sequence-based amplification and reverse transcriptase PCR. IgA and IgG antibodies to EBV antigens EBNA1 and VCA-p18 were quantified by synthetic peptide-based enzyme-linked immunosorbent assay.

RESULTS

: Elevated EBV-DNA loads were found in whole blood of 19.3% of the tested HIV population, which were persistent in 82%. Plasma samples were EBV-DNA negative and circulating EBV DNA could be attributed to the B-cell compartment. Transcription of only LMP2 and (non-translated) transcripts from the BamHI-A region of the EBV genome was found, whereas EBNA1, LMP1 and lytic EBV transcripts were absent despite high cellular EBV-DNA loads. IgA-reactivity to VCA-p18 was seen in 69%. IgG to VCA-p18 was significantly higher in high EBV-DNA load carriers.

CONCLUSION

Asymptomatic HIV carriers show aberrant EBV persistence in the circulation, characterized by elevated, B-cell-associated EBV-DNA loads. EBV transcription is restricted, arguing for EBV gene shutdown in circulating EBV-carrying B cells. Increased IgA and IgG reactive to VCA-p18 is indicative of increased lytic EBV replication, possibly occurring at mucosal lymphoid sites but not in the circulation.

Serum antibody response to lytic and latent Epstein-Barr virus antigens in undifferentiated nasopharyngeal carcinoma patients from an area of nonendemicity

Epstein-Barr virus (EBV)-associated undifferentiated carcinoma of the nasopharyngeal type (UCNT) is highly prevalent in southeast China, where immunoglobulin A (IgA) antibodies to viral capsid antigen and early antigen (EA) represent important markers, routinely used to assist in diagnosing this malignancy. Our study aimed at determining the EBV serological profiles of 78 UCNT patients from Italy, an area of nonendemicity for this tumor, using different assays specific for both lytic and latent EBV antigens. Serum IgA against both EA and EBNA1 and IgG and IgA to the latent membrane protein 1 (LMP1), to EA, and to the EBV transactivator ZEBRA protein were assessed. These serological responses were then evaluated according to the clinicopathologic parameters at diagnosis. The sensitivities of the IgG assays were 37.7% for LMP1, 73.6% for EA, and 61.0% for ZEBRA. EA/EBNA1 IgA reactivity was 84.4%, and a high association (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.7 to 4.0) with UCNT was observed. When EBV serological reactivities were analyzed according to the tumor, node, and metastasis staging system (TNM), a statistically significant association was found between N stage and IgG antibody rates for EA (OR, 3.6; 95% CI, 1.2 to 10.9) and ZEBRA (OR, 2.6; 95% CI, 1.2 to 5.5) and between M stage and IgG antibody rates for ZEBRA (OR, 7.1; 95% CI, 3.2 to 16.0) and LMP1 (OR, 14.0; 95% CI, 1.8 to 110.9). Our results show that no single serological marker allows the detection of all UCNT cases. EA/EBNA1 IgA represents a reliable marker for diagnosis, with a high predictive value also in areas where UCNT is not endemic, such as Italy. The analysis of serological results according to TNM classification is consistent with a progressive impairment of humoral immune response to EBV as the disease advances and may be used to improve the accuracy of diagnosis.

Epstein-Barr virus (EBV) serology for predicting distant metastases in a white juvenile patient with nasopharyngeal carcinoma and no clinical response to EBV lytic induction therapy

BACKGROUND

We describe a case of a 16-year-old white girl with Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC). METHODS.: At diagnosis, the patient had characteristic immunoglobulin (Ig)A and IgG responses to EBNA1, viral capsid antigen (VCA)-p18, and early antigens (EAs), with no detectable EBV DNA in her blood. Combined chemotherapy and radiotherapy resulted in complete remission. Eighteen months later, the patient's IgA responses to EBNA1 and p18 and both IgA and IgG anti-EA increased, without apparent recurrence. Five months later, lung metastases were found. She underwent surgical removal of the lung metastases and conventional chemotherapy, but had intraabdominal lymph node metastasis and mediastinal lesions develop. The patient was then treated with a novel treatment consisting of 5-fluorouracil plus valproic acid and subsequent valganciclovir to induce lytic EBV replication. This resulted in the first detectable EBV DNA levels in the blood but did not result in clinical response.

RESULTS

The patient's disease progressed, and the patient declined further cancer treatment and died.

CONCLUSION

In contrast to EBV DNA load, EBV serology was useful in predicting distant NPC metastasis after initial complete remission in this patient.

Role of sexual behavior in the acquisition of asymptomatic Epstein-Barr virus infection: a longitudinal study

BACKGROUND

The natural history of Epstein-Barr virus (EBV) infection is poorly defined. We report the prevalence and subsequent incidence of EBV infection in a cohort of sexually active young women and explore the social and sexual determinants of incident infections.

METHODS

The study population was drawn from a cohort of young women, who were recruited for a longitudinal study of risk factors for early cervical neoplasia. A case-control analysis, nested within the cohort of 45 women for whom the first EBV sample tested was EBV-negative and who had further follow-up, was undertaken. EBV serostatus was determined in serum with a synthetic peptide-based enzyme-linked immunosorbent assay; EBV DNA was measured in cervical smears with the use of quantitative polymerase chain reaction.

RESULTS

Of 1023 women 15-19 years of age included in this analysis, 978 (95.6%) tested positive for antibodies to EBV in their first serum sample. Of 45 women who tested negative, 22 subsequently acquired an asymptomatic EBV infection; the median time to seroconversion was 25 months (range, 1-60 months), and the median age at seroconversion was 18 years (range, 16-21 years). The risk of seroconversion increased with increasing number of sexual partners [compared with 1 partner, odds ratio (OR) was 1.28 for 2 partners and 2.23 for 3 or more; chiTREND 5.02; df 1; P < 0.05] and was greatest when a new sexual partner had been acquired in the 2 years before seroconversion (OR 4.78; chi 4.62; df 1; P < 0.05). EBV DNA was detected in 9 of 14 women who seroconverted and who also provided cervical samples.

CONCLUSIONS

In susceptible young women, the acquisition of EBV infection is associated with their sexual behavior.

Comparison of three different serological techniques for primary diagnosis and monitoring of nasopharyngeal carcinoma in two age groups from Tunisia

Nasopharyngeal carcinoma (NPC) in Tunisia is characterized by its bimodal age distribution involving juvenile patients of 10-24 years and adult patients of 40-60 years. Three serological techniques were compared for primary diagnosis (N = 117) and post-treatment monitoring (N = 21) of NPC patients separated in two age groups. Immunofluorescence assay (IFA) was used as the "gold standard" for detection of IgG and IgA antibodies reactive with Epstein-Barr virus (EBV) early (EA) and viral capsid (VCA) antigens. Results were compared with ELISA measuring IgG and IgA antibody reactivity to defined EBNA1, EA, and VCA antigens. Immunoblot was used to reveal the molecular diversity underlying the anti-EBV IgG and IgA antibody responses. The results indicate that young NPC patients have significantly more restricted anti-EBV IgG and IgA antibody responses with aberrant IgG VCA/EA levels in 78% compared to 91.7% in elder patients. IgA VCA/EA was detected in 50% of young patients versus 89.4% for the elder group (P < 0.001). Immunoblot revealed a reduced overall diversity of EBV antigen recognition for both IgG and IgA in young patients. A good concordance was observed between ELISA and IFA for primary NPC diagnosis with 81-91% overall agreement. Even better agreement (95-100%) was found for antibody changes during follow-up monitoring, showing declining reactivity in patients in remission and increasing reactivity in patients with persistent disease or relapse. ELISA for IgA anti-VCA-p18 and immunoblot proved most sensitive for predicting tumor relapse. VCA-p18 IgA ELISA seems suitable for routine diagnosis and early detection of NPC complication.

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.