Novel immunoblot assay using four recombinant antigens for diagnosis of Epstein-Barr virus primary infection and reactivation

Early screening of nasopharyngeal carcinoma

The low positive predictive value (PPV) of early screening of nasopharyngeal carcinoma (NPC) is the problems that need to be solved urgently. The combination of cell-free DNA (cfDNA) methylation testing and Epstein-Barr virus (EBV) serological testing is the key to solve this problem. This paper reviews recent advances in early screening for NPC and cfDNA methylation, with future perspectives. Pubmed was searched for the literature related to early screening of NPC and cfDNA methylation in the past 5 years. The results of these studies were summarized. Despite these efforts, the PPV is still low (10%). Previous studies have shown that cfDNA methylation analysis has good specificity and accuracy across a variety of tumors. The combination of cfDNA methylation and EBV detection helps to improve the PPV for early screening of NPC. The combination of cfDNA methylation and EBV serological testing is key to addressing the low PPV of NPC early screening.

Prospective evaluation of blood Epstein-Barr virus DNA load and antibody profile in HIV-related non-Hodgkin lymphomas

OBJECTIVES

The value of Epstein-Barr virus (EBV) biomarkers on the prognosis of HIV-related non-Hodgkin's lymphoma (NHL) has been poorly explored in the combined antiretroviral therapy (cART) era.

DESIGN

We evaluated EBV DNA load and EBV antibodies in HIV-NHL patients enrolled in the French ANRS-CO16 Lymphovir Cohort between 2008 and 2015.

METHODS

Whole blood and plasma EBV DNA load and serological profiles were analyzed in 76 HIV-infected patients at diagnosis of NHL and 6 months after the initiation of chemotherapy.

RESULTS

Prechemotherapy whole blood (WB) and plasma EBV DNA loads were positive for 80 and 45% of HIV-NHL patients, respectively. Pretreatment WB EBV DNA positivity was associated with a positive plasma HIV-1 RNA load (relative risk (RR), 4.42 [1.33; 14.72]) and plasma EBV DNA positivity with EBV in situ detection (RR 10.62 [2.38; 47.49]). Following chemotherapy, the proportions of patients with positive WB or plasma EBV DNA declined from 81 to 23% (P < 0.0001) and from 43 to 8% (P < 0.0001), respectively. Estimated 2-year progression-free survival did not differ according to prechemotherapy WB positivity (82% versus 67%, P = 0.15) or plasma EBV DNA positivity (76% versus 81%, P  = 0.52).

CONCLUSIONS

The plasma EBV DNA load correlates with in situ EBV detection. The WB EBV DNA load correlates with HIV load. WB and plasma EBV DNA loads at NHL diagnosis do not constitute prognostic markers for HIV-NHL patients in the modern cART era.

Anti-N-methyl-D-aspartate receptor encephalitis associated with reactivated Epstein-Barr virus infection in pediatric patients: Three case reports

RATIONALE

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most frequent autoimmune encephalitis in children, and its presentation is various. The disease can be triggered by various infections.

PATIENT CONCERNS

Case 1 was a 7-year-old female with the presentation of seizure, repeated fever, language disorder, and decreased muscle strength of the right limbs; Case 2 was a 7-year-old male with the manifestation of repeated emesis, headache, involuntary movement, altered personality, seizures, and cognitive impairment; Case 3 was a 2-year-old female with repeated fever, emesis, seizures, coma, and decreased muscle strength of limbs. Anti-NMDAR antibody was identified in cerebrospinal fluid (CSF) in the 3 cases, confirming the diagnosis of anti-NMDAR encephalitis. Pathogenic examinations revealed positive serum Epstein-Barr virus (EBV)-nuclear antigen and EBV-capsid antigen (CA)-IgG antibodies in the 3 cases, as well as positive EBV-early antigen (EA)-IgG antibody in CSF. Case 1 also had positive EBV-CA-IgA antibody; Case 3 also had positive EBV-CA-IgA and EBV-CA-IgG antibodies.

DIAGNOSES

Anti-NMDAR antibody and EBV-EA-IgG antibody in CSF were tested positive in the 3 cases. Thus, they were diagnosed as anti-NMDAR encephalitis associated with reactivated EBV infection.

INTERVENTIONS

All of the 3 cases received immunoglobulin, corticosteroid, and ganciclovir treatment. Cases 2 and 3 also received antiepileptic drugs due to repeated seizures. In addition, Case 3 also received assistant respiration, plasma exchange, and rituximab.

OUTCOMES

The 3 cases were substantially recovered after treatment. Repeat CSF analysis showed decreased titer of the anti-NMDAR antibody.

LESSONS

Reactivated EBV infection may trigger anti-NMDAR encephalitis in children, which has not been reported previously. Related possible virology tests should be completed while diagnosing the disease.

Epstein-Barr virus biomarkers have no prognostic value in HIV-related Hodgkin lymphoma in the modern combined antiretroviral therapy era

OBJECTIVES

Epstein-Barr virus (EBV) has been implicated in lymphomagenesis of HIV-related classical Hodgkin lymphoma (HIV-cHL). The utility of EBV molecular and serological biomarkers has scarcely been examined in HIV-cHL in the recent combined antiretroviral therapy (cART) era.

DESIGN

We evaluated EBV DNA load and a panel of EBV antibodies in HIV-cHL patients prospectively enrolled in the French ANRS-CO16 Lymphovir cohort between 2008 and 2015.

METHODS

Pretreatment whole blood, plasma EBV DNA load and serological profiles were analysed in 63 HIV-infected patients diagnosed with cHL. For the 42 patients with available material, comparisons were performed between values at diagnosis and 6 months after the initiation of chemotherapy.

RESULTS

Pretreatment whole blood and plasma EBV DNA loads were positive in 84 and 59% of HIV-cHL patients, respectively. Two-year progression-free survival estimates did not differ between the patients with pretreatment whole blood (n = 53) or plasma (n = 37) EBV DNA(+) and the patients with pretreatment whole blood (n = 10) or plasma (n = 26) EBV DNA(-) (92 vs. 80% or 89 vs. 92%, P = 0.36 and 0.47, respectively). At diagnosis, 47% of patients harboured an EBV reactivation serological profile. Following chemotherapy, whole blood and plasma EBV DNA levels significantly declined from medians of 1570 [interquartile range, 230-3760) and 73 (0-320) copies/ml to 690 (0-1830) and 0 (0-0) copies/ml, respectively (P = 0.02 and P < 0.0001, respectively]. Anti-EBV IgG antibody level significantly dropped at 6-month follow-up (P = 0.004).

CONCLUSION

Whole blood and plasma EBV DNA loads do not constitute prognostic markers in HIV-cHL patients in the modern cART era.

Lytic EBV infection investigated by detection of Soluble Epstein-Barr virus ZEBRA in the serum of patients with PTLD

The ZEBRA protein (encoded by the BZLF1 gene), is the major transcription factor of EBV, expressed upon EBV lytic cycle activation. Several studies highlighted the critical role of EBV lytic infection as a risk factor for lymphoproliferative disorders like post-transplant lymphoproliferative disease (PTLD). Here, we use an antigen-capture ELISA assay specifically designed to detecting the circulating soluble ZEBRA (sZEBRA) in serum samples (threshold value determined at 40ng/mL). We retrospectively investigated a population of 66 transplanted patients comprising 35 PTLD. All the samples from a control population (30 EBV-seronegative subjects and 25 immunocompetent individuals with EBV serological reactivation), classified as sZEBRA < 40ng/mL were assigned as negative. At PTLD diagnosis, EBV genome (quantified by qPCR with EBV DNA>200 copies/mL) and sZEBRA were detectable in 51% and 60% of cases, respectively. In the patients who developed a pathologically-confirmed PTLD, the mean sZEBRA value in cases, was 399 ng/mL +/− 141 versus 53ng/mL +/− 7 in patients who did not (p  < 0,001). This is the first report relating to the detection of the circulating ZEBRA in serum specimens, as well as the first analysis dealing with the lytic cycle of EBV in PTLD patients with this new biomarker.

Multiparametric Detection of Antibodies against Different EBV Antigens to Predict Risk for Nasopharyngeal Carcinoma in a High-Risk Population of China

In this study, we aimed to use the combined detection of multiple antibodies against Epstein-Barr virus (EBV) antigens to develop a model for screening and diagnosis of nasopharyngeal carcinoma (NPC). Samples of 300 nasopharyngeal carcinoma patients and 494 controls, including 294 healthy subjects (HC), 99 non-nasopharyngeal carcinoma cancer patients (NNPC), and 101 patients with benign nasopharyngeal lesions (BNL), were incubated with the EUROLINE Anti-EBV Profile 2, and band intensities were used to establish a risk prediction model. The nasopharyngeal carcinoma risk probability analysis based on the panel of VCAgp125 IgA, EBNA-1 IgA, EA-D IgA, EBNA-1 IgG, EAD IgG, and VCAp19 IgG displayed the best performance. When using 26.1% as the cutoff point in ROC analysis, the AUC value and sensitivity/specificity were 0.951 and 90.7%/86.2%, respectively, in nasopharyngeal carcinoma and all controls. In nasopharyngeal carcinoma and controls without the non-nasopharyngeal carcinoma and BNL groups, the AUC value and sensitivity/specificity were 0.957 and 90.7%/88.1%, respectively. The diagnostic specificity and sensitivity of the EUROLINE Anti-EBV Profile 2 assay for both nasopharyngeal carcinoma and early-stage nasopharyngeal carcinoma were higher than that of mono-antibody detection by immune-enzymatic assay and real-time PCR (EBV DNA). In the VCA-IgA-negative group, 82.6% of nasopharyngeal carcinoma patients showed high probability for nasopharyngeal carcinoma, and the negative predictive value was 97.1%. In the VCA-IgA-positive group, 73.3% of healthy subjects showed low probability. The positive predictive value reached 98.2% in this group. The nasopharyngeal carcinoma risk probability value determined by the EUROLINE Anti-EBV Profile 2 might be a suitable tool for nasopharyngeal carcinoma screening. Cancer Prev Res; 10(9); 542-50. ©2017 AACR.

EA-D p45-IgG as a potential biomarker for nasopharyngeal carcinoma diagnosis

AIM

To identify new biomarkers for NPC diagnosis with an anti-EBV Western blot test kit.

METHODS

Serum samples from 64 NPC patients and healthy subjects with four specific VCA-IgA/EA-IgA profiles were tested with an anti-EBV Western blot test kit from EUROIMMUN AG. Proteins were quantified with scores of intensity visually assigned to the protein bands. The markers which showed statistical differences between the NPC and non-NPC subjects were further evaluated in another 32 NPC patients and 32 controls in comparison with established biomarkers including VCA-IgA, EA-IgA, EBV-related protein IgG, and EBV DNA.

RESULTS

Among the markers screened, EA-D p45-IgG showed a statistically significant difference (p < 0.05) between NPC and non-NPC subjects with VCA-IgA positivy. In 32 VCA-IgA positive NPC patients and 32 control subjects, the diagnostic accuracy of EA-D p45-IgG was 78.1% with a positive predictive value of 77.8% and a negative predictive value of 78.6%. In the verification experiment, the specificity and sensitivity of EA-D p45-IgG were 75.0% and 90.6 %, respectively.

CONCLUSIONS

EA-D p45-IgG might be a potential biomarker for NPC diagnosis, especially among VCA-IgA positive subjects.

Is there diagnostic value in detection of immunoglobulin g antibodies to the epstein-barr virus early antigen?

The Epstein-Barr virus early antigen (EBV EA) complex consists of multiple proteins with potential significance for diagnosis of EBV-related diseases. In many individuals, detection of antibody to the early antigen (EA) is a sign of active infection, but 20% of healthy people may have this antibody for years. We studied the role of EA immunoglobulin G (IgG) in individuals with atypical antibody responses in the diagnosis of infectious mononucleosis (IM) and in EBV-infected transplant patients. EA IgG was present in 72% of confirmed IM patients. A trend was observed between high viral loads and the presence of EA IgG and between low viral loads and the absence of EA IgG in EBV-associated disease negative liver transplant recipients. Three assays that measure serum EA IgG were compared; enzyme-linked immunosorbent assay (ELISA), chemiluminescent immunoassay (CLIA), and immunoblot assay. The automated CLIA was found to be more accurate than the ELISA when using the immunoblot assay as a "gold standard" assay in the detection of EA IgG. There may be a potential role for EA IgG testing, together with EBV viral load, in the prediction of transplant recipients at risk of EBV-associated disease; however, EA IgG does not play a significant role in the differential diagnosis of EBV infection in immunocompetent individuals.

An automated ELISA using recombinant antigens for serologic diagnosis of B virus infections in macaques

B virus (Macacine herpesvirus 1) occurs naturally in macaques and can cause lethal zoonotic infections in humans. Detection of B virus (BV) antibodies in macaques is essential for the development of SPF breeding colonies and for diagnosing infection in macaques that are involved in human exposures. Traditionally, BV infections are monitored for presence of antibodies by ELISA (a screening assay) and western blot analysis (WBA; a confirmatory test). Both tests use lysates of infected cells as antigens. Because WBA often fails to confirm the presence of low-titer serum antibodies detected by ELISA, we examined a recombinant-based ELISA as a potential alternative confirmatory test. We compared a high-throughput ELISA using 384-well plates for simultaneous antibody screening against 4 BV-related, recombinant proteins with the standard ELISA and WBA. The recombinant ELISA results confirmed more ELISA-positive sera than did WBA. The superiority of the recombinant ELISA over WBA was particularly prominent for sera with low (<500 ELISA units) antibody titers. Among low-titer sera, the relative sensitivity of the recombinant ELISA ranged from 36.7% to 45.0% as compared with 3.3% to 10.0% for WBA. In addition, the screening and confirmatory assays can be run simultaneously, providing results more rapidly. We conclude that the recombinant ELISA is an effective replacement for WBA as a confirmatory assay for the evaluation of macaque serum antibodies to BV.

Performance of two commercially available automated immunoassays for the determination of Epstein-Barr virus serological status

This study evaluated the performance of two automated Vidas (V) and Liaison (L) immunoassays for Epstein-Barr virus (EBV) serology. The detection of the viral capsid antigen (VCA) IgM, the VCA/early antigen (VCA/EA) IgG, and the Epstein-Barr nuclear antigen (EBNA) IgG was assessed on 526 sera collected for routine EBV testing in immunocompetent subjects. The determination of expected EBV status (186 EBV primary infections, 183 past EBV infections, and 157 EBV-seronegative individuals) was based on results of routine laboratory enzyme immunoassays (EIAs) together with clinical data. The sensitivity and specificity of each individual marker were determined in comparison to the expected EBV status. The agreement between the V and L profiles and the expected EBV status was established through the interpretation of combinations of the different EBV markers. Statistically significant differences between the two tests were found for the specificity of the VCA IgM marker (96.2% for V versus 93.2% for L), the sensitivity of the VCA/EA IgG marker (89% for V versus 94% for L), and the specificity of the EBNA IgG marker (96.5% for V versus 74.2% for L). The results determined for the two assays with respect to overall agreement with the established expected EBV status were not significantly different (89.7% for V versus 88.2% for L), with discrepancies mainly observed in sera referenced as primary infections. These findings demonstrated the similar performances of the Vidas and the Liaison assays for the establishment of an EBV serological status using the VCA, EA, and EBNA markers.

Epstein-Barr virus neutralizing and early antigen antibodies in multiple sclerosis

BACKGROUND

Our objective was to determine whether antibodies against the Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA-1), early antigen (EA), and EBV neutralizing antibodies (NeutAb) are altered in multiple sclerosis (MS).

METHODS

We measured EBNA-1 IgG, EA IgG, and EA IgA using quantitative ELISA. We measured NeutAb using a quantitative competitive ELISA. We studied 80 patients with MS, 80 matched controls, and 19 patients with MS with samples collected both whilst stable and in relapse.

RESULTS

Epstein-Barr virus nuclear antigen-1 IgG and EA IgA were increased in MS compared to controls. The EBNA-1 index value was 23.3 ± 18.3 in the patients with MS (mean ± SD) and 16.3 ± 17.4 in the controls (P = 0.007, paired t-test). EA IgA had a median value of 1.964 in the patients with MS and 1.248 in the controls (P = 0.029, Wilcoxon signed rank test). EA IgG and NeutAb were not significantly different. None of the antibody levels were altered in relapse. The correlation between concentrations of different antibodies was minimal.

CONCLUSIONS

IgG antibodies to EBNA-1 are significantly increased in MS. IgA antibodies against EBV EA are also increased. The EBV neutralizing antibody response is similar in MS and controls.

Intrathecal immune responses to EBV in early MS

EBV has been consistently associated with MS, but its signature in the CNS has rarely been examined. In this study, we assessed EBV-specific humoral and cellular immune responses in the cerebrospinal fluid (CSF) of patients with early MS, other inflammatory neurological diseases (OIND) and non-inflammatory neurological diseases (NIND). The neurotropic herpesvirus CMV served as a control. Virus-specific humoral immune responses were assessed in 123 consecutive patients and the intrathecal recruitment of virus-specific antibodies was expressed as antibody indexes. Cellular immune responses tested in the blood of 55/123 patients were positive in 46/55. The CD8(+) CTL responses of these 46 patients were assessed in the blood and CSF using a CFSE-based CTL assay. We found that viral capsid antigen and EBV-encoded nuclear antigen-1, but not CMV IgG antibody indexes, were increased in early MS as compared with OIND and NIND patients. There was also intrathecal enrichment in EBV-, but not CMV-specific, CD8(+) CTL in early MS patients. By contrast, OIND and NIND patients did not recruit EBV- nor CMV-specific CD8(+) CTL in the CSF. Our data, showing a high EBV-, but not CMV-specific intrathecal immune response, strengthen the association between EBV and MS, in particular at the onset of the disease.

Strong EBV-specific CD8+ T-cell response in patients with early multiple sclerosis

Epstein-Barr virus (EBV) has been associated with multiple sclerosis (MS), however, most studies examining the relationship between the virus and the disease have been based on serologies, and if EBV is linked to MS, CD8+ T cells are likely to be involved as they are important both in MS pathogenesis and in controlling viruses. We hypothesized that valuable information on the link between MS and EBV would be ascertained from the study of frequency and activation levels of EBV-specific CD8+ T cells in different categories of MS patients and control subjects. We investigated EBV-specific cellular immune responses using proliferation and enzyme linked immunospot assays, and humoral immune responses by analysis of anti-EBV antibodies, in a cohort of 164 subjects, including 108 patients with different stages of MS, 35 with other neurological diseases and 21 healthy control subjects. Additionally, the cohort were all tested against cytomegalovirus (CMV), another neurotropic herpes virus not convincingly associated with MS, nor thought to be deleterious to the disease. We corrected all data for age using linear regression analysis over the total cohorts of EBV- and CMV-infected subjects. In the whole cohort, the rate of EBV and CMV infections were 99% and 51%, respectively. The frequency of IFN-gamma secreting EBV-specific CD8+ T cells in patients with clinically isolated syndrome (CIS) was significantly higher than that found in patients with relapsing-remitting MS (RR-MS), secondary-progressive MS, primary-progressive MS, patients with other neurological diseases and healthy controls. The shorter the interval between MS onset and our assays, the more intense was the EBV-specific CD8+ T-cell response. Confirming the above results, we found that EBV-specific CD8+ T-cell responses decreased in 12/13 patients with CIS followed prospectively for 1.0 +/- 0.2 years. In contrast, there was no difference between categories for EBV-specific CD4+ T cell, or for CMV-specific CD4+ and CD8+ T-cell responses. Anti-EBV-encoded nuclear antigen-1 (EBNA-1)-specific antibodies correlated with EBV-specific CD8+ T cells in patients with CIS and RR-MS. However, whereas EBV-specific CD8+ T cells were increased the most in early MS, EBNA-1-specific antibodies were increased in early as well as in progressive forms of MS. Our data show high levels of CD8+ T-cell activation against EBV--but not CMV--early in the course of MS, which support the hypothesis that EBV might be associated with the onset of this disease.

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.

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.

Epstein-Barr virus and disease activity in multiple sclerosis

OBJECTIVES

To study in relapsing-remitting (RR) multiple sclerosis (MS) whether exacerbations and brain activity as measured by magnetic resonance imaging (MRI) are associated with plasma levels of anti-Epstein Barr (EBV) antibodies and EBV DNA.

METHODS

This was a prospective study with 73 RR MS patients followed for an average of 1.7 years with frequent neurological examination and blood sampling. Antibodies to various EBV proteins were measured by ELISA and plasma EBV DNA was measured by PCR.

RESULTS

All MS patients had IgG antibodies to EBV (viral capsid antigen (VCA) and/or EBV nuclear antigen (EBNA)), irrespective whether samples were taken at stable disease or exacerbation. A significantly elevated percentage of the patients (48%) had antibodies against EBV antigens (early antigen, EA) that indicate active viral replication, compared with the age matched healthy controls (25%). Antibodies against a control herpesvirus, cytomegalovirus, were similar between the two groups. The percentage of EA positive individuals and EA titres did not differ between stable disease or exacerbation. Anti-VCA IgM was positive in three cases, unrelated to disease activity. Using a highly sensitive PCR on 51 samples taken at exacerbation visits, only three patients were found to have one timepoint with viraemia, and this viraemia was unrelated to disease activity. Of special note was the fact that anti-EA seropositive patients remained seropositive during follow up, with stable titres over time. We hypothesised that these patients may constitute a subgroup with higher disease activity, due to the triggering effect of a chronic attempt of the virus to reactivate. The EA positive group did not differ from the EA negative with respect to clinical disease activity or other characteristics. However, in the EA positive group, analysis with gadolinium enhanced MRI indicated more MRI disease activity.

CONCLUSIONS

There was no evidence for increased clinical disease activity in the subgroup of MS patients with serological signs of EBV reactivation. However, the observation that chronic EBV reactivation may be associated with increased inflammatory activity as assessed by gadolinium enhanced MRI lesions should be reproduced in a larger and independent dataset.

Improvement of Lyme borreliosis serodiagnosis by a newly developed recombinant immunoglobulin G (IgG) and IgM line immunoblot assay and addition of VlsE and DbpA homologues

We developed and evaluated a recombinant Borrelia line immunoblot assay based on 18 homologues of seven different antigens, i.e., p100, p58, p41i, BmpA, VlsE, OspC, and DbpA. Each recombinant antigen can be detected separately and is distinct even from homologues with identical molecular weights. This blot was compared to the recently described recombinant Borrelia Western immunoblot assay (U. Schulte-Spechtel, G. Lehnert, G. Liegl, V. Fingerle, C. Heimerl, B. J. Johnson, and B. Wilske, J. Clin. Microbiol. 41:1299-1303, 2003). To verify sensitivity and specificity, both blots were evaluated for reactivity with Borrelia-specific immunoglobulin G (IgG) and IgM antibodies with 85 sera from patients with different manifestations of Lyme borreliosis and 110 controls. According to European interpretation criteria for Borrelia Western blots, which define a serum as positive when it recognizes at least two bands, sensitivity increased significantly from 70.6% (Western blot) to 84.7% (line blot) for IgG (P = 0.042) and from 40.0% (Western blot) to 73.8% (line blot) for IgM (P < 0.005). The increased sensitivity for IgG detection is due to the new line blot technique, whereas the improvement in detection of IgM is mainly achieved through incorporation of the additional antigens. Notably, the recombinant VlsE of Borrelia garinii strain PBi displayed the highest sensitivity of all antigens tested for IgG detection and is also one of the most useful antigens for IgM. Due to its excellent sensitivity and specificity combined with ease of evaluation, this line immunoblot assay offers a useful improvement in serodiagnosis of Lyme borreliosis.

Human herpesvirus 8--a novel human pathogen

In 1994, Chang and Moore reported on the latest of the gammaherpesviruses to infect humans, human herpesvirus 8 (HHV-8) [1]. This novel herpesvirus has and continues to present challenges to define its scope of involvement in human disease. In this review, aspects of HHV-8 infection are discussed, such as, the human immune response, viral pathogenesis and transmission, viral disease entities, and the virus's epidemiology with an emphasis on HHV-8 diagnostics.

Evaluation of four commercially available Epstein-Barr virus enzyme immunoassays with an immunofluorescence assay as the reference method

Four commercially available enzyme immunoassays (EIAs) (Novitec, Biotest, Virotech, and DiaSorin) were evaluated, with an indirect immunofluorescence assay as the reference method, for Epstein-Barr virus (EBV) VCA (viral capsid antigen) immunoglobulin G (IgG), VCA IgM, or EBNA (EBV nuclear antigen) IgG at three different locations (Homburg, Stuttgart, and Dresden). Serum samples from 66 immunocompetent patients with infectious mononucleosis, 73 patients without prior EBV infection, and 96 patients with past EBV infections and 29 serum samples with possible cross-reactions to other herpesviruses were included. In addition, 25 samples from an extensively pretested panel that is commercially available (Boston Biomedica) were tested. Each sample was tested at only one location. The four EIAs varied considerably in performance. When analyzing for EBV diagnosis, the Novitec assay performed the best, with 4.9% discrepant diagnoses, followed by the Biotest, Virotech, and DiaSorin assays, with 6.8, 11.7, and 14.0% discrepant diagnoses, respectively. On the basis of single-parameter analysis, the Novitec assay also showed the lowest number of discrepant results, with 3.5%, compared with the Virotech, Biotest, and DiaSorin assays, which produced 5.4, 6.4, and 8.6% discrepant results, respectively. VCA assays using affinity-purified native antigens performed better than assays with recombinant or synthetic antigens. The synthetic EBNA-1s showed the lowest concordance with the reference compared to recombinant p72. Commercially available EBV EIAs differed considerably in performance; however, some proved to be reliable and convenient alternatives to the indirect immunofluorescence assay for routine diagnostics. Native antigens, rather than synthetic peptides, are favored for EBV serology testing.

Dynamics of Epstein-Barr virus in HIV-1-infected subjects on highly active antiretroviral therapy

OBJECTIVE

Patients infected with HIV-1 are at high risk of developing Epstein-Barr virus (EBV)-associated lymphoproliferative disorders. This study evaluated the impact of highly active antiretroviral therapy (HAART) on EBV infection.

METHODS

To measure EBV content in peripheral blood lymphocytes (PBL) and in plasma, we set up a quantitative analysis using the real-time PCR. EBV latent membrane protein 1 (LMP1) expression was determined by reverse transcriptase-PCR.

RESULTS

EBV levels were determined in 33 HIV-1- and EBV-coinfected patients at the start of HAART, and during therapy. At baseline, EBV content in PBL samples ranged from 8 to 14 532 copies/microg DNA. EBV levels transiently increased in nine out of 17 patients in whom HIV-1 plasmaviraemia declined to undetectable levels (virological response) and CD4 cell counts increased (immunological response), while they remained fairly stable or decreased in the other eight virological and immunological responders, and in seven patients who showed a virological response only. Of interest, a significant increase in EBV load was observed in five out of nine patients who showed an increase in CD4 cell counts but lack of HIV-1 suppression during HAART. This EBV increase was accompanied by the detection of both LMP1 transcripts in PBL and EBV DNA in plasma, and was paralleled by an increase in immunoglobulin levels, a marker of B-cell stimulation.

CONCLUSIONS

These findings suggest that peripheral immune reconstitution during HAART without a reduction in HIV-1 replication may increase B-cell stimulation and the number of EBV-infected B cells.

Coupled particle light scattering: a new technique for serodiagnosis of Epstein-Barr virus infection

The Coupled Particle Light Scattering technique was evaluated for serological diagnosis of Epstein-Barr Virus (EBV) infection. Two hundred ninety-six patient sera selected from several clinical categories (acute infection, non-primary infection, interfering non-EBV infection, non-infected) were tested for IgM and IgG antibodies (anti-VCA, anti-EBNA and anti-EA). Determination of EBV IgG with Copalis multiplex was accurate when compared with Enzygnost Anti-EBV/IgG ELISA. Although the sensitivity of Copalis IgM for acute infections was 100% a positive IgM result did not always indicate an acute infection. Strong reactivity to IgG EA (ratio 3, 1) and IgG VCA (ratio 13, 3) correlated with persistent infection or reactivation. The CopalisI has many advantages over the existing methods, such as the possibility to measure three semi-quantitative IgG responses to three different EBV antigens simultaneously.

Evaluation of a recombinant line blot for diagnosis of Epstein-Barr Virus compared with ELISA, using immunofluorescence as reference method

A commercial line blot using recombinant antigens was compared with a commercial ELISA and 'in-house' IFA (reference test). Two panels were evaluated: Panel A was selected to distinguish between primary infections (89), past infections (20) and seronegatives (8) in immunocompetent individuals. In panel B, patients with a high number of reactivations were included: immunosuppressed patients (37), lymphoma (19), nasopharyngeal carcinoma (10), chronic fatigue syndrome (14). Blood donors (43) and cross-reactive sera (29) were added as controls. Line blot and IFA were concordant in 94% of primary infections, 100% of seronegatives and 100% of past infections, similar to ELISA. Results differed significantly with regard to reactivations. When compared with IFA, the incidence of reactivations was overestimated by the blot, 24 and 58% in blood donors and cross-reactive sera, respectively. ELISA showed a similar problems with 21 and 34% indeterminate results, respectively. The line blot is easy to carry out, has a good concordance with the reference IFA for primary infections, and is, therefore, a sufficient choice for distinguishing primary infection from seronegative and past infection. EBV reactivation assessment will require other methods such as EBV viral load.