Evaluation of four commercial systems for the diagnosis of Epstein-Barr virus primary infections. Clin Vaccine Immunol. 2011;18:444-448. [PMID: 21191077 DOI: 10.1128/cvi.00486-10]

Evaluating the Clinical Utility of Epstein-Barr Virus Antibodies as Biomarkers in Multiple Sclerosis: A Systematic Review

BACKGROUND

EBV is a necessary but not sufficient factor in the pathophysiology of multiple sclerosis (MS). EBV antibodies to the nuclear antigen (EBNA1) and viral capsid antigen (VCA) rise rapidly prior to MS disease manifestations, and their absence has clinical utility with a high negative predictive value. It remains unclear whether EBV levels act as prognostic, monitoring, or pharmacodynamic/response biomarkers. Substantial literature on this topic exists but has not been systematically reviewed. We hypothesized that EBV levels against EBNA1 and VCA are potential prognostic and monitoring biomarkers in MS, and that patient population, MS clinical phenotype, and EBV assay method may play important roles in explaining variation among study outcomes.

METHODS

We systematically searched PubMed and EMBASE from inception to April 1, 2022. After removal of duplicates, records were screened by abstract. Remaining full-text articles were reviewed. Clinical and MRI data were extracted from full-text articles for comparison and synthesis.

RESULTS

Searches yielded 696 unique results; 285 were reviewed in full, and 36 met criteria for data extraction. Heterogeneity in sample population, clinical outcome measures, assay methods and statistical analyses precluded a meta-analysis. EBV levels were not consistently associated with clinical disease markers including conversion from CIS to RRMS, neurological disability, or disease phenotype. Studies using repeated-measures design suggest that EBNA1 levels may temporarily reflect inflammatory disease activity as assessed by gadolinium-enhancing Magnetic Resonance Imaging (MRI) lesions. Limited data also suggest a decrease in EBV levels following initiation of certain disease-modifying therapies.

CONCLUSION

Heterogeneous methodology limited generalization and meta-analysis. EBV antibody levels are unlikely to represent prognostic biomarkers in MS. The areas of highest ongoing promise relate to diagnostic exclusion and pharmacodynamic/disease response. Use of EBV antibodies as biomarkers in clinical practice remains additionally limited by lack of methodological precision, reliability, and validation.

Comparison of Elecsys and Liaison immunoassays to determine Epstein-Barr virus serological status using further diagnostic approaches to clarify discrepant results

Serological markers for Epstein-Barr virus (EBV) infection are commonly used to diagnose infectious mononucleosis and establish a serological status in pretransplant patients. This study prospectively assessed 1043 serum specimens sent to the laboratory for physician-ordered EBV testing. The three markers-antiviral capsid antigen (VCA) immunoglobulin M (IgM), anti-VCA immunoglobulin G (IgG), and anti-Epstein-Barr nuclear antigen (EBNA) antibodies-were tested using the Elecsys and the Liaison immunoassays. Specimens with discrepant results between the two assays were assessed using further EBV diagnostic approaches to conclude on the EBV serological status. In spite of substantial agreement between the two assays (88%) and with the presumed EBV status (>92%), the results showed differences in the performance of the assays. Liaison VCA IgM appeared to be the most sensitive test for the detection of the 38 sera classified as early primary infection in comparison with the Elecsys assay (91.4% vs. 68.6%, p = 0.008). Excluding the cases of early primary infection, the sensitivity values of the VCA IgM marker were comparable between the Liaison and Elecsys assays (95.2% and 92.9%, respectively, p = 1). Concerning the sera classified as past infection (n = 763), the Elecsys assay showed higher sensitivity values for the detection of the VCA and EBNA IgG markers in comparison with the Liaison assay (99.9% and 99.7% vs. 97.4% and 91.2%, respectively, p < 0.001). Overall, the Elecsys and Liaison assays showed similar performance. The interpretation of EBV serological profiles based on the clinical context may require serology follow up or further diagnostic approaches in challenging cases.

Acute Cytomegalovirus Illness in an Immunocompetent Adult Causing Intravascular Hemolysis and Suspected Hemophagocytic Lymphohistiocytosis

Background

Primary cytomegalovirus (CMV) infection of the immunocompetent host usually produces little-to-no illness. Occasionally, the infection results in mononucleosis syndrome, protracted fever, hepatitis, tissue-invasive disease, or Guillain-Barré syndrome. Hemolytic anemia and hemophagocytic lymphohistiocytosis (HLH) are rare complications that have not been reported to co-occur. Having hemolytic anemia in conjunction with more common findings of fever and hepatitis complicates the diagnosis of HLH. Case Presentation. A 34-year-old male with previously good health presented with a prolonged febrile illness, jaundice, and anemia. An extensive work-up during hospitalization revealed intravascular hemolytic anemia, leukopenia, hepatosplenomegaly, and biopsy evidence of extensive lymphohistiocytic infiltration of the liver with microgranulomata and sinusoidal hemophagocytosis. Soluble CD25 level was mildly elevated at 1200.3 pg/mL and the HScore calculation (fever, bicytopenia, hepatosplenomegaly, aspartate aminotransaminase 99 IU/L, ferritin 1570 ng/mL, fibrinogen 488 mg/dL, and triglycerides 173 mg/dL) suggested a moderate probability of reactive HLH. Primary CMV infection was diagnosed based on CMV IgM positivity, low CMV IgG avidity index, and low-grade CMV DNAemia. The CMV antigen was not detected in the liver biopsy, and the bone marrow biopsy was unremarkable. The illness began to improve before he received oral valganciclovir for 5 days, and he was in good health 10 months later.

Conclusion

Acute CMV illness in an immunocompetent adult can present with hemolytic anemia and clinicopathologic abnormalities consistent with a form fruste of HLH. The illness is likely due to an excessive or unbalanced immune response that may self-correct.

Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Infectious pathogens are implicated in the etiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) because of the occurrence of outbreaks of the disease. While a number of different infectious agents have been associated with the onset of ME/CFS, the identity of a specific organism has been difficult to determine in individual cases. The aim of our study is to survey ME/CFS subjects for evidence of an infectious trigger and/or evidence of immune dysregulation via serological testing of plasma samples for antibodies to 122 different pathogen antigens. Immune profiles were compared to age-, sex-, and BMI-matched controls to provide a basis for comparison. Antibody levels to individual antigens surveyed in this study do not implicate any one of the pathogens in ME/CFS, nor do they rule out common pathogens that frequently infect the US population. However, our results revealed sex-based differences in steady-state humoral immunity, both within the ME/CFS cohort and when compared to trends seen in the healthy control cohort.

Diagnostic value of serological and molecular biological tests for infectious mononucleosis by EBV in different age stages and course of the disease

Epstein-Barr virus (EBV)-based serologic antibody and viral nucleic acid assays have been found to be feasible means to diagnose infectious mononucleosis (IM) caused by EBV in children. In this study, we will further explore their diagnostic value for IM by EBV in different age stages and over the course of the disease. A collection of 616 children from clinically suspected IM cases was studied. Indirect immunofluorescence (IIF) for EBV-specific antibody (Euroimmun) combined with plasma EB viral nucleic acid assay (real-time fluorescence quantitative polymerase chain reaction reverse-transcription polymerase chain reaction) were used as reference methods. The diagnostic efficiency of the peripheral blood routine test, serologic antibody test, and plasma EB viral nucleic acid assay for the diagnosis of IM was evaluated, respectively. The sensitivity, specificity, Youden' index and the area under curve (AUC) were 93.08%, 87.77%, 0.81 and 0.904 (95% confidence interval [CI]: 0.878-0.931) for the peripheral lymphocyte test (lymphocytosis > 5 × 109 /L), 98.27%, 91.13%, 0.89 and 0.947 (95% CI: 0.927-0.967) for the plasma EBV-DNA test, and 84.08%, 96.33%, 0.80 and 0.902 (95% CI: 0.874-0.930) for the EBV viral capsid antigen (VCA)-IgG avidity test. The plasma EBV-DNA test has a higher diagnostic value than the VCA-IgG avidity test in children aged <6 years, especially aged <3 years; the peripheral lymphocyte test and plasma EBV-DNA test are suitable for the early stage of the disease, while the VCA-IgG avidity test for after 7 days of the disease. EBV antibody detection (IIF) should be combined with EBV nucleic acid detection in children age <6 years and the early stage of the disease.

Analytical performance evaluation of the Elecsys Epstein-Barr virus immunoassay panel

We evaluated the analytical performance of the Elecsys® Epstein-Barr virus (EBV) immunoassay panel for the in vitro detection of EBV immunoglobulin M (IgM), EBV viral capsid antigen immunoglobulin G (VCA IgG), and EBV nuclear antigen immunoglobulin G (EBNA IgG). Relative sensitivity/specificity were assessed using 1,734 human blood samples (1,068 residual samples from routine EBV testing; 467 presumed acute infection; 199 presumed seronegative) tested with the Elecsys EBV and 2 comparator panels (ARCHITECT EBV; Liaison EBV). EBV infection status was defined by majority approach. The three panels demonstrated comparable relative sensitivities/specificities, ranging between values (%) of 98.3-99.5 / 96.9-97.4 (EBV IgM); 96.3-98.4 / 98.4-98.7 (EBV VCA IgG); and 98.1-99.5 / 99.1-99.5 (EBV EBNA IgG). The Elecsys EBV IgM assay demonstrated superior analytical specificity in samples containing potential interferents. Utilizing the Elecsys EBV panel for the EBNA-first approach showed 97.5% overall agreement versus the majority approach in samples with clear EBV status.

Primary Epstein-Barr Virus Infection in Healthy Children in Saudi Arabia: A Single Hospital-Based Study

BACKGROUND

Primary Epstein-Barr virus (EBV) infection presents typically with features of infectious mononucleosis (IM) but it may present with atypical symptoms. We aim to evaluate the epidemiological, clinical and laboratory characteristics of primary EBV infection in children in western Saudi Arabia.

METHODS

A retrospective analysis of the electronic data of all children who were admitted to the hospital and were tested for EBV-viral capsid antigen (VCA) IgM in the period from 1 January 2018 to 31 December 2019. All data of the children with positive EBV-VCA IgM were collected. Patients were divided into two groups; IM and the non-typical presentations groups.

RESULTS

Fort-two patients had positive EBV-VCA IgM; 71% had IM and 29% had non-typical presentations. IM was more common in early childhood (46.7%). The non-typical presentations were more in infants below 1 year (50%). Adolescents were less affected (6.7% and 16.7%, respectively). Time to diagnose EBV in the non-typical presentations group was longer than IM group; [3.4 (3.2-4.6) vs. 4.7 (4.1-5.5), p = 0.039]. The total leucocytes count was higher in the IM syndrome group compared to the non-typical presentation group [11 (10.3-17.7) vs. 5.5 (4.5-6.4), p < 0.0001].

CONCLUSIONS

Primary EBV infection in healthy children in Saudi Arabia occurs more frequently in the younger age groups. IM syndrome occurs more frequently in early childhood. The non-typical presentation occurs more frequently in infants. While adolescents are less commonly affected by primary EBV.

Efficacy of Chemiluminescence Immunoassays on VCA-IgA and EBNA1-IgA Antibodies of Epstein-Barr Virus in Diagnosing Nasopharyngeal Carcinoma

Background: IgA antibodies against Epstein-Barr virus (EBV) capsid antigen (VCA) and nuclear antigen 1 (EBNA1) have been proposed to facilitate the diagnosis and early detection of nasopharyngeal carcinoma (NPC) in high-incidence regions. However, while new methodologies and new platforms for the detection of VCA-IgA and EBNA1-IgA have become available, proper interassay simultaneous comparisons have not been carried out. The study was to compare the performance of the chemiluminescent immunoassays (CLIA) and enzyme-linked immunosorbent assay (ELISA) for VCA-IgA and EBNA1-IgA antibodies, and to evaluate the levels of EBV antibodies in healthy population from different areas of China.

Methods: CLIA and ELISA for VCA-IgA and EBNA1-IgA were performed in NPC and healthy populations from high-incidence areas of NPC in South China (N=555), medium-incidence areas of NPC in Central China (N=318) and low-incidence areas of NPC in North China (N=379), and the results were compared and analyzed.

Results: (1) The highest sensitivity in total, early and advanced NPC were 91.5% (CLIA for VCA-IgA), 86.4% (CLIA and ELISA-2 for EBNA1-IgA) and 93.6% (CLIA for VCA-IgA). However, the specificity of EBV-IgA measured by CLIA was relatively lower than ELISA. The top three seromarkers with the largest AUC was CLIA for VCA-IgA (AUC: 0.929, 95% CI: 0.905-0.953), ELISA-2 for EBNA1-IgA (AUC: 0.922, 95% CI: 0.896-0.947) and CLIA for EBNA1-IgA (AUC:0.919, 95% CI: 0.893-0.945), respectively. The positive and negative coincidence rates of the two EBNA1-IgA kits were 69.5% and 91.9%, respectively. However, the coincidence rates of VCA-IgA were relatively low. CLIA kits had good repeatability between different laboratories. (2) The positive rates of EBV-IgA antibodies were relatively high in high-incidence areas of NPC (P < 0.017), while there was no significant difference in the antibody positive rates between medium-incidence areas and low-incidence areas of NPC (P > 0.05).

Conclusions: The performance of EBV-IgA antibodies measured by CLIA has good repeatability, higher sensitivity and similar specificity. The higher EBV-IgA positive rate in healthy subjects by CLIA raises concern about its suitability for NPC-risk screening and requires further analysis.

Preliminary evaluation of a candidate international reference for Epstein-Barr virus capsid antigen immunoglobulin A in China

BACKGROUND

The detection of the Epstein-Barr capsid antigen (VCA) immunoglobulin A (IgA) is widely used in the diagnosis of nasopharyngeal carcinoma (NPC), but a reference standard for evaluating the presence of VCA-IgA is not yet available. Therefore, a reference standard is urgently needed for a uniform and quantitative detection of VCA-IgA.

METHODS

A mixed reference serum from three NPC patients diluted with healthy subject serum was made as a potential first international standard for VCA-IgA. VCA-IgA was detected in twenty NPC patients by four ELISA kits and two chemiluminescent immunoassays kits using the reference as a calibration curve. The performance of these six kits was evaluated, and the quantitative results were compared.

RESULTS

Our results showed a good linearity of the reference in different kits. Without reference, the difference of the total coefficient of variation (from 3.98 to 43.11%) and Within-run coefficient of variation (from 2.47 to 19.66%) was large in the 6 kits. The positive and negative coincidence rate between the 6 kits and indirect immunofluorescence for NPC diagnosis was 75% overall agreement, but a difference among the six kits was found, ranging from 55 to 90%. The concentration of VCA-IgA in the 20 NPC samples led in the division into three categories such as negative, low, or medium/high positive, but these concentrations were significantly different within these three categories depending on the kit used of the 6 considered. However,a good correlation (R² = 0.986) was observed between Antu and Beier ELISA kits.

CONCLUSIONS

The reference serum mightbe used as a reference standard for a better comparison of the results from different kits/laboratories. However, the quantitative results of some kits are still inconsistent due to the diversity of VCA antigens.

S-S-PEG-COOH Self-Assembled Monolayer on Gold Surface Enabled a Combined Assay for Serological EBV Antibody Isotypes

PURPOSE

Epstein-Barr virus (EBV) is a ubiquitous human gamma herpes virus that infects human epithelial cells and B lymphocytes. It would be potentially valuable to develop novel combined assays to benefit screening for large panels of samples of EBV infectious diseases.

EXPERIMENTAL DESIGN

A simple antigen-probed biochip that is modified with S-S-PEG-COOH and is used as a label-free high-throughput screening method for a combined detection of EBV capsid antigen IgM antibody, capsid antigen IgG antibody, and nuclear antigen IgG antibody.

RESULTS

This protein biochip has similar feasibility, sensitivity, and specificity in comparison with Liaison chemiluminescent immunoassay (CLIA). Detection limit of the EBV antibodies by the biochip is almost identical to that by CLIA-L (2.91 U mL^-1 vs 3.00 U mL^-1 for EBNA-1 IgG, 8 U mL^-1 vs10 U mL^-1 for EBV-VCA IgG, and 3.5 U mL^-1 vs 10 U mL^-1 for EBV-VCA IgM). Tests of the three serological antibodies against EBV by the biochip are consistent with the CLIA-L method in 274 clinical sera, respectively. Finally, the combined biochip is successfully utilized for diagnostic identification of EBV infection in 14 patients with infectious mononucleosis (IM) and 25 patients with systemic lupus erythematosus SLE, as well as additional 10 known real-time PCR positive patients.

CONCLUSIONS AND CLINICAL RELEVANCE

This biochip format will enable concurrent detection of antibodies against EBV infection and confirm infection status of EBV. It will be a versatile tool for large-scale epidemiological screening in view of its miniaturization and high throughput.

Diagnostic Performance and Comparative Evaluation of the Architect, Liaison, and Platelia Epstein-Barr Virus Antibody Assays

BACKGROUND

Epstein-Barr Virus (EBV) is one of the most prevalent causes of viral infection in humans. EBV infection stage (acute, past, or absent infection) is typically determined using a combination of assays that detect EBV-specific markers, such as IgG and IgM antibodies against the EBV viral capsid antigen (VCA) and IgG antibodies against the EBV nuclear antigen (EBNA). We compared the diagnostic performance and agreement of results between three commercial EBV antibody assays using an EBV performance panel (SeraCare Life Science, Milford, MA, USA) as a reference.

METHODS

EBV antibody tests of EBV VCA IgM, VCA IgG, and EBNA IgG antibodies were performed by the Architect (Abbott Diagnostics, Wiesbaden, Germany), Liaison (DiaSorin, Saluggia, Italy), and Platelia (Bio-Rad, Marnes-la-Coquette, France) assays. Agreement between the three assays was evaluated using 279 clinical samples, and EBV DNA and antibody test results were compared.

RESULTS

The three EBV antibody assays showed good diagnostic performance with good and excellent agreement with the performance panel (kappa coefficient, >0.6). The overall VCA IgM positivity rate was higher in EBV DNA-positive samples than in EBV DNA-negative samples for all three EBV antibody assays (P=0.02). The three EBV antibody assays exhibited good agreement in results for the clinical samples.

CONCLUSIONS

The diagnostic performance of the three EBV antibody assays was acceptable, and they showed comparable agreement in results for the clinical samples.

Epstein-Barr Virus Epidemiology, Serology, and Genetic Variability of LMP-1 Oncogene Among Healthy Population: An Update

The Epstein-Barr virus (EBV) is a DNA lymphotropic herpesvirus and the causative agent of infectious mononucleosis. EBV is highly prevalent since it affects more than 90% of individuals worldwide and has been linked to several malignancies including PTLDs, which are one of the most common malignancies following transplantation. Among all the EBV genes, most of the recent investigations focused on studying the LMP-1 oncogene because of its high degree of polymorphism and association with tumorigenic activity. There are two main EBV genotypes, Type 1 and 2, distinguished by the differences in the EBNA-2 gene. Further sub genotyping can be characterized by analyzing the LMP-1 gene variation. The virus primarily transmits through oral secretions and persists as a latent infection in human B-cells. However, it can be transmitted through organ transplantations and blood transfusions. In addition, symptoms of EBV infection are not distinguishable from other viral infections, and therefore, it remains questionable whether there is a need to screen for EBV prior to blood transfusion. Although the process of leukoreduction decreases the viral copies present in the leukocytes, it does not eliminate the risk of EBV transmission through blood products. Here, we provide a review of the EBV epidemiology and the genetic variability of the oncogene LMP-1. Then, we underscore the findings of recent EBV seroprevalence and viremia studies among blood donors as a highly prevalent transfusion transmissible oncovirus.

Prevalence and molecular profiling of Epstein Barr virus (EBV) among healthy blood donors from different nationalities in Qatar

BACKGROUND

The Epstein-Barr virus (EBV) is the causative agent of infectious mononucleosis. EBV is highly prevalent lymphotropic herpesvirus and has been linked to several malignancies. Transmission is generally by oral secretions, but can be through blood transfusions and organ transplantations. This study aimed to determine the seroprevalence, viremia rates, and circulating genotypes of EBV in healthy blood donors in Qatar.

METHODS

Blood samples from 673 blood donors of different nationalities residing in Qatar (mainly Qatar, Egypt, Syria, Jordan, Pakistan, and India) were collected and tested for anti-EBV capsid (VCA; IgG & IgM), nuclear (EBNA; IgG), and early (EA-D; IgG) antigens. Avidity testing was determined when active infection was suspected. DNA was extracted from the buffy coat and subjected to EBV-DNA quantification using qRT-PCR. Genotyping was performed using nested-PCR targeting EBV-EBNA2 gene, and phylogeny by sequence analysis of the LMP-1 gene.

RESULTS

97.9% (673/659) of the samples were seropositive as indicated by the presence VCA-IgG, while 52.6% (354/673) had detectible EBV-DNA. EBV seroprevalence and viremia rates increased significantly with age. Genotyping of 51 randomly selected samples showed predominance of Genotype 1 (72.5%, 37/51) as compared to genotype 2 (3.5%), and mixed infections were detected in 4% of the samples. Sub-genotyping for these samples revealed that the Mediterranean strain was predominant (65.3%), followed by B95.8 prototype and North Carolina strains (12.2% each), and China1 strain (6%).

CONCLUSION

As a first study to evaluate EBV infection in highly diverse population in Qatar, where expatriates represent more than 85% of the population, our results indicated high seroprevalence and viremia rate of EBV in different nationalities, with genotype 1 and Mediterranean strain being predominant. Clinical significance of these finding have not been investigated and shall be evaluated in future studies.

Comparison of Abbott Architect®, Siemens Immulite®, and Diasorin Liaison® for determination of Epstein-Barr virus serological diagnosis

This study compared the performance of 3 automated immunoassays, Architect^® (Abbott), Immulite^® (Siemens) and Liaison^® (Diasorin), for Epstein-Barr virus (EBV) serology. Ninety-one serum samples collected in Amiens University Hospital were analyzed for the presence of Viral Capsid Antigen (VCA) IgG and IgM and Epstein-Barr Nuclear Antigen (EBNA) IgG. The agreement between the 3 assays was calculated for each marker individually and for determination of the EBV profile, based on interpretation of the combination of these 3 EBV markers. Although similar results were obtained with Architect^® and Liaison^®, several discordant results were observed with Immulite^®, particularly for EBNA IgG. A large number of EBNA IgG-positive results were observed, which interfered with interpretation of the EBV profile. In contrast, Immulite^® performed similarly to the 2 other assays for detection of VCA IgM.

Pediatric Kikuchi-Fujimoto disease: A clinicopathologic study and the therapeutic effects of hydroxychloroquine

BACKGROUND

To investigate the clinical features of Kikuchi-Fujimoto disease (KFD) in children, and place an emphasis on the therapeutic effects of hydroxychloroquine as monotherapy.

METHODS

We retrospectively reviewed the medical records of all children diagnosed with KFD during the period January 1992 to September 2016 at a tertiary medical center in Taiwan.

RESULTS

40 patients were histopathologically confirmed as KFD, and the mean age of the patients was 13.9 ± 3.1 years. The male to female ratio was 1:1. The lymph node involvements were often cervical (95%) with features of unilateral predisposition (75%), polyadenopathy (84.4%) and tenderness (56.3%). Fever, cough, rhinorrhea, and tonsillitis were other common presentations. Laboratory findings included leukopenia (56.5%), monocytosis (63.6%), with positive results of EB-VCA IgG (88.9%), EB-VCA IgM (22.2%), EBEA IgG (22.2%) and EBNA IgG (88.9%). The univariate analyses of prolonged fever with lymphopenia, monocytosis, thrombocytopenia and necrotizing type in histopathology were disclosed as statistically significant (P < 0.05). Corticosteroids and hydroxychloroquine were administered in 15.6% of patients respectively, along with symptomatic treatments for the rest. Recurrence occurred in 13.0% of patients without corticosteroids or hydroxychloroquine treatment. There were neither recurrences nor relevant major adverse effects in all the five KFD cases treated with hydroxychloroquine.

CONCLUSION

KFD should be suspected in children with febrile cervical lymphadenopathy, especially when concomitant with leukopenia and monocytosis. Lymphopenia, monocytosis, thrombocytopenia and necrotizing type in histopathology are reliable predictors for prolonged fever. Hydroxychloroquine may be an alternative choice to corticosteroids for its favorable effects and safety.

Rapid diagnosis in serology

Serological diagnosis of acute phase infections implies the detection of IgM specific response, an effective marker of primary infection, but with less clinical significance in reactivations or reinfections. The aim of this article is to provide an updated view of the rapid diagnosis in serology by detecting the IgM isotype and reviewing its applications and limitations. Point-of-care (PoC) tests are analyzed. PoC tests are used in geographical areas where traditional tests are not available, as well as in other circumstances where their use brings the diagnosis directly to the target population. Likewise, their use reduces the response time between taking the sample and the diagnosis, making it easier to make clinical decisions. PoC assays have proven cost-effective, especially in preventing vertical transmission of syphilis and HIV infection.

Evaluation of the abbot Architect(™) epstein-barr virus viral capsid antigen IgM, viral capsid antigen IgG and nuclear antigen IgG assays in a pediatric and adult population

BACKGROUND

The detection of antibodies against Epstein-Barr viral capsid (VCA) and nuclear (EBNA) antigens is routinely performed with different commercially available immunoassays.

OBJECTIVES

In this study, we evaluated the concordance and performance of the Architect(™) chemiluminescent microparticle immunoassays (CMIAs) using Captia(™) enzyme linked immunosorbent assays (ELISA) for VCA IgM, and standard immunofluorescence (IF) assays for VCA IgG and EBNA IgG as comparative techniques.

STUDY DESIGN

Sera were selected from a heterogeneous population including pediatric and adult patients.

RESULTS

Concordance between CMIAs and comparative assays was high with total agreement percentages of 84,1% (95% CI: 77.8-88.9) for VCA IgM, 90,6% (95% CI: 84.2-94.7) for EBNA IgG and 98,0% (95% CI: 93.9-99.6) for VCA IgG. Moreover, kappa statistic values showed good to excellent correlation with values of 0.68 (95% CI: 0.57-0.79) for VCA IgM, 0.73 (95% CI: 0.58-0.87) for EBNA IgG and 0.95 (95% CI: 0.89-1.00) for VCA IgG. A correlation was observed between positivity levels on CMIAs and semi-quantitative fluorescence intensity on IF for VCA IgG and EBNA IgG assays. With regard to an accepted gold standard IF assays, CMIA was 98,1% (95% CI: 93.3-99.8) sensitive and 97,4% (95% CI: 86.5-99.9) specific for the detection of VCA IgG. For the detection of EBNA IgG, it was 92,2% (95% CI: 85.1-96.6) sensitive and 84,6% (95% CI: 65.1-95.6) specific.

CONCLUSION

In summary, we demonstrated that the CMIA EBV antibody detection panel has high performance and high concordance with other commercially available immunoassays.

Epstein-Barr virus and multiple sclerosis. From evidence to therapeutic strategies

Multiple sclerosis is caused by a complex interaction between genetic predisposition and environmental factors. Epstein-Barr virus (EBV) is an environmental risk factor that is strongly related to multiple sclerosis (MS), since EBV seropositivity is linked to a significant risk of developing MS. EBV may be involved in the pathogenesis of the disease and it is possibly a prerequisite for the development of MS. EBV infection persists in B-cells during the lifetime of the host and can modulate their function. In addition, MS patients might have a deficient capacity to eliminate latent EBV infection in the central nervous system and this would promote the accumulation of infected B cells. Several mechanisms of pathogenesis, including a direct and indirect function of infected B cells, have been postulated in inflammation and neurodegeneration. A relationship between EBV and human endogenous retroviruses in the pathogenesis of MS has also been reported. If EBV is important in the pathogenesis of MS, different therapeutic strategies seem possible for MS treatment.

Conversion from clinically isolated syndrome to multiple sclerosis: A large multicentre study

Background and objective:

We explored which clinical and biochemical variables predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) in a large international cohort.

Methods:

Thirty-three centres provided serum samples from 1047 CIS cases with at least two years’ follow-up. Age, sex, clinical presentation, T2-hyperintense lesions, cerebrospinal fluid (CSF) oligoclonal bands (OCBs), CSF IgG index, CSF cell count, serum 25-hydroxyvitamin D3 (25-OH-D), cotinine and IgG titres against Epstein-Barr nuclear antigen 1 (EBNA-1) and cytomegalovirus were tested for association with risk of CDMS.

Results:

At median follow-up of 4.31 years, 623 CIS cases converted to CDMS. Predictors of conversion in multivariable analyses were OCB (HR = 2.18, 95% CI = 1.71–2.77, p < 0.001), number of T2 lesions (two to nine lesions vs 0/1 lesions: HR = 1.97, 95% CI = 1.52–2.55, p < 0.001; >9 lesions vs 0/1 lesions: HR = 2.74, 95% CI = 2.04–3.68, p < 0.001) and age at CIS (HR per year inversely increase = 0.98, 95% CI = 0.98–0.99, p < 0.001). Lower 25-OH-D levels were associated with CDMS in univariable analysis, but this was attenuated in the multivariable model. OCB positivity was associated with higher EBNA-1 IgG titres.

Conclusions:

We validated MRI lesion load, OCB and age at CIS as the strongest independent predictors of conversion to CDMS in this multicentre setting. A role for vitamin D is suggested but requires further investigation.

Performance of the architect EBV antibody panel for determination of Epstein-Barr virus infection stage in immunocompetent adolescents and young adults with clinical suspicion of infectious mononucleosis

The Architect EBV antibody panel is a new chemiluminescence immunoassay system used to determine the stage of Epstein-Barr virus (EBV) infection based on the detection of IgM and IgG antibodies to viral capsid antigen (VCA) and IgG antibodies against Epstein-Barr nuclear antigen 1 (EBNA-1). We evaluated its diagnostic accuracy in immunocompetent adolescents and young adults with clinical suspicion of infectious mononucleosis (IM) using the RecomLine EBV IgM and IgG immunoblots as the reference standard. In addition, the use of the antibody panel in a sequential testing algorithm based on initial EBNA-1 IgG analysis was assessed for cost-effectiveness. Finally, we investigated the degree of cross-reactivity of the VCA IgM marker during other primary viral infections that may present with an EBV IM-like picture. High sensitivity (98.3% [95% confidence interval {CI}, 90.7 to 99.7%]) and specificity (94.2% [95% CI, 87.9 to 97.8%]) were found after testing 162 precharacterized archived serum samples. There was perfect agreement between the use of the antibody panel in sequential and parallel testing algorithms, but substantial cost savings (23%) were obtained with the sequential strategy. A high rate of reactive VCA IgM results was found in primary cytomegalovirus (CMV) infections (60.7%). In summary, the Architect EBV antibody panel performs satisfactorily in the investigation of EBV IM in immunocompetent adolescents and young adults, and the application of an EBNA-1 IgG-based sequential testing algorithm is cost-effective in this diagnostic setting. Concomitant testing for CMV is strongly recommended to aid in the interpretation of EBV serological patterns.

Application of a commercial immunoblot to define EBV IgG seroprofiles

BACKGROUND

Immunoblot (IB) techniques using different Epstein-Barr virus (EBV) antigens have been applied for detecting specific antibodies, making possible to obtain EBV seroprofiles in a single determination. The aim of this study was to evaluate a commercial IB for the detection of EBV-specific IgG (Euroimmun, Lübeck, Germany).

METHODS

A total of 117 samples classified as EBV primary recent infections (n = 70), past infections (n = 29), or not infected (n = 18) have been used. The samples were characterized by immunofluorescence, by testing EBV capsid antigens IgM and IgG (using indirect approaches) and EBV nuclear antigen (by anticomplement technique; Meridian Bioscience Inc.).

RESULTS

Using the cut-off value as defined by the IB manufacturer, the concordance, relative sensitivity, and relative specificity were 85.5 (100/117), 94.3% (66/70), and 72.3% (34/47), respectively. If a corrected cut-off value was considered to classify the samples, the corresponding corrected figures were 89.7, 88.6, and 91.5%, respectively.

CONCLUSION

Being a useful serological diagnostic tool, IB for testing EBV IgG seems to be an adequate approach to define EBV seroprofiles. However, efforts to better define the cut-off value should be made in order to improve the performance of the assay in evaluation.

Evaluation of the Architect Epstein-Barr Virus (EBV) viral capsid antigen (VCA) IgG, VCA IgM, and EBV nuclear antigen 1 IgG chemiluminescent immunoassays for detection of EBV antibodies and categorization of EBV infection status using immunofluorescence assays as the reference method

Commercial immunoassays for detecting IgG and IgM antibodies against Epstein-Barr virus (EBV), viral capsid antigens (VCA), and IgGs toward EBV nuclear antigen-1 (EBNA-1) are routinely used in combination to categorize EBV infection status. In this study, we evaluated the performances of the Architect EBV VCA IgG, VCA IgM, and EBNA-1 IgG chemiluminescent microparticle assays (CMIAs) in EBV serological analyses using indirect immunofluorescence assays and anticomplement immunofluorescence assays as the reference methods for VCA IgG, VCA IgM, and EBNA-1 IgG antibody detection, respectively. A total of 365 serum samples representing different EBV serological profiles were included in this study. The κ values (concordances between the results) obtained in the Architect CMIA and those in the reference assays were 0.905 (P < 0.0001) for VCA IgM, 0.889 (P < 0.0001) for VCA IgG, and 0.961 (P < 0.0001) for EBNA-1 IgG. The sensitivities and specificities were, respectively, 91.08% and 99.48% for VCA IgM, 99.23% and 86.27% for VCA IgG, and 96.77% and 99.16% for EBNA-1 IgG. The sensitivities and specificities of the Architect CMIA panel were, respectively, 99.15% and 98.6% for diagnosing a primary infection, 97.62% and 93.39% for diagnosing a past EBV infection, and 92.42% and 97.82% for diagnosing the absence of an EBV infection. In summary, we demonstrated that the Architect EBV antibody panel performs very well for EBV antibody detection and correctly categorizes clinically relevant EBV infection states.

Epstein-Barr virus and multiple sclerosis: association or causation?

Multiple sclerosis (MS) is a multifactorial disease in which both genetic and environmental factors and their interactions underlie causation. The current evidence base supports a strong association between Epstein-Barr virus (EBV) and MS, but potential causality remains strongly debated. It is not possible to exclude the possibility that an abnormal response to EBV infection is a consequence, rather than a cause, of the underlying pathophysiology of MS, or indeed that the association may be a reflection of a similar underlying disease mechanism. Substantial experimental progress is necessary to achieve consistency of molecular findings to complement the strong epidemiological association between EBV and MS, which cannot alone show causation. Collectively, the strength of the association between EBV and MS warrants careful development and trial of anti-EBV drugs to observe any effect on MS disease course.

Diverse IgG serum response to novel glycopeptide epitopes detected within immunodominant stretches of Epstein-Barr virus glycoprotein 350/220: diagnostic potential of O-glycopeptide microarrays

The Epstein-Barr virus (EBV) envelope glycoprotein 350/220 (gp350/220) is the most abundant molecule on the viral surface and it is responsible for the initial viral attachment to cell surface of the host. As many other viral envelope proteins, it is highly glycosylated, not least with O-linked glycans, most of which essential for EBV life cycle. EBV gp350/220 is also a primary target for neutralizing antibodies in the human hosts and a promising candidate for an EBV vaccine. Here we showed that recombinant GalNAc transferases can glycosylate scan peptides of the EBV gp350/220 envelope protein immobilized on microarray glass slides. We also identified serum IgG antibodies to a selection of peptides and O-glycopeptides, whereas sera from EBV-IgG negative individuals remained negative. We here describe novel glycopeptide epitopes present within immunodominant stretches of EBV gp350/220 and demonstrate a remarkable variability between individual samples with respect to their reactivity patterns to peptides and glycopeptides. The study provides additional insights into the complex B-cell response towards the EBV gp350/220 envelope protein, which may have implications for diagnostic and vaccine developments.

Epstein-Barr virus, latitude and multiple sclerosis

Several lines of evidence support a role for Epstein-Barr virus (EBV) in the aetiology of multiple sclerosis (MS). This includes the observation that nearly all MS patients show serological markers of past EBV infection. Given the well-known association between MS prevalence and latitude, we investigated whether EBV seropositivity also increases with distance from the equator. We found that the proportion of EBV positive individuals is positively associated with latitude independently of MS status (odds ratio = 1.06, 95% CI = 1.02-1.09, p = 0.002). Latitude-related factors may be implicated in the immune response to EBV and its role in MS aetiology.

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.

Serological diagnosis of Epstein-Barr virus infection: Problems and solutions

Serological tests for antibodies specific for Epstein-Barr virus (EBV) antigens are frequently used to define infection status and for the differential diagnosis of other pathogens responsible for mononucleosis syndrome. Using only three parameters [viral capsid antigen (VCA) IgG, VCA IgM and EBV nuclear antigen (EBNA)-1 IgG],it is normally possible to distinguish acute from past infection: the presence of VCA IgM and VCA IgG without EBNA-1 IgG indicates acute infection, whereas the presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection. However, serological findings may sometimes be difficult to interpret as VCA IgG can be present without VCA IgM or EBNA-1 IgG in cases of acute or past infection, or all the three parameters may be detected simultaneously in the case of recent infection or during the course of reactivation. A profile of isolated EBNA-1 IgG may also create some doubts. In order to interpret these patterns correctly, it is necessary to determine IgG avidity, identify anti-EBV IgG and IgM antibodies by immunoblotting, and look for heterophile antibodies, anti-EA (D) antibodies or viral genome using molecular biology methods. These tests make it possible to define the status of the infection and solve any problems that may arise in routine laboratory practice.

Validity of a point-of-care based on heterophile antibody detection for the diagnosis of infectious mononucleosis in primary care

OBJECTIVE

To evaluate the validity of a point-of-care test to diagnose infectious mononucleosis (IM) compared with Epstein-Barr virus (EBV) specific serology.

METHODS

Patients over 14 years with sore throat and four Centor criteria--tonsillar exudate, fever, lymph glands tenderness and absence of cough--and negative pharyngeal testing for group A β-haemolytic streptococcal antigen were consecutively recruited. All patients underwent pharyngotonsillar swab for microbiological culture, the rapid OSOM MonoTest for the diagnosis of IM in whole blood, the Paul-Bunnell test and complete blood analysis with serology for EBV and cytomegalovirus the day after the visit and at 15 days. Sensitivity and specificity were determined.

RESULTS

We included 145 patients with a mean age of 24 ± 6.8 years. Of these, serology was determined in 129 subjects, with IM being diagnosed in 14 (10.9%). Both the MonoTest and the Paul-Bunnell test were positive in 13 patients with IM (92.9%) with no patient without disease being positive for either test--sensitivity of 92.9% (95% CI: 64.2-99.6%) and specificity of 100% (95% CI: 96-100%). The culture showed streptococcus A infection in 1 case (0.7%) and streptococcus C in 62 cases (42.8%). A total of 78 patients presented past infection by EBV (60.5%).

CONCLUSIONS

Only one out of 10 patients with sore throat, four Centor criteria and negative rapid test for streptococcal infection presents IM. Despite the MonoTest presenting optimum sensitivity and specificity, it was found to have the same validity as the Paul-Bunnell test, with serological study continuing to be necessary for precise diagnosis of IM.