Assessment of rapid ELISA test for detection of Epstein-Barr virus infection

Evaluation the Architect EBV VCA IgM, VCA IgG, and EBNA-1 IgG chemiluminescent immunoassays to assess EBV serostatus prior transplantation

Prior to transplantation of hematopoietic stem cells or solid organ, donor and recipient EBV serostatus has to be determined to assess risks of post-transplant lymphoproliferative disorders. Sensitivity of EBV Viral capsid antigens (VCA) IgG and EBV nuclear antigen-1 (EBNA-1) is critical to define past infection and a good specificity of VCA IgM is required to avoid any disqualification of cord blood (CB) units. Architect™ EBV antibody panel (Architect assay) providing a high throughput was compared to a semi-automated ELISA (Etimax assays Diasorin) to assess sensitivities and specificities of VCA and EBNA-1 IgG and VCA IgM on 419 sera collected from immunocompromised patients (n = 184) and from pregnant women who agreed to give CB cells (n = 235). Intra and inter-assay coefficient of variations ranged from 1.63% to 4.8% for VCA IgM, VCA IgG, and EBNA-1 IgG. Index of VCA IgG and IgM and EBNA IgG of the two assays were highly correlated. The concordance in the interpretation between the two assays was moderate for VCA IgM (kappa = 0.5), substantial for VCA IgG (kappa = 0.60) and good for EBNA-1 IgG (kappa = 0.75). Using serial dilutions of positive controls and in accordance with clinical results VCA IgG and EBNA IgG were detected at lower dilutions with Architect than Etimax. Conversely, 96.1% (74/77) of samples negative with Architect and positive with Etimax for VCA IgM did not have any heterophile antibodies and had VCA IgG and EBNA IgG antibodies supporting past infections. Architect™ EBV serology panel provided good sensitivities and specificities for EBV serostatus determination prior to transplantation.

Fluorescence in situ hybridization is superior for monitoring Epstein Barr viral load in infectious mononucleosis patients

BACKGROUND

Epstein Barr virus (EBV) plays a causal role in some diseases, including infectious mononucleosis, lymphoproliferative diseases and nasopharyngeal carcinoma. Detection of EBV infection has been shown to be a useful tool for diagnosing EBV-related diseases. In the present study, we compared the performance of molecular tests, including fluorescence in situ hybridization (FISH) and EBV real-time PCR, to those of serological assays for the detection of EBV infection.

METHODS

Thirty-eight patients with infectious mononucleosis (IM) were enrolled, of whom 31 were diagnosed with a mild type, and seven were diagnosed with IM with haemophagocytic lymphohistiocytosis and chronic active EBV infection. Twenty healthy controls were involved in the study. The atypical lymphocytes in peripheral blood were detected under a microscope and the percentage of positive cells was calculated. EBV DNA load in peripheral blood was detected using real-time PCR. The FISH assay was developed to detect the EBV genome from peripheral blood mononuclear cells (PBMC). Other diagnosis methods including the heterophil agglutination (HA) test and EBV-VCA-IgM test, to detect EBV were also compared. SPSS17.0 was used for statistical analysis.

RESULTS

In all, 5-41% atypical lymphocytes were found among the PBMC in mild IM patients, whereas 8-51% atypical lymphocytes were found in IM patients with haemophagocytic lymphohistiocytosis and chronic active EBV infection patients. There was no significant difference in the ratios of atypical lymphoma between patients of the different types. We observed that 71.2% of mild IM patients and 85.7% of IM patients with haemophagocytic lymphohistiocytosis and chronic active EBV infection patients were positive for EBV-VCA-IgM. EBV-VCA-IgM was negative in all healthy control subjects. In addition, 67.1% of mild IM patients tested heterophile antibody positive, whereas 71.4% of IM patients with haemophagocytic lymphohistiocytosis and chronic active EBV infection tested positive. EBV DNA detected using real-time PCR was observed in 89.5% of these IM patients. The EBV genome was detected by the FISH assay in 97.4% of the IM patients. The EB viral loads detected by FISH and real-time PCR increased with the severity of IM. The EBV genome was detected in almost all the PBMC of IM with haemophagocytic lymphohistiocytosis and chronic active EBV infection patients.

CONCLUSION

Molecular tests, including FISH and EBV real-time PCR, are more sensitive than serological assays for the detection of EBV infection. The FISH assay detecting EBV copies in unfractionated whole blood is preferable and superior to plasma real-time PCR in its reflection of the absolute viral burden circulating in the patients.

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.

Diagnostic performance of a new automated heterophile antibody test in adults and children

Epstein-Barr virus serologic profiles were obtained from 618 patients using an automated platform, including the new BioPlex heterophile assay. When compared with 2 IgM viral capsid antigen (VCA) assays and a predicate heterophile assay, the BioPlex heterophile assay was more likely to be associated with serologic patterns of acute infection.

Epstein-Barr Virus Serostatus

PURPOSE

To investigate the Epstein-Barr virus (EBV) serostatus in an athletic endurance population, especially the prevalence of complex aberrant EBV antibody patterns. In addition, the purpose was to determine whether serology in athletes is more complex than in the general population.

METHODS

The study protocol included serological testing of 202 advanced endurance athletes (biathlon, cycling, nordic skiing (state to international level); mean age 19 +/- 4) and 200 control subjects (mean age 23 +/- 2). Twenty-microliter serum samples were examined using a strip immunoassay with antigens produced by recombinant techniques for detection of EBV IgG antibodies: anti-EBNA-1 (anti-EBV nuclear antigen-1), anti-p18, anti-p23, anti-p138, anti-p54, and anti-BZLF-1. Avidity determination was used to differentiate further between acute, recent, and past infections.

RESULTS

Athletes showed 35 negative (17%), 6 unresolvable (3%), 1 acute (0.5%), 11 recent (5%), 122 past (61%), and 27 aberrant past (mainly anti-EBNA-1 negative) (13.5%) cases. The control group showed 31 negative (16%), 4 unresolvable (2%), 1 acute (0.5%), 1 recent (0.5%), 135 past (68%), and 28 (14.0%) aberrant past cases. Although endurance athletes included more recent infections (several months since acute infection), there was no significant difference (P = 0.144) in the total constellation of EBV serostatus between the groups.

CONCLUSION

No evidence was found for the assumption that endurance athletes are more susceptible to EBV infections than the general population. In addition, no differences were found with respect to serological classical and aberrant complicated patterns between athletes and the control group. Those cases that may lead to false diagnoses of acute EBV infection in previously used test systems because of a negative anti-EBNA-1 are common in both groups but were unambiguously resolved by the Recomline EBV IgG test applied here.

Detection of EBV-DNA in serum samples of an immunosuppressed child during a three years follow-up: association of clinical and PCR data with active infection

Twenty-four whole blood and serum samples were drawn from an eight year-old heart transplant child during a 36 months follow-up. EBV serology was positive for VCA-IgM and IgG, and negative for EBNA-IgG at the age of five years old when the child presented with signs and symptoms suggestive of acute infectious mononucleosis. After 14 months, serological parameters were: positive VCA-IgG, EBNA-IgG and negative VCA-IgM. This serological pattern has been maintained since then even during episodes suggestive of EBV reactivation. PCR amplified a specific DNA fragment from the EBV gp220 (detection limit of 100 viral copies). All twenty-four whole blood samples yielded positive results by PCR, while 12 out of 24 serum samples were positive. We aimed at analyzing whether detection of EBV-DNA in serum samples by PCR was associated with overt disease as stated by the need of antiviral treatment and hospitalization. Statistical analysis showed agreement between the two parameters evidenced by the Kappa test (value 0.750; p < 0.001). We concluded that detection of EBV-DNA in serum samples of immunosuppressed patients might be used as a laboratory marker of active EBV disease when a Real-Time PCR or another quantitative method is not available.

Cellular and humoral immune abnormalities in Gulf War veterans

We examined 100 symptomatic Gulf War veterans (patients) and 100 controls for immunologic assays. The veterans and controls were compared for the percentage of T cells (CD3); B cells (CD19); helper:suppressor (CD4:CD8) ratio; natural killer (NK) cell activity; mitogenic response to phytohemagglutin (PHA) and pokeweed mitogen (PWM); level of immune complexes; myelin basic protein (MBP) and striated and smooth muscle autoantibodies; and antibodies against Epstein-Barr virus, cytomegalovirus, herpes simplex virus type 1 (HSV-1), HSV-2, human herpes Type 6 (HHV-6), and Varicella zoster virus (VZV). The percentage of T cells in patients versus controls was not significantly different, whereas a significantly higher proportion of patients had elevated T cells compared with controls. The percentage of B cells was significantly elevated in the patients versus the controls. The NK cell (NK) activity was significantly decreased in the patients (24.8 +/- 16.5 lytic units) versus the controls (37.3 +/- 26.4 lytic units). The percentage of patients with lower than normal response to PHA and PWM was significantly different from controls. Immune complexes were significantly increased in the patients (53.1 +/- 18.6, mean +/- SD) versus controls (34.6 +/- 14.3). Autoantibody titers directed against MBP and striated or smooth muscle were significantly greater in patients versus controls. Finally, the patients had significantly greater titers of antibodies to the viruses compared with the controls (p < 0.001). These immune alterations were detected 2-8 years after participation in the Gulf War. The immune alterations are consistent with exposure to different environmental factors. We conclude that Gulf War syndrome is a multifaceted illness with immune function alterations that may be induced by various factors and are probably associated with chronic fatigue syndrome.

Epstein-Barr virus (EBV) DNA in sera of patients with primary EBV infection

Detection of Epstein-Barr Virus (EBV) DNA by PCR in serum had a sensitivity of 80%, a specificity of 94%, and positive and negative predictive values of 95 and 79%, respectively, for the diagnosis of primary EBV infection. We suggest that this is a useful addition to the panel of tests used for this purpose.

Epstein-Barr virus (EBV) DNA in sera of patients with primary EBV infection

Detection of Epstein-Barr Virus (EBV) DNA by PCR in serum had a sensitivity of 80%, a specificity of 94%, and positive and negative predictive values of 95 and 79%, respectively, for the diagnosis of primary EBV infection. We suggest that this is a useful addition to the panel of tests used for this purpose.

Development and evaluation of an Epstein-Barr virus (EBV) immunoglobulin M enzyme-linked immunosorbent assay based on the 18-kilodalton matrix protein for diagnosis of primary EBV infection

A new immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) based on the recombinant Epstein-Barr virus (EBV) matrix protein was developed. Compared to indirect immunofluorescence for the detection of IgM antibody to the EBV capsid antigen on clinical specimens, the sensitivity and specificity of the new IgM ELISA were 96 and 96%, respectively.

Evaluations of enzyme-linked immunosorbent assay procedure for determining specific Epstein-Barr virus serology and of rapid test kits for diagnosis for infectious mononucleosis

Using the results of Epstein-Barr virus-specific immunofluorescence serology as the "gold standard," we found that the sensitivities of the five rapid test kits varied from 78 to 84% and specificities varied from 89 to 100%. Enzyme-linked immunosorbent assay-determined specific Epstein-Barr virus antibody profiles had a sensitivity and specificity of 98.6 and 95.5%, respectively.

Difficulties with the serologic diagnosis of infectious mononucleosis: a review of the RCPA quality assurance programs

The Royal College of Pathologists of Australasia's Quality Assurance Programs (QAP) on serologic assays for infectious Mononucleosis (IM) have identified a number of important problems in laboratory diagnosis of this condition. A wide range of assays for the diagnosis of acute Epstein-Barr virus (EBV) infection are available, although heterophile antibody tests are still the most frequently performed procedures for the diagnosis of IM. In 1993, eighty-six (54%) of the 159 participating laboratories performed only a heterophile test; of these, 71% did not provide an interpretation of their results and none mentioned the need for confirmatory EBV-specific antibody testing. This revealed a lack of appreciation that heterophile tests should only be used for screening, due to their inferior sensitivity of less than 50% in children and 80-90% in adults and specificity of 95% compared to EBV-specific assays. For these reasons the use of heterophile tests is discouraged. Although EBV-specific serology has traditionally been done by immunofluorescence (IF), the use of reliable ELISA methods using purified EBV-antigens is increasing. False negative EBV VCA IgM ELISA test results were obtained by laboratories using unpurified or unspecified VCA antigens. As only five laboratories used these tests in the 1992 QAP, the tests' true performances could not be properly assessed, suggesting the need for independent studies. Variable results were obtained by laboratories using commercial EBNA IgG assays (in addition to EBV IgM) suggesting that an assessment of these kits would also be worthwhile. The QAP reaffirm that reliable EBV IgM detection is the most useful test for the diagnosis of IM, even where other EBV markers are also used. In the 1992 and 1993 QAP, laboratory performance of both heterophile and EBV-specific tests was better with non-reactive serum specimens (99% (correct) than with reactive serum specimens (90% correct).

Infectious Mononucleosis

In brief A two-step infection by the Epstein-Barr virus accounts for the characteristic features of infectious mononucleosis (IM). New serologic tests for viral antigens exist, but a rapid kit test for heterophil antibody usually suffices to confirm the diagnosis. General management is supportive only. Splenic rupture is very rare, almost never fatal if diagnosed early, and, in most cases, is probably best treated by splenectomy. Athletes tend to recover from IM faster than nonathletes. When the spleen returns to normal size, the athlete can return to contact sports, though it may take 3 to 6 months for an elite athlete to regain top form.

Avidity of EBV VCA-specific IgG antibodies: distinction between recent primary infection, past infection and reactivation

A commercial Epstein-Barr virus (EBV) antivirus capsid antigen (VCA) IgG antibody ELISA and an 'in-house' EBV VCA IgG immunofluorescence antibody assay (IFA) were used to detect EBV VCA IgG antibodies in 100 serum samples collected from organ transplant recipients and immunocompetent individuals. The avidity of EBV VCA IgG antibodies was determined in the IFA and ELISA using the mild reducing agent 8 M urea to remove low avidity antibodies. The samples were collected from patients who had previously been identified with a primary EBV infection, a reactivation of latent infection or evidence of a past EBV infection by means of EBV-specific serology. Using the ELISA, the antibody avidity was low in samples collected from patients with recent EBV infection and high in samples collected from patients with a past infection or a reactivation. There was a statistically significant difference of means (P < 0.001) of percentage reduction in optical density values, measured in the presence of 8 M urea, obtained with samples collected from patients with recent infection compared with samples from patients with a past infection or a reactivation of latent infection.

The rapid serological diagnosis of infectious mononucleosis

A total of 121 samples of serum collected from 101 patients was tested to determine the sensitivity and specificity of a commercial latex agglutination test for detecting infectious mononucleosis heterophile antibody, a commercial immunofluorescence test for detecting antibody to Epstein-Barr virus capsid antigen and a rapid enzyme immunoassay for detecting antibody to Epstein-Barr virus nuclear antigen. Although the Epstein-Barr virus capsid antigen IgM indirect immunofluorescence test proved to be the most sensitive, false-positive reactions were seen when samples collected from patients with cytomegalovirus, hepatitis A virus, parvovirus and leptospira infection were tested. False-positive reactions were also seen with samples containing rheumatoid factor.