Epstein-Barr Virus

Epstein-Barr virus (EBV) is the cause of a variety of disorders, including mononucleosis.

Epidemiology

Age – usually <21 years
- 50% seropositive <5 years
Transmission – salivary contact

Organism

Gamma herpesvirus that belongs to the Herpesviridae family
Like other herpes viruses, may remain dormant for years as a latent infection
- Infects B lymphocytes, which can then be reactivated

Clinical Presentation

Primary infection often manifests as infectious mononucleosis (IM)
- IM usually self-limiting and is characterized by the following
  - Fever
  - Sore throat
  - Myalgias
  - Lymphadenopathy
  - Hepatosplenomegaly
Rare complications – hemolytic anemia and splenic rupture
Other serious symptoms may occur in extremes of age and among immunocompromised patients
- Thrombocytopenia
- Bulky adenopathy (cervical and axillary most common)
- Hemolytic anemia
- Hepatitis
- Meningitis
- Myocarditis
Disorders associated with EBV
- Infectious mononucleosis
- Endemic Burkitt lymphoma
  - Primarily in Africa; less common in developed countries
  - High grade B-cell lymphoma
  - >80% of nonendemic Burkitt lymphomas are EBV-negative
- Nasopharyngeal carcinoma (endemic in China)
  - Malignant nasopharyngeal tumor of the squamous epithelium
- Other cancers
  - EBV-associated Hodgkin lymphoma (mixed cellularity subtypes)
  - Tonsillar carcinoma
  - T-cell lymphomas (especially sinonasal T-cell lymphomas)
  - Thymoma
- X-linked lymphoproliferative syndrome (Duncan disease)
  - Often results in fatal, polyclonal B-cell proliferation
- Progressive lymphoproliferative diseases
  - Children with primary immunodeficiencies
  - Post-transplant lymphoproliferative disorders (PTLD)
  - Immunosuppressed or AIDS patients
- No good evidence to implicate EBV in chronic fatigue syndrome

Treatment

Treatment is supportive
- No contact sports for 6-8 weeks due to risk of splenomegaly and splenic rupture
- Steroids often used for severe symptoms

Indications for Testing

Acute disease, persistent pharyngitis and lymphadenopathy with negative strep testing

Laboratory Testing

CBC with differential – elevated white blood cells and atypical lymphocytes
Rapid strep test and/or culture – negative
Positive heterophile antibody (IgM antibodies not specific for EBV) – point of care testing (eg, Monospot)
- Heterophile test is often negative in children <5 years; may miss 50-70% of cases
- Antibodies develop after about day 5 of illness; do not test before 4-5 days
Diagnosis of acute disease due to EBV depends mostly on testing for an immune response to the virus
- Immune response during acute infection may be significantly delayed, especially in children and immunocompromised hosts
- Extensive work-up appropriate in markedly febrile patient with enlarged nodes and for whom prior testing was negative
- Initial antibody testing should include EBV anti-viral capsid antigen (VCA) IgM and IgG
- If testing is negative for EBV, consider serologies for cytomegalovirus (CMV) IgM, human herpesvirus 6 (HHV6) IgM and HIV testing
PCR, ELISA, probe testing – all usually reserved for immunocompromised patients or those with EBV-related tumors

Serologic features of EBV-associated diseases

Serologic Features of EBV-Associated Diseases
Condition	Anti-VCA Heterophile	Anti-VCA IgM	Anti-VCA IgG	Anti-EA EA-D	Anti-EA EA-R*	Anti-EBNA
Acute infectious mononucleosis	+	+	++	+	-	-
Convalescence	±	-	+	-	±	+
Past infection	-	-	+	-	-	+
Reactivation immunodeficiency	-	-	++	+	+	±
Burkitt lymphoma	-	-	+++	±	++	+
Nasopharyngeal carcinoma	-	-	+++	++	±	+
*EA-R antibody testing not recommended for mononucleosis assessment since the antibodies are not commonly present; however, EA-R antibody testing may be useful for diagnosing the African form of Burkitt lymphoma (rare in the U.S.)

Histology

Paraffin evaluation of tissue may be used for virus identification of EBV
Immunohistochemistry – stain for EBV latent membrane protein

Differential Diagnosis

Pharyngitis
- Streptococcal disease, group A
- Cytomegalovirus
- Human immunodeficiency virus
- N. gonorrhea
- Adenovirus, rhinovirus
- Toxoplasma gondii
- Human herpesvirus 6
- Herpes simplex virus-1
- Coxsackievirus A
Lymphadenopathy

EBV quantitative viral load testing may be indicated in transplant patients who develop primary mononucleosis or in new transplant patients
Inability to clear viral load after primary mononucleosis may be surrogate for PTLD
Increasing titers may signal reason to decrease immunosuppressive therapy to abort PTLD

Tests generally appear in the order most useful for common clinical situations

Test name: CBC with Platelet Count & Automated Differential

ARUP #: 0040003

Methodology: Automated Cell Count with Flow Cell Differential

Use:

Initial testing

Test name: Infectious Mononucleosis Slide Test by LA

ARUP #: 0050385

Methodology: Semi-Quantitative Latex Agglutination

Use:

Initial testing to confirm infectious mononucleosis or recent EBV infection (Monospot test)

Limitations:

Negative Monospot test is common in children and immunocompromised adults

Follow-up: If test results are negative but a strong clinical suspicion exists, repeat testing in 7-14 days

Test name: Epstein-Barr Virus Antibody to Viral Capsid Antigen, IgM

ARUP #: 0050240

Methodology: Semi-Quantitative Chemiluminescent Immunoassay

Use:

Clarify or confirm equivocal or negative Monospot test, especially in patients at risk for splenic rupture (contact sports)

Discriminate EBV from other IM-like diseases (eg, CMV, toxoplasmosis)

Follow-up:

Rule out other causes of lymphadenopathy by ordering antibody tests for toxoplasmosis and CMV

Repeat testing in 10-14 days may be helpful if results are equivocal

Test name: Epstein-Barr Virus Antibody to Viral Capsid Antigen, IgG

ARUP #: 0050235

Methodology: Semi-Quantitative Chemiluminescent Immunoassay

Use:

Clarify or confirm equivocal or negative Monospot test, especially in patients at risk for splenic rupture (contact sports)

Follow-up:

Rule out other causes of lymphadenopathy by ordering antibody tests for toxoplasmosis and CMV

Repeat testing in 10-14 days may be helpful if results are equivocal

Test name: Epstein-Barr Virus Antibody to Nuclear Antigen, IgG

ARUP #: 0050245

Methodology: Semi-Quantitative Chemiluminescent Immunoassay

Use:

Confirm previous infection with EBV

Follow-up:

Rule out other causes of lymphadenopathy by ordering antibody tests for toxoplasmosis and CMV

Repeat testing in 10-14 days may be helpful if results are equivocal

Test name: Epstein-Barr Virus by PCR

ARUP #: 0050246

Methodology: Qualitative Polymerase Chain Reaction

Use:

Detect EBV in cerebrospinal fluid and serum specimens

Diagnose EBV-related diseases in immunocompromised patients or patients with lymphoproliferative tumors

Do not use to confirm acute mononucleosis

Limitations:

Negative result does not rule out the presence of PCR inhibitors in patient specimen or EBV DNA in concentrations below assay detection

Test name: Epstein-Barr Virus, Quantitative PCR

ARUP #: 0051352

Methodology: Quantitative Polymerase Chain Reaction

Use:

Monitor disease (plasma, serum or CSF specimens)

Do not use to confirm acute mononucleosis

Limitations:

The limit of quantification for this DNA assay is 2.6 log copies/mL (390 copies/mL); if the assay DID NOT DETECT the virus, the test result will be reported as “<2.6 log copies/mL (<390 copies/mL)”

If the assay DETECTED the presence of the virus but was not able to accurately quantify the number of
copies, the test result will be reported as “Not Quantified"

Inhibition may also lead to underestimation of viral quantitation

Test name: Epstein-Barr Virus, Quantitative PCR, Whole Blood

ARUP #: 0051353

Methodology: Quantitative Polymerase Chain Reaction

Use:

Monitor disease (whole blood specimens)

Do not use to confirm acute mononucleosis

Limitations:

The limit of quantification for this DNA assay is 2.6 log copies/mL (390 copies/mL); if the assay DID NOT DETECT the virus, the test result will be reported as “<2.6 log copies/mL (<390 copies/mL)”

If the assay DETECTED the presence of the virus but was not able to accurately quantify the number of
copies, the test result will be reported as “Not Quantified"

Inhibition may also lead to underestimation of viral quantitation

Test name: Epstein-Barr Virus Antibody to Early D Antigen (EA-D), IgG

ARUP #: 0050225

Methodology: Semi-Quantitative Chemiluminescent Immunoassay

Use:

Confirm chronic active mononucleosis, post-transplant lymphoproliferative disease and nasopharyngeal carcinoma

This antibody test is more useful and appropriate than early antigen R for mononucleosis assessment

Follow-up:

Rule out other causes of lymphadenopathy by ordering antibody tests for toxoplasmosis and CMV

Repeat testing in 10-14 days may be helpful if results are equivocal

Test name: Epstein-Barr Virus Antibody to Viral Capsid Antigen, IgA

ARUP #: 0051626

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Use:

May be used in conjunction with Epstein-Barr Virus Antibody to Early D Antigen (EA-D), IgG to confirm chronic active mononucleosis, post-transplant lymphoproliferative disease, Burkitt lymphoma, nasopharyngeal carcinoma

Limitations:

IgA is variably seen; levels are not consistently elevated

Results vary in acute infectious mononucleosis, chronic active mononucleosis and post-transplant lymphoproliferative disease

Follow-up:

Rule out other causes of lymphadenopathy by ordering antibody tests for toxoplasmosis and CMV

Repeat testing in 10-14 days may be helpful if results are equivocal

Test name: Epstein-Barr Virus (EBV) By in situ Hybridization, Paraffin

ARUP #: 2002902

Methodology: In situ Hybridization

Use:

Virus identification of EBV

Test name: Cytomegalovirus Rapid Culture