Epstein-Barr Virus

Epstein-Barr Virus Terry Kotrla, MS, MT(ASCP)BB

Diseases 

African or Burkitt’s Lymphoma – malignant B-cell neoplasm – presents as a rapidly growing tumour of the jaw, face or eye – grows very quickly, and without treatment most children die within a few months – Epstein-Barr virus (EBV) has been strongly implicated

African or Burkitt’s Lymphoma  

Although BL is a very rapidly growing tumour it responds well to treatment. Three pictures: before treatment, 3 days and 6 days after treatment

Nasopharyngeal Carcinoma     

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Endemic in South China, Africa, Arctic Eskimos This is a malignant tumour of the squamous epithelium of the nasopharynx. 100% contain EBV DNA Rates are less than 1 per 100,000 in most populations Nasopharyngeal carcinomas are found in association with reactivation of latent EpsteinBarr Virus. The exact mechanisms of association are unknown

B-Cell Lymphoma In most individuals infected with EBV, the virus is present in the B-cells, which are normally controlled by T-lymphocytes  When T-cell deficiency exists, one clone of EBVinfected B-lymphocytes escapes immune surveillance to become autonomously proliferating.  EBV induced B cell lymphomas are most prevalent in immunocompromised patients. 

Oral Hairy Cell Leukoplakia Viral infection of the oral cavity.  Indicator of HIV infection as well as of a person's lessening or weakening immunity 

Infectious Mononucleosis 

Downey cells may be present

Heterophile Antigens/Antibodies An antigen or antigenic determinant which is found in different tissues in more than one species.  These are antibodies found in one specie of animal (such as humans) which react against a component of another specie. 

Paul Bunnell Test 

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The original Paul-Bunnell test was a simple titration of sheep cell agglutinins but this procedure was subsequently modified in order to distinguish between sheep cell agglutinins formed in IM and the Forssman-type antibodies found in normal serum, serum sickness and in certain other conditions. Tissues rich in Forssman antigen (guinea pig kidney) absorb Forssman antibodies but do not affect the heterophil antibodies in IM. Heterophil antibodies are absorbed by beef cells, Forssman hapten is a glycolipid usually associated with a protein, the determinant being largely carbohydrate and therefore heat stable.

Davidsohn Differential 

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The principle behind the Paul-Bunnell-Davidsohn test is that the two types of sheep agglutinins are distinguished by titrating them before and after absorption with guinea pig kidney and ox cells. Patients serum containing antibodies due to IM is added to guinea pig kidney cells. These antibodies are not absorbed by the kidney cells. These antibodies then react with Beef (Ox) red blood cells which causes agglutination and is a positive test for IM. Patients serum containing Forssman antibodies are added to guinea pig kidney cells. Antibodies are absorbed by the kidney cells. These antibodies are then allowed to react with Beef red blood cells which does not cause agglutination. This is a positive test for Forssman antigens.

Davidsohn Differential

* To be considered absorbed there must be greater than a three tube difference between the presumptive titer and the differential titer.

Heterophil Antibody ------------------------

Kidney Extract ------------------

Beef Erythrocyte ---------------------

Infectious Mono

Not Absorbed

Absorbed

Forssman

Absorbed

Not Absorbed

Serum Sickness

Absorbed

Absorbed

Davidsohn Differential Advantages 

When properly performed, this test is specific for Infectious Mononucleosis and falsepositive results are rare.

Disadvantages 

Davidsohn Differential test is very time consuming and burdensome.