Epstein-Barr Virus

 Usually represents liver involvement by infectious mononucleosis


image Elevated serum transaminase, alkaline phosphatase, and bilirubin levels

image Self limited in majority of cases


• EBV-associated lymphoproliferative disorders
image In immunocompromised individuals due to uncontrolled EBV replication

image Occurs in 1.0-2.8% of liver transplants

• Asymptomatic lifelong infection in > 90% of world adult population




Microscopic




• EBV hepatitis
image Diffuse sinusoidal lymphocytic infiltration in Indian file or string of beads pattern

image Mixed inflammatory cell infiltrates in portal tracts, consisting predominantly of lymphocytes

image Scattered large and irregular (atypical) lymphocytes in sinusoids and portal tracts

• Hepatic PTLD
image Morphology ranges from hepatitis-like to lymphoma


Ancillary Tests




• Detection of EBV early RNA (EBER) on tissue sections by in situ hybridization

image
Portal and Lobular Inflammation
Epstein-Barr virus (EBV) hepatitis is characterized by portal and lobular inflammation consisting predominantly of lymphocytes. Prominent sinusoidal lymphocytes can be appreciated even at this low power. There is also mild steatosis, unrelated to EBV infection.


image
Portal and Sinusoidal Lymphocytosis
This case of EBV hepatitis shows portal and lobular lymphocytic infiltrates. Note the string of beads linear pattern of lymphocytes in the sinusoids.

image
String of Beads Sinusoidal Infiltrates
A characteristic finding of EBV hepatitis is a diffuse sinusoidal lymphocytic infiltrate with an Indian file or string of beads pattern image. Occasional atypical lymphocytes image are noted. Hemophagocytosis, which can be seen in EBV hepatitis, is not observed in this case.

image
Portal Inflammation
Occasionally, EBV hepatitis features a florid portal infiltrate consisting of lymphocytes (some of which may be atypical) and histiocytes. Note the surrounding sinusoidal lymphocytosis.


TERMINOLOGY


Abbreviations




• Epstein-Barr virus (EBV)


Definitions




• Infection by EBV
image In liver, may cause either hepatitis or posttransplant lymphoproliferative disorder (PTLD)


ETIOLOGY/PATHOGENESIS


Infectious Agents




• Member of herpesvirus family (human herpesvirus-4)
image Double-stranded DNA virus

• Transmission via intimate contact, frequently with saliva of infected person
image Infection begins in oropharyngeal lymphoid tissues, particularly tonsils

image Viral envelop glycoprotein binds to CD21 (CR2) on B lymphocytes


CLINICAL ISSUES


Epidemiology




• New infection typically occurs during adolescence or young adulthood in developed countries
image Infectious mononucleosis 35-50% of time

• Typically occurs in 1st few years of life in developing countries with universal seroconversion by 3-4 years of age
image Usually asymptomatic

• Asymptomatic lifelong infection in > 90% of world adult population

• Dormant or latent in memory B lymphocytes
image Can be reactivated

image Commonly found in saliva


Presentation




• Infectious mononucleosis
image Incubation time of 4-6 weeks

image Fever, fatigue, malaise, sore throat, arthralgia, jaundice, lymphadenopathy, splenomegaly, and hepatomegaly

image Self-limited, usually resolves in 1-2 months

• EBV hepatitis
image Usually represents liver involvement by infectious mononucleosis

image Seen in immunocompetent and immunocompromised individuals

image Hepatomegaly seen in 10-15% of patients

image Jaundice seen in ∼ 5% of patients

image Elevated serum transaminase, alkaline phosphatase, and bilirubin levels

• EBV-associated lymphoproliferative disorders
image In immunocompromised individuals due to uncontrolled EBV replication
– Occurs in 1.0-2.8% of liver transplants

– Accounts for > 50% of all tumors in children and ∼ 15% of all tumors in adults following liver transplantation

– > 80% of cases occur in the first 2 years after transplantation

– Host origin in majority of cases, rarely donor origin

– Negative EBV status at transplantation and heavy immunosuppression for treatment of rejection are major risk factors


Laboratory Tests



Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Epstein-Barr Virus
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