EpsteinBarr Virus Infection Infectious Mononucleosis

1
Epstein-Barr Virus Infection (Infectious
Mononucleosis)

• Pranee Sitaposa, M.D.
• Pediatric Infectious Diseases Fellow
• Queen Sirikit National Institute of Child Health
• Sep21, 2007

2
Epstein-Barr Virus History

• In 1889, German physician Pfeiffer
  
• fever
• lymphadenopathy
• malaise
• hepatosplenomegaly
• abdominal discomfort in adolescents and young
  adults
• In England, DrÜsenfieber, or glandular fever
• In the early 1900s
• numerous case descriptions of illnesses
  epidemiologically and clinically compatible with
  IM.

FEIGIN et al. Textbook of Pediatric Infectious
Diseases5th ed20041952-1957.
3
Epstein-Barr Virus History

• In 1920, Sprunt and Evans
• published cases of spontaneously resolving
  acute leukemia associated with blast-like
  cells in the blood
• In 1923, Downey and McKinlay
• detailed description of the lymphocyte
  morphology.
• In 1932, Paul and Bunnell
• Identified heterophile antibodies in serum during
  acute IM.

FEIGIN et al. Textbook of Pediatric Infectious
Diseases5th ed20041952-1957.
4
Epstein-Barr Virus History

• In 1958, Dennis Burkitt
• described 38 cases of round-cell sarcoma in
  children and adolescent living in Uganda, Africa.
  (Lymphoma)
• In 1964, Epstein
• described the first human tumor virus in a
  Burkitt lymphoma cell line by EM herpes simplex
  virus (HSV).
• human herpesvirus type 4
• In 1968, Henle
• reported the relationship between acute IM and
  EBV.
• Yale University
• showed EBV-transformed B-lymphoblastoid cell
  lines in tissue culture.

FEIGIN et al. Textbook of Pediatric Infectious
Diseases5th ed20041952-1957.
5
Virology Structure and Genome

• The structure of EBV is typical for a member
  of herpesvirus family
  Inner core of DNA surrounded by a nucleocapsid,
  tegument, and an
  envelope.
• The entire EBV genome short and long
  sections of unique sequences
  (Us and UL)

6
Molecular Biology Replication

• To infect cells, EBV uses a cell surface receptor
  (CR2,CD21) found primarily on B lymphocytes and
  nasopharyngeal epithelial cells.
• MHC class II protein functions as a cofactor for
  this virus-receptor interaction.
• After infection of epithelial cells, active
  replication occurs and leads to lysis and death
  of the cell.

7
Molecular Biology Replication

• Viral capsid antigens (VCAs) are the primary
  structure protiens in viral capsids and are found
  in replicating cells.
• EBV early antigens (EAs) consist of gt15 protiens
  codes by genes distributed throughout the genome.
• EBV nuclear antigen (EBNA) corresponds to six
  virally encoded protiens found in the nucleus of
  an EBV-infected cell.

8
Viral capsid antigens (VCAs)
9
Molecular Biology Latency

• Latently infected B cells are the primary
  reservoir of EBV in the body.
• gt100 gene products may be expressed during
  active viral replication, only 11 are
  expressed during viral latency.
• In this way, the virus limits cytotoxic T-cell
  recognition of EBV-infected cells.

10
Molecular Biology Transformation

• EBV generally transforms relatively mature B
  lymphocytes secreting a complete immunoglobulin
  product.
• EBV infect and transform B cells in earlier
  stages of development (e.g. pre-B cells and
  lymphoid precusors lacking immunoglobulin gene
  rearrangement)

11
Molecular Biology EBV Subtype

• 2 subtypes
  EBV-1 (type A) Western countries
• EBV-2 (type B) less virulence
• In immunocompromised persons co-infection
  both type 1 and type 2 strains
• No one subtype is responsible for specific
  lymphoproliferative diseases
  (geographic differences)

12
Immunopathogenesis IM

• In a normal host, both cellular and humoral
  immunity develops in response to EBV infection.
• Diagnosis of acute infection viral capsid and
  nuclear proteins.
• 2-7 wks after exposure, up to 20 of circulating
  B lymphocytes become infected during primary EBV
  infection.

13
Immunopathogenesis IM

• In acute stage, proliferating EBV-infected B
  cells are controlled principally by NK cells, CD4
  and CD8 cells.
• After T-cell response, number of EBV-infected B
  cells falls dramatically.
• Convalescence EBNA-3 protein.

14
Immunopathogenesis IM

• Primary EBV infection, like herpesviruses,
  is able to persist in a latent
  state in a human host throughout that persons
  lifetime.
• This ability indicates that EBV exerts some
  influence on the immune response to prevent its
  complete eradication.

15
Infectious Mononucleosis
NEJM343481-492.
16
Serum EBV antibodies
Nelson 17 edition, Textbook of Pediatrics
17
Serum Epstein-Barr Virus (EBV) Antibodies in EBV
Infection
AAP. Red book2006286-288.
18
EBV-associated tumors

• In normal hosts, cellular immune
  adequate for control and
  sequestration of
  EBV-infected cells.
• In cellular immune deficiency
  excess EBV-associated
  B-cell production
  -histologically pleomorphic
  (B-cell
  lymphoproliferative disease)
  -relatively uniform
  (monomorphic, B-cell lymphomas)

19
EBV-associated tumors

• Life-threatening EBV infections
  
• strong virus-induced T-cell proliferation
  cause autoaggressive activity producing
  hypogammaglobulinemia or other major organ
  dysfunctions
• multifactorial
• mixture of virology genetic
  environmental factors

20
EBV-associated lymphoproliferative diseases

• The most common form of non-Hodgkin lymphoma
  (NHL) is Burkitt lymphoma, which consists of
  sheets of small noncleaved cells that are
  histologically uniform.
• HD tissues presence of Reed-Sternberg cells
  admixed with lymphocytes and other reactive
  cells.
• Reed-Sternberg cells are large (15-45 µm),
  multinucleated cells probably derived from
  B or T cells.

21
EBV-associated lymphoproliferative diseases
Reed-Sternberg cells
22
Other EBV-associated diseases

• The hemophagocytic lymphohistiocytosis (HLH)
  typically include the bone marrow, spleen, liver,
  lymph nodes, skin and brain.
• In BM
• -hypocellularity
  -activated macrophages (histiocytes)
  are egulfing all bone marrow cellular
  element

23
Other EBV-associated diseases

• Three histopathologic categoies of epithelial
  tumors in nasopharynx, most common form is the
  undifferentiated variety, which is associated
  most strongly with EBV.
• Malignant cells consistently contain multiple
  copies of monoclonal EBV DNA within episomes and
  several EBV proteins are expressed.

24
Epidemiology Seroprevalence

• In the mid-1960s detection of antibodies to
  - VCA (long
  lasting, early in infection)
• - EA (short duration, early in infection)
• EBV-VCA antibodies 100 in BL patients
  85 in normal adults
• 80-95 of adults have serologic evidence, most
  infections occuring during infancy and children.

25
Primary EBV infection Seroprevalence

• In developing countries
  -80-100 of children becoming
  infected by 3-6 yrs of age
• -clinically silent or mild disease.
• In developed countries
  -occurs later in life, 10-30 years of age
  -induce clinically
  mononucleosis syndrome (U.S.college students
  50-75 associated with primary EBV
  infection)

Hickey SM et al. Pediatr Clin North
Am. Dec 199744(6)1541-56.
26
Epidemiology Incidence

• Population-based studies 50-100 100,000
  population.
• Highest incidence rates 15-19 years.
• No seasonal predilection.
• Higher rate in persons of white race than in
  other ethnic groups.

27
Epidemiology viral shedding

• In 1971, Chang and Golden identified a
  leukocyte-transforming agent in oropharyngeal
  secretions.
• Studies in healthy populations indicating
• 1) most children and adults with acute IM shed
  EBV in their oropharynx
• 2) 6 20 of general population shed EBV in
  the oropharynx
• 3) oropharyngeal shedding may be intermittent
  or continuous
• 4) high concentrations of EBV in oropharyngeal
  secretions are associated with high
  concentrations of EBV in B lymphocytes in
  peripheral blood but not with
  concentrations of EBV-specific serum antibodies

28
Epidemiology Transmission

• Incubation period 30 50 days.
• (shorter in young children)
• Oral secretion major
  role but occur slowly
• Blood products,Transplanted organs
  less commonly than CMV
• Intrauterine infrequently if
  infected no adverse fetal outcomes and
  no viral transmission to the fetus.

Fleisher, et al. J. Pediatr.9816-19, 1981.
29
Clinical Syndromes Associated with EBV Infection

• Silent, nonspecific infections in children
• - prolonged low-grade fever lymphadenopathy
• - cough
• - rhinorrhea
• - pharyngitis
• Infectious mononucleosis (IM)
• - prodrome
• 2 5 days malaise, fatigue, possibly fever
• - acute phase
• fever (last 45 wks), lymphadenopathy (24
  wks), tonsillopharyngitis, splenomegaly,
  hepatomegaly, rash, abdominal pain, eyelid edema
  15
• - resolution phase organomegaly may persist
  13 m

30
IM Pathophysiology

• Reservoir of EBV Humans only.
• EBV founds in the saliva for the first 12-18
  months after acquisition.
• Viral replication
• lymphoreticular system
• liver
• spleen
• B lymphocytes in peripheral blood.

31
IM Pathophysiology

• Host immune response to the viral infection
• atypical lymphocytes.
• After acute EBV infection, latently infected
  lymphocytes and epithelial cells persist and are
  immortalized.
• During latent infection, the virus is present in
  the lymphocytes and oropharyngeal epithelial
  cells as episomes in the nucleus.

32
IM Pathophysiology

• A low rate of viral reactivation occurs within
  the population of latently infected cells.
• Primary source of new virus in latently infection
  
• Epithelial cells.
• Virus can be isolated from oral secretions of
  20-30 of healthy latently infected individuals
  at anytime.

33
IM Pathophysiology
NEJM343481-492.
34
Infectious Mononucleosis

• In Africa, the virus is associated with endemic
  Burkitt lymphoma.
• NP cacinoma numerous EBV episomes
• Most common CA in adult men in southern China
• North American Inuits
• North African whites.

35
Infectious Mononucleosis
36
Infectious Mononucleosis

• No racial and sexual difference.
• The peak incidence occurs 2 years earlier in
  females.
• Report in middle-aged and elderly adults
• heterophile antibody negative.
• Most clinical symptoms are a consequence of T
  cell proliferation and organ infiltration.

37
Infectious Mononucleosis

• Acute infectious mononucleosis
• fatique and malaise 1-2 wks
• sore throat, pharyngitis
• retro-orbital headache
• fever
• myalgia
• nausea
• abdominal pain
• generalized lymphadenopahy
• hepatosplenomegaly

38
Infectious Mononucleosis

• Pharyngitis is the most consistent physical
  finding.
• 1/3 of patients exudative pharyngitis.
• 25-60 of patients petechiae at the junction
  of the hard and soft palates.
• Tonsillar enlargement can be massive, and
  occasionally it causes airway obstruction.

39
Infectious Mononucleosis

• Lymphadenopathy 90
• symmetrical enlargement.
• mildly tender to palpation and not fix.
• posterior cervical lymph nodes.
• anterior cervical and submandibular nodes.
• axillary and inguinal nodes.
• Enlarged epitrochlear nodes are very suggestive
  of infectious mononucleosis.

40
Infectious Mononucleosis

• Hepatomegaly 60
• jaundice is rare.
• Percussion tenderness over the liver is common.
• Splenomegaly 50
• palpable 2-3 cm below the left costal margin and
  may be tender.
• rapidly over the first week of symptoms, usually
  decreasing in size over the next 7-10 days.
• spleen can rupture from relatively minor trauma
  or even spontaneously.

41
Infectious Mononucleosis

• Maculopapular rash 15
• usually faint, widely scattered, and erythematous
  
• occurs in 3-15 of patients and is more common in
  young children.
• 80 of patients, treatment with amoxicillin or
  ampicillin is associated with rash
• Circulating immunoglobulin G (IgG) and
  immunoglobulin M (IgM) antibodies to ampicillin
  are demonstrable.

42
Infectious Mononucleosis
IM with rash after treatment with amoxicillin or
ampicillin
NEJM343481-492.
43
Infectious Mononucleosis

• Eyelid edema 15
• may be present, especially in the first week
• Children younger than 4 years more commonly
• splenomegaly or hepatomegaly
• rash
• symptoms of an upper respiratory tract infection

44
Clinical manifestation of IM
in children and adults

• Frequency ()
• Sign or symptom Age lt 4 yr Age 4 16
  yr Adults (range)
• Lymphadenopathy 94 95 93 100
• Fever 92 100 63 100
• Sore throat or 67 75 70 91
• tonsillopharyngitis
• Exudative 45 59 40 74
• tonsillopharyngitis
• Splenomegaly 82 53 32 51
• Hepatomegaly 63 30 6 24
• Cough or rhinitis 51 15 5 31
• Rash 34 17 0 15
• Abdominal pain or 17 0 2 14
• discomfort
• Eyelid edema 14 14 5 34

Sumaya, et al. J Infect Dis.131403-408,1975.
45
Infectious Mononucleosis
NEJM343481-492.
46
Infectious Mononucleosis
Exudative pharyngotonsillitis
47
Infectious Mononucleosis
Hepatosplenomegaly
Cervical lymphadnopathy
48
Infectious Mononucleosis Cause

• EBV 90 of acute IM
• Etiology of most EBV-negative IM unknown
• Other Herpesviruses
• Cytomegalovirus (CMV)
• herpes simplex 1 and simplex 2
• human herpesvirus 6
• Other viruses
• adenovirus
• hepatitis A, hepatitis B, or hepatitis C
• rubella
• primary human immunodeficiency virus in
  adolescents or young adults.

49
Infectious Mononucleosis Lab

• The 3 classic criteria for laboratory
  confirmation
• 1 lymphocytosis
• 2 the presence of at least 10 atypical
  lymphocytes on peripheral smear
• 3 a positive serologic test for Epstein-Barr
  virus (EBV).

50
Infectious Mononucleosis Lab

• Complete blood count
• 40-70, Leukocytosis
  (WBC 10,000-20,000 cells per
  cm3)
• By the second week of illness, approximately
  10 have a WBC count gt 25,000 per
  cm3.
• 80-90 of patients have lymphocytosis,
  with greater than 50 lymphocytes.
  Lymphocytosis is greatest during 2-3 weeks of
  illness and lasts for 2-6 weeks.
• 20-40 of the lymphocytes atypical
  lymphocytes gt 10 Downey types
• 25-50, Mild thrombocytopenia

51
Infectious Mononucleosis
atypical lymphocytes Downey types
52
Infectious Mononucleosis Lab

• Liver function tests
• 80-100 of patients elevated LFT
• Alkaline phosphatase, AST and bilirubin
  peak 5-14 days after onset
• GGT peaks at 1-3 weeks. Occasionally, GGT remains
  mildly elevated for up to 12 months
• 95 of patients elevated LDH
• most liver function test results are normal by
  3 months.

53
Infectious Mononucleosis Lab

• Heterophile antibodies
• 50 in first week of illness
• 60-90 in the second or third weeks
• begins to decline during the fourth or fifth week
  and often is less than 140 by 2-3 months after
  symptom onset
• 20 of patients have positive titers 1-2 years
  after acquisition
• children lt 2 years 10-30
• children 2-4 years 50-75

54
Infectious Mononucleosis Lab

• EBV serology
• EAs (early antigens) early in the lytic
  cycle
• VCA (Viral capsid antigen) and membrane antigens
  late in the lytic cycle
• EBNA (Epstein-Barr nuclear antigen) latent
  infection
• Antibodies to membrane antigens usually are
  not measured

55
Infectious Mononucleosis Lab

• EA/D (diffuse-staining component of EA) 80
• EA/R (restricted component of early antigens)
• measurable in children younger than 4 years with
  primary EBV infection or in asymptomatic
  infection.
• nasopharyngeal carcinoma
• antibodies to EA/R are high in individuals with
  EBV-associated Burkitt lymphoma.
• immunocompromised patient
• persistent or reactivated EBV infections often
  have high antibody levels to EA/D or EA/R.

56
Infectious Mononucleosis Lab

• Time course of antibody production
• EA is rising at symptom onset rise for 3-4
  weeks, then quickly decline to undetectable
  levels by 3-4 months, although low levels may be
  detected intermittently for years.
• VCA-IgM usually is measurable at symptom onset,
  peaks at 2-3 weeks, then declines and
  unmeasurable by 3-4 months.
• VCA-IgG rises shortly after symptom onset, peaks
  at 2-3 months, then drops slightly but persists
  for life.
• EBNA convalescence and remain present for life.

57
IM Treatment

• Medical Care
• self-limited illness not require specific
  therapy.
• Inpatient therapy of medical and surgical
  complications may be required.
• Acyclovir (10 mg/kg/dose IV q8h for 7-10 d)
• inhibit viral shedding from the oropharynx
• clincal course is not significantly
• IVIG (400 mg/kg/d IV for 2-5 d)
• immune thrombocytopenia associated with

Andersson J et al. J Infect Dis. Feb
1986153(2)283-90. Cyran EM et al. Am J
Hematol. Oct 199138(2)124-9. 
58
IM Treatment

• Medical Care
• Short-course corticosteroids
• prednisolone (1 mg/kg/d, max 60 mg/d for 7 d
  
• and tapered over another 7 d)
• Marked tonsillar inflammation with impending
  airway obstruction
• Massive splenomegaly
• Myocarditis
• Hemolytic anemia
• Hemophagocytic syndrome
• Seizure and meningitis
• Surgical Care
• Splenic rupture.

AAP. Red book2006286-288. Nelson. Textbook of
Pediatrics17th ed977-981.
59
Infectious Mononucleosis

• Activity
• depends on severity of the patient's symptoms.
• Extreme fatigue bed rest for 1-2 weeks.
• Malaise may persist for 2-3 months.
• Patients should not participate in contact
  sports or heavy lifting for at least 2-3
  weeks
• some authors recommend avoiding activities that
  may cause splenic trauma for 2 months.

60
IM Complication

• Hepatitis gt 90 of patients
• LFT lt 2-3 times of NUL in the second and third
  weeks of illness
• 45 of patients elevated bilirubin, but
  jaundice occurs in only 5. Mild thrombocytopenia
  occurs in approximately 50 of patients with
  infectious mononucleosis.
• Platelet count nadir approximately 1 week after
  symptom onset (100,000-140,000/cm3. ), then
  gradually improves over the next 3-4 weeks. Mild
  thrombocytopenia occurs in approximately 50 of
  patients with infectious mononucleosis.

61
IM Complications

• Hemolytic anemia
• 0.5-3, associated with cold-reactive antibodies,
  anti-I antibodies, and with autoantibodies to
  triphosphate isomerase
• mild and is most significant during the second
  and third weeks of symptoms.
• Upper airway obstruction
• 0.1-1, due to hypertrophy of tonsils and other
  lymph nodes of Waldeyer ring
• treatment with corticosteroids may be beneficial

62
IM Complications

• Splenic rupture 0.1-0.2
• Spontaneous or history of some antecedent trauma.
  
• occur during the second and third weeks.
• mild-to-severe abdominal pain below the left
  costal margin, sometimes with radiation to the
  left shoulder and supraclavicular area.
• Massive bleeding Shock

63
IM Complications

• Hematologic complications
• hemophagocytic syndrome.
• Immune thrombocytopenic purpura occurs and may
  evolve to aplastic anemia.
• accelerate hemolytic anemia in congenital
  spherocytosis or hereditary elliptocytosis.
• Disseminated intravascular coagulation associated
  with hepatic necrosis has occurred.

64
IM Complications

• Neurologic complications lt 1
• during the first 2 weeks.
• negative for the heterophile antibody.
• Severe (fatal), complete recovery
• aseptic meningitis, acute viral encephalitis,
  coma, meningitis, and meningoencephalopathy.
• Hypoglossal nerve palsy, Bell palsy, hearing
  loss, brachial plexus neuropathy,
  multiple cranial nerve palsies, Guillain-Barré
  syndrome, autonomic neuropathy, gastrointestinal
  dysfunction secondary to selective cholinergic
  dysautonomia, acute cerebellar ataxia, transverse
  myelitis.

65
IM Complications

• Cardiac and pulmonary complications
• rare
• chronic interstitial pneumonitis.
• myocarditis and pericarditis.

66
IM Complications

• Autoimmune complications
• Autoimmune diseases and Reye syndrome have been
  associated with EBV infection.
• Infectious mononucleosis stimulates production of
  many antibodies not directed against EBV. These
  include autoantibodies, anti-I antibodies, cold
  hemolysins, antinuclear antibodies, rheumatoid
  factors, cryoglobulins, and circulating immune
  complexes. These antibodies may precipitate
  autoimmune syndromes.

67
IM Complications

• Miscellaneous complications
• Renal disorders immune deposit nephritis, renal
  failure, paroxysmal nocturnal hemoglobinuria.
• After cardiac bypass or transfusion, an
  infectious mononucleosislike syndrome primary
  CMV infection gt EBV.
• A syndrome of chronic fatigue, myalgias, sore
  throat, and mild cognitive dysfunction occurring
  primarily in young adult females initially was
  attributed to EBV. Current data suggest that EBV
  is not the etiologic agent.

68
IM Prognosis

• Immunocompetent full recovery in several
  months.
• The common hematologic and hepatic complications
  resolve in 2-3 months.
• Neurologic complications
• Children resolve quickly
• Adults neurological deficits
• All individuals develop latent infection
• asymptomatic.

69
IM Prevention

• Isolation is not required low transmission.
• Avoid contact with saliva.
• Do not kiss children on the mouth.
• Maintain clean conditions day care, avoid
  sharing toys.
• EBV can be transmitted by blood transfusion and
  by bone marrow transplantation.
• Vaccine development is proceeding, although the
  role of a vaccine is unclear.

FEIGIN et al. Textbook of Pediatric Infectious
Diseases5th ed20041952-1957.
70
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