Herpesvirus and HIV Pathophysiology

Question 1

Traube’s space

Answer 1

lower left lung where you percuss the spleen to see splenomegaly

Question 2

CBC presentation of EBV

Answer 2

*atypical lymphocytosis: reactive cytotoxic T lymphocytes

Question 3

heterophile (monospot) test

Answer 3

-shows the ability of the patient’s serum to agglutinate horse red blood cells
-used as a test for infectious mononucleosis
*a positive test is sufficient to CONFIRM a diagnosis
*a negative test does NOT exclude mono

Question 4

EBV pathophysiology

Answer 4

*EBV induces a proliferation of B lymphocytes in the lymphoid tissue, causing B cells that resemble malignant lymphocytes on histology

Question 5

what cell does EBV infect

Answer 5

infects B lymphocytes (resides in a latent state for the remainder of the patient’s life)
*in TISSUES (tonsils and lymph nodes - CD20 positive B cells)

Question 6

epidemiology of EBV

Answer 6

*one of the most common viruses in humans
*transmitted by saliva

Question 7

pathogenesis of EBV

Answer 7

1. initially infects oropharyngeal epithelial cells
2. spreads to underlying lymphoid tissue
3. mature B cells are infected; some are lytic and some are latent

Question 8

EBV transforming latency genes

Answer 8

1. EBNA 1 and 2
2. LMP1
3. vIL-10

Question 9

EBNA 1 and 2 (Epstein-Barr nuclear antigens)

Answer 9

*a transforming latency gene of EBV
*binds EBV genome to host cell chromosomes
**promotes B cell REPLICATION (turns on protein transcription that drive cell cycling)
*we can detect antibodies against EBNA

Question 10

latent membrane protein 1 (LMP1)

Answer 10

*a transforming latency gene of EBV
*drives B cell ACTIVATION
*PREVENTS APOPTOSIS (immortalizes the B cells) by activating Bcl-2

Question 11

vIL-10 (homologue of IL-10)

Answer 11

*a transforming latency gene of EBV
*SUPPRESSES CELL-MEDIATED RESPONSES (inhibits macrophages and dendritic cells and suppresses antiviral T cell responses)

Question 12

EBV infection results in?

Answer 12

BOTH HUMORAL AND CELLULAR RESPONSE
1. humoral response - secretes antibodies with many specificities
2. T cell-response - CD8+ cytotoxic T cells and NK cells in peripheral blood

Question 13

EBV serology

Answer 13

1. IgM antibody to Viral Capsid Antigen (IgM-VCA) increases FIRST
2. IgG-VCA produced later
3. EBNA persists and indicates latency

Question 14

viral latency definition

Answer 14

persistence of viral genomes in cells that do NOT produce infectious virus

Question 15

CMV clinical features

Answer 15

*immunocompetent people: asymptomatic or mono-like infection
*neonates/immunocompromised: devastating systemic infections (CMV pneumonia, CMV colitis)

Question 16

EBV reactivation

Answer 16

*Burkitt lymphoma
*Nasopharyngeal malignancy

Question 17

HIV labs

Answer 17

*reduced CD4+ cell count
*p24 ELISA test positive = HIV confirmatory test

Question 18

Pneumocystis jirovecii pneumonia

Answer 18

opportunistic fungal infection, presents in HIV patients (and other immunodeficient patients)
*treatment with TMP-sulfa

Question 19

AIDS and neurologic impairment

Answer 19

several different things can cause altered mental status in AIDS patients:
1. opportunistic diseases
2. neoplastic diseases
3. primary HIV-associated syndromes

Question 20

common diarrhea-producing pathogens in AIDS

Answer 20

*mycobacterium avium-intracellulare
*cryptosporidium or isosporidium
*CMV

Question 21

Kaposi sarcoma

Answer 21

*associated with HHV-8
*purple-red vascular lesions on the skin
*commonly occurs in immuno-compromised patients

Question 22

HIV overview

Answer 22

retrovirus characterized by destruction of CD4+ T cells, leading to profound immunosuppression that leads to:
-opportunistic infections
-secondary neoplasms
-neurologic manifestations

Question 23

HIV transmission

Answer 23

1. sexual contact
2. parenteral inoculation (sharing needles)
3. mother-to-infant

Question 24

important envelope proteins in HIV

Answer 24

1. gp120 (binds to CD4+ T cells)
2. gp41 (allows envelope to fuse to CD4 T cell)

Question 25

important core protein in HIV

Answer 25

p24 (major capsid protein)
**used to DIAGNOSE HIV

Question 26

acute viral syndrome in HIV

Answer 26

viremia dissemination and development of host immune response
-infection of CD4+ T cells
*death of many infected cells

Question 27

chronic phase (clinical latency) of HIV

Answer 27

over a period of years, continuous cycling of virus infection, T cell death, and new infection leads to STEADY DECLINE IN # of CD4+ T cells
*usually asymptomatic

Question 28

clinical AIDS

Answer 28

breakdown of host defense
serious opportunistic infections, secondary neoplasms, or clinical neurologic disease