HIV/AIDS Flashcards
What are gp120 and gp41? Where do they come from?
- Envelope proteins acquired through budding from host cell plasma membrane.
- Cleavage of gp160
What are the functions of gp120 and gp41
gp120: docking glycoprotein; attachment to host CD4+ T cells
gp41: transmembrane glycoprotein used for fusion and entry
What is gag (p24)? p17?
gag (p24)–capsid protein
p17- matrix protein
How does reverse transcriptase work?
Reverse transcriptase synthesizes dsDNA from RNA;
dsDNA integrates into the host genome
HIV binds to which receptors on T-cells? on macrophages?
Virus binds CCR5 (early) or CXCR4 (late) co-receptor and CD4 on T cells.
Binds CCR5 and CD4 on macrophages
Homozygous and heterozygous CCR5 mutations
Homozygous CCR5 mutation results in immunity from HIV
Heterozygous CCR5 mutation results in a slower course of the disease
HIV diagnosis:
ELISA and Western Blot assay
ELISA: sensitive, high-false positive rate with low threshold. It is a RULE OUT TEST
Western Blot: + results from ELISA are confirmed with Western Blot. It is specific, high-false negative rate, and a high threshold. It is a RULE IN TEST
What is the purpose of an HIV PCR test?
Determines viral load. The amount of viral RNA in the plasma. Higher loads are associated with poorer prognosis. Also used to monitor drug therapy
AIDS diagnoses: 3
- CD4+ cell count
ELISA/Western blot look for?
When are they falsely negative/positive?
What is the best way to test infants/babies?
They look for antibodies to viral proteins.
Often falsely negative in the first 1-2 months of HIV infection.
Often falsely positive initially in babies born to infected mothers. gp120 crosses the placenta.
PCR test for infants
Four stages of untreated HIV infection:
- Flu-like (acute)
- Feeling fine (latent)
- Falling CD4+
- Final crisis
Systemic disease of HIV+ patient:
Causes low grade fevers, cough, hepatosplenomegaly, and tongue ulcer.
Oval yeast cells within macrophages
CD4+
Histoplasma capsulatum
Dermatologic disease in HIV+ patient:
fluffy white, cottage-cheese lesions
pseudohyphae, oral if CD4+
Candida albicans
Dermatologic disease in HIV+ patient:
hairy leukoplakia
EBV
GI disease in HIV+ patient:
Chronic watery diarrhea
Acid-fast cysts in stool when CD4+
Cryptosporidium
Neurologic disease in HIV+ patient:
Brain abscesses
“ring-enhancing lesions”
CD4
Toxoplasma gondii
Neurologic disease in HIV+ patient:
Dementia
Other causes ruled out
HIV associated dementia
Neurologic disease in HIV+ patient:
Encephalopathy
Reactivation of latent virus causing demyelination
CD4
JC virus
Neurologic disease in HIV+ patient:
Meningitis
Yeast with narrow-based budding and large capsule.
There’s a big giveaway that I’m not giving
CD4
Cryptococcus neoformans
The give away was India Ink stain
Yeast causing meningitis in a AIDS patient should be enough
Neurologic disease in HIV+ patient:
Retinitis
May also hit esophagus
CD4
CMV
“SIGHT-o-megalovirus”
Oncologic disease in HIV+ patient:
Non-Hodgkins lymphoma
Often on oropharynx
May be associated with EBV
Oncologic disease in HIV+ patient:
Primary CNS lymphoma
Focal or multiple
Often associated with EBV
Squamous cell carincoma
Anus (MSM)
Cervix
HPV
Superficial neoplastic proliferation of vasculature
Lymphocytic infiltration on biopsy
Kaposi sarcoma (HHV-8)
Respiratory disease in HIV+ patient:
Interstitial pneumona
Biopsy shows “owl-eye inclusions”
CMV
Respiratory disease in HIV+ patient:
Pleuritic pain, hemoptysis, infiltrates on imaging
Shows sign of invasive infection
Aspergillus fumigatus
Respiratory disease in HIV+ patient:
“Ground-glass” appearance on imaging
CD4
Pneumocystis pneumonia
Respiratory disease in HIV+ patient:
Pneumonia
CD4 >*** 200
Strep. pneumoniae
Respiratory disease in HIV+ patient:
TB-like disease
CD4
MAC
