HIV Flashcards
(28 cards)
what does the HIV genome look like?
two molecules of single stranded RNA (positive sense)
what are the three structural proteins coded for by the HIV genome?
env (gp160 which becomes 120 and 41), pol (reverse transcriptase, aspartate protease and integrase) and gag (p24, a capsid protein)
what form of DNA is made from RNA via reverse transcriptase
double stranded DNA
during early infection HIV binds the ______ receptor on CD4+ cells and during late infection HIV binds the _______ receptor on CD4+ cells
CCR5 receptor during early infection
CXCR4 receptor during late infection
what receptors does HIV bind on macrophages
CCR5 and CD4
what does having CCR5 mutations do (homozygous and heterozygous)?
homozygous= immunity
heterozygous=slower course of disease
how is HIV diagnosed?
ELISA test is done to rule out (high sensitivity)
Western blot done to confirm (high specificity)
(these are both antibody tests)
how is AIDS diagnosed?
- CD4 count of less than or equal to 200/mm3
- HIV with AIDS-associated illness (i.e. PCP)
- CD4/CD8 ratio <1.5
when do you see false positives and false negatives?
false positives are seen in babies born to infected mothers (anti-gp120 crosses placenta)
false negatives are seen 1-2 months post infection
what are the four stages of HIV infection
- flu-like symptoms
- feeling fine (latency)
- falling count
- final crisis
where does the virus replicate during the latent phase?
lymph nodes
at what CD4+ count does a patient with HIV become immunocompromised?
CD4+ count less than or equal to 400/mm3
what does histoplasma cause in an HIV immunocompromised patient? at what CD4+ counts?
low-grade fever, cough, hepatosplenomegaly, tongue ulcer
this occurs in patients with CD4 counts less than 100
what does histoplasma look like on a slide?
oval yeast within macrophage
Your HIV patient has fluffy, white cottage cheese-looking lesions. What pathogen causes this? Where would these lesions be found in a patient <100 CD4 count?
C. albicans
these lesions are found in the mouth of a patient with CD4 <100 cells
what does bartonella henselae cause in HIV infected patients? what is found on biopsy?
bacillary angiomatosis (a superficial vascular proliferation) on biopsy neutrophilic inflammation is seen
what bug commonly causes diarrhea in HIV infected patients? what kind of diarrhea is it? what is seen in the stool?
cryptosporidium; watery diarrhea
acid fast oocysts seen in stool
which virus when reactivated leads to encephalopathy due to demyelination?
JC virus, which leads to progressive multifocal leukoencephalopathy (inflammation of white matter)
which microbe causes ring-enhancing abscesses in the brain?
toxoplasma gondii
what neurologic pathologies are associated with HIV?
meningitis (cryptococcus neoformans), brain abscess (toxoplasma), encephalitis (JC virus), HIV dementia, retinitis (CMV)
what pathogen causes retinitis in HIV patients (CD4 <50cells/mm3)? what does the retinitis appear as on fundoscopic exam?
cytomegalovirus (CMV);
cotton-wool spots are seen on fundoscopic exam
what is seen on a biopsy of Kaposi’s sarcoma? what pathogen is associated with Kaposi’s sarcoma?
lymphocytic inflammation
HHV-8
where is hairy leukoplakia usually seen and what virus is it associated with?
usually seen on the lateral tongue and associated with EBV
what three neoplasms are associated with EBV infection in HIV patients?
hairy leukoplakia (on lateral tongue); non-Hodgkin’s lymphoma (large cell type, in the oropharynx); focal or multiple primary CNS lymphomas
