HIV (Human Immunodeficiency Virus) & AIDS (Acquired Immunodeficiency Syndrome) Flashcards
HIV leads to what
immunodeficiency
virus incorporates self into host cells to replicate
cmplx of HIV infection
AIDS
what virus targets the immune system for HIV
retrovirus
how does retrovirus impact DNA
- Usually DNA transcribes into RNA and that forms proteins
- These viruses take RNA and put it into the DNA of the host (work backwards)
- results in profound immunosuppression (develop infection & CA easily)
etiology & transmission
- sexually transmitted
- maternal
how is it sexually transmitted
semen contains virus & virus carried in blood
how is it transmitted maternally
- in utero
- labor & delivery (severed blood vessel & baby contacts blood)
- lactation (through breast milk)
3 stages of HIV
1) primary infection
2) latent period
3) overt AIDS
(1) primary infection duration
weeks - months
(1) primary infection
- seroconversion
- high viral load
- dec CD4 count
pt tests negative for HIV in what stage
primary infection (window period – time it takes Abx to form)
seroconversion
formation of Abs
(2) latent period
- asympt for years
- lymphatic tissue damage
- recurrent respiratory infections
why do recurrent respiratory infections occur in latent period (2)
b/c most microbes & viruses enter via inhalation
(3) overt AIDS
- ~10 yr (60-70%): typical progressors
- ~5 yrs: rapid progressors
- ~15 yrs: slow progressors
- long-term non-progressors (2-5%): do not develop AIDS
- CD4 count below 200 & have an opportunistic infection = AIDS
patho
- targets T helper cells (CD4)
- also targets macrophages & B cells
- destroys immune system (new infections occur d/t latent pathogens)
- many organs affected
if T helper cells (CD4) are damaged, what happens
cytokines not generated for immune cells to communicate with e/o –> immune system compromised
B cells
Responsible for Ab formation, if these are targeted, then Ab formation inhibited
Dx
- clinicl presentation
- ELISA (Ab test) –> Es-linked immunosorbant assay
- western blot assay
- PCR (polymerase chain rxn)
- CD4 counts & viral loads (inversely proportional)
- quick tests (rapid serum & saliva tests)
ELISA (Ab test)
Body’s production of Abs measured against entire virus using an enzymatic method
- if test positive, they confirm w/ Western blot assay
Western blot assay
Abs produced to a specific part of HIV virus (more specific test)
PCR (Polymerase Chain Reaction)
Amplifies genetic material and measures viral particle itself (rarely used)
CD4 counts & viral loads
Surface proteins on T helper cells –> CD4 counts measure the number of T helper cells
(if this is low, then the viral load must be high and vice versa)
quick tests: new rapid serum & saliva tests
indicates pt might be positive, more specific tests used
- P24 antigen
P24 antigen
protein found in the viral core and makes its appearance early (between time of infection and seroconversion, when antibodies are detectable)
mnfts
- extensive, involves many body systems
- recurrent resp infections
- GI infections
- NS: dementia, encephalopathy
- opportunistic CA
why do recurrent resp infections occur
defense is compromised d/t infection impacting resp tract (ex. TB & pneumonia)
why do GI infections occur
from normal flora & ingested microbes (in food)
ex. diarrhea, gastroenteritis, etc.
why does dementia & encephalopathy occur
impaired CNS Fx d/t various infections & virus presence
opportunistic CA
Malignant cells in early stage controlled by immune system
- Kaposi’s sarcoma
- cervical CA
- Non-Hodgekin’s lymphoma
Kaposi’s sarcoma
mesenchyme origin (non-epithelial) –> arises in endothelial cells (lining blood vessels), forms malignant lesions (appear in skin, mucosa of mouth, lymph nodes)
cervical CA cause
d/t HPV infection (compromised defences)
Tx
- incurable
- HAART (Highly-Active Anti-Retroviral Therapy)
- polypharmacy
what drugs used
antiviral agents (at least 3) – each target diff steps
what antivirals used
- reverse transcriptase inhibitors
- protease inhibitors
- entry inhibitors
- integrase inhibitors
reverse transcriptase inhibitors
inhibit the viral RNA replicating into DNA, and the multiplication of the virus
protease inhibitors
inhibits the enzyme that breaks down proteins –> proteases break up polypeptides in host cells
entry inhibitors
inhibit entry into the host cell
if the virus cannot get into the cell then it cannot damage it
integrase inhibitors
enzyme inhibited –> prevents the viral particle from integrating its RNA into the host cell’s DNA
functions of antivirals
A) Prevents virus from entering host cell
B) Presents virus from integrating RNA into DNA
C) Prevents virus from dividing
