HIV Flashcards
Which is more prevalent? HIV 1 or HIV2
HIV-1
Which HIV-1 Group is the most common globally? (M/ N/ O/ P)
M
Which subtype or clade of HIV is most common in US & EU?
B
Top 3 causes of HIV
Blood transfusions, Anal Sex: Receptive partner’s risk (w/ ejaculation), Needle sharing (injection drug use)
HIV risk factors
- Viral load
- Sexual behavior
- Sexually transmitted infections
- Lack of circumcision
- Genetic background
Hallmarks of HIV
- High replication rate
- High error rate
- Plastic envelope
HIV Cell Cycle
Step 1: HIV attaches to a CD4 receptor on the cell membrane of the host cell
Step 2: HIV fuses with the cell membrane and releases its contents into the host cell
Step 3: HIV’s protein coat degrades. HIV’s RNA and reversible transcriptase are released into cell cytoplasm.
Step 4: Reverse transcriptase rewrites HIV’s single - stranded RNA as HIV’s double stranded DNA.
Step 5: HIV’s DNA enters the host cell’s nucleus and is then inserted into the DNA of a host cell chromosome
Step 6: Many copies of single-stranded HIV RNA are made. They direct the synthesis of HIV’s proteins
Step 7: HIV RNA and proteins gather at the cell membrane and leave the host cell as an immature virus
Step 8: HIV RNA and proteins are reassembled to form a mature virus which goes on to infect other cells
Chronic T cell activation leads to:
*Death of infected cells (cytopathic effect of virus)* due to viral replication in infected CD4+ T cells
*Activation-induced cell death (apoptosis)* due to activation of uninfected CD4+ T cells
*Killing of infected cells by virus-specific cytotoxic T lymphocytes* due to expression of HIV peptides on infected CD4+ T cells
CD4 cells:
- % turnover daily
- relationship with mortality
6-7%
Decreased CD4 cells = increased probability of AIDS or death
What is critical in monitoring virologic response to anti-retroviral therapy?
Viral load
Viral load:
- half life inside & outside cell
- % viral burden turned over daily
- 24 hour inside & 6 hours outside
- 30%
Acute HIV Infection:
- How long does it take for this to occur after HIV exposure?
- How long does this phase last?
- Symptoms strongest? Time frame
- Antibody test results: Time frame
- 2-3+ weeks
- 1-3 months
- 2-3+ weeks
- Negative: 2-3 weeks, Positive: rest of acute HIV infection phase
Main Symptoms of HIV infection:
- Fever
- Weight loss
- Pharyngitis
- Sores and thrush in mouth
- Sores in esophagus
- Myalgia
- Liver & spleen enlargement
- Malaise
- Headache
- Neuropathy
- Lymphadenopathy
- Rash
- N/V
Chronic/ Latent HIV infection: Asymptomatic & Symptomatic [Characteristics]
Asymptomatic:
- Persistent generalized lymphadenopathy (Symmetrical, modestly enlarged, cervical, submandibular, occipital, axillary)
- Further evaluation not necessary
Symptomatic:
- Occurs especially as CD4 count decreases
- Skin & mucous membrane involvement
- Thrush, skin & soft tissue infection, rashes
Patho of progression:
(a) Types
(b) Compartmentalization
(c) Cell affected
(a) Types: Rapid progressors, long-term non-progressors, elite controllers
(b) Gut associated lymphoid tissue, brain tissue, kidneys, liver
(c)
- T-cell homeostasis affected
- Disrupted lymph-node architecture
