HIV Flashcards
What are the major cellular targets of the HIV virus
CD4 T cells and macrophages (and others eg. monocytes, dendritic cells, eosinophils, microglial cells)
What are the host cell membrane receptors that the HIV virus binds to (with gp421 and gp120)
CCR5 (more commonly, has selective transmission advantages) and CXCR4 (less commonly)
Describe the natural progression of plasma HIV viral load and CD4 count inuntreated HIV
- Initially the HIV viral load will shoot up and peak and then start to come down within the first 4-8 weeks (CD4 count will plummet down at the end of this period)
- HIV RNA/viral load will then reach a steady state (viral set point) as the CD4 count starts topick up at timeof seroconversion when the body begins to mount an immune response
- There will then be an asymptomatic period of up to 19 years with steady HIV RNA but slowly decreasing CD4 count
- As CD4 count declines will then become symptomatic for 3-5 years –> death
Describe some factors affecting HIV disease progression
Viral factors
- HIV1 progresses faster than HIV-2
- HIV subtype (eg group M)
- Co-receptor: CXCR4 faster than CCR5
Immunological factors
- Virus specific Cd8 cytotoxic T cells
- CertainHLA types
- CCR5-delat-32 mutation
Co-infections
- TB, syphilis, helminthic
Extremes of age
- Due to impaired thymic function
True or false, CD4 count is a surrogate marker of immunological damage due to viraemia and indicates risk of opportunistic disease
True
Describe the HIV OIs:
Neoplasms:
- cervical ca
- KS
- NHL
Bacterial:
- Recurrent pneumonias
- MTB
- MAC
- Other NTM
- Recurrent NTS
Viral
- CMV (except liver/RES)
- HIV encephalopathy
- HSV
- PML
Protozoal
- Cryptosporidioisis
- Isosporiasis
- Cerebral toxxoplasmosis
Fungal:
- PCP
- Oesophageal/bronchial cadidiasis
- Coccidomycosis
- Cryptococcosis
- Histoplasmosis
Describe the 95-95-95% targets
95% of PLHIV know their status, 95% of those who know their HIV status are on treatment, 95% of PLHIV on ART are virally suppressed
