HIV i-Base • STEP • EATG
HIV Training for Advocates
Section 1&2: CD4 and Viral Load Reduced slide set HIV i-Base: Training for Advocates, 10/2004
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CD4 count.1 •
CD4 count - Marker for immune damage caused by HIV. Measured as ‘cells/mm3’
•
HIV-negative range 600-1200.
•
Declines ~50-100 cells/year - AVERAGE
•
Closely matches the risk for becoming ill and used to provide prophylaxis treatment • >300 - very few HIV-related problems, except cancers (KS, NHL, lymphoma at any count). Reduced response to vaccinations. • 200–300 - water and food bourn problems (microsporidia, crytosporidia) + skin problems • <200 - PCP • <100 - MAI, MAC, toxoplasmosis • <50 - CMV + increased risk for everything else
HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
CD4 count.2 •
Used for deciding when to start HIV treatment - historical UK (2003) - when ≥ 200 cells/mm3 - (EuroSIDA) US (2003) - when ≥350 cells/mm3 (from 2003)
•
Used for deciding when to stop treatment
•
Used to monitor and treat with prophylaxis
One test result means nothing by itself - you need to follow results over time and the trend of any changes •
CD4% is the % of lymphocytes that are CD4 cells - the % can be more stable than count
•
Other factors: smoking, time of day, exercise, fatty meal
HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
CD4 history after HIV infection [without treatment] Death
Seroconversion Infection
Asymptomatic
Symptomatic AIDS
1000 CD4+ Cells/mm3
500 200 0 4-8 wks 2-12 mo
Up to 12 years
2-3 years
Time HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
CD4 history after HIV infection [without treatment] Death
Seroconversion Infection
Asymptomatic
Symptomatic AIDS
1000 CD4+ Cells/mm3
Start treatment before CD4 goes below 200 cells/mm3
500 200 0 4-8 wks 2-12 mo
Up to 12 years
HIV i-Base: Training for Advocates, 10/2004
Time
2-3 years www.i-Base.info
Viral load.1 (HIV RNA) 1. Measures level of virus (copies/mL) - usually in blood 2. New technology. Individualise care. Now widely used in other viral infections - (but scale of results is different) (ie with HCV is usually measure in millions)
3. Can influence when to start treatment (ie if â&#x20AC;&#x2DC;highâ&#x20AC;&#x2122; >100,000 copies/mL then predictive of progression), and in choice of treatment 4. 3-fold margin of error (ie 30,000 could be anywhere between 10,000 and 90,000 and still count as the same result) 5. This is the most important test when on-treatment HIV i-Base: Training for Advocates, 10/2004
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Viral load.2 (HIV RNA) When on-treatment: • viral load tests tell you if your treatment works • when your treatment fails • Whatever the starting level (baseline) - aim to get viral load to under 50 copies/mL (by3-6 months) • If still detectable resistance will develop and guidelines recommend changing treatment
HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
Viral load after HIV-1 Infection [without treatment] Death
Seroconversion Infection
Asymptomatic
Symptomatic AIDS
2 million viral load copies/mL
0 4-8 wks 2-12 mo
Up to 12 years
2-3 years
Time HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
Viral load after HIV-1 Infection [without treatment] Death
Seroconversion Infection
Asymptomatic
Symptomatic AIDS
2 million
1000 CD4+ Cells/mm3
viral load copies/mL
500 200
0
0 4-8 wks
2-12 mo
Up to 12 years
2-3 years
Time HIV i-Base: Training for Advocates, 10/2004
www.i-Base.info
After HIV treatment (ARVs): effect on CD4 and viral load Start treatment Viral load <50 copies/mL
2 million
1000 CD4+ cells/mm3
viral load (RNA) copies/mL
500 200
< 50 copies/mL
0
0 + 1-40+ years !!
1-12 yrs +1-6 mo Chronic Infection HIV i-Base: Training for Advocates, 10/2004
Time www.i-Base.info