HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

Section 1&2: CD4 and Viral Load

Reduced slide set

HIV i-Base • STEP • EATG

HIV Training for Advocates

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

• 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

CD4 count.1

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

• Used for deciding when to start HIV treatment - historicalUK (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 prophylaxisOne 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

CD4 count.2

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

4-8 wks Up to 12 years 2-3 years

Infection

Seroconversion

Asymptomatic Symptomatic AIDS

Death

1000

500

0

CD4+ Cells/mm

200

2-12 mo

CD4 history after HIV infection[without treatment]

Time

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

4-8 wks Up to 12 years 2-3 years

Infection

Seroconversion

Asymptomatic Symptomatic AIDS

Death

2-12 mo

CD4 history after HIV infection[without treatment]

1000

500

0

CD4+ Cells/mm3

200

Time

Start treatment beforeCD4 goes below 200 cells/mm3

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

1. Measures level of virus (copies/mL) - usually in blood2. 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 ‘high’ >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

Viral load.1 (HIV RNA)

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

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

Viral load.2 (HIV RNA)

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

4-8 wks Up to 12 years 2-3 years

Infection

Seroconversion

Asymptomatic Symptomatic AIDS

Death

2-12 mo

Viral load after HIV-1 Infection[without treatment]

viral load

2 million

0

copies/mL

Time

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

4-8 wks Up to 12 years 2-3 years

Infection

Seroconversion

Asymptomatic Symptomatic AIDS

Death

1000

500

0

CD4+ Cells/mm3

viral load

200

2-12 mo

2 million

0

copies/mL

Viral load after HIV-1 Infection[without treatment]

Time

HIV i-Base: Training for Advocates, 10/2004 www.i-Base.info

1-12 yrs +1-6 moChronicInfection

Start treatment

1000

500

0

CD4+ cells/mm3

viral load (RNA)copies/mL

200

2 million

0

+ 1-40+ years !!

< 50 copies/mL

Viral load <50 copies/mL

After HIV treatment (ARVs): effect on CD4 and viral load

Time