HIV i-Base: Training for Advocates, 10/2004www.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, 10/2004www.i-Base.info CD4 count - Marker for immune damage caused by HIV. Measured as ‘cells/mm3’ HIV-negative range Declines ~ 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, 10/2004www.i-Base.info 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 CD4 count.2

HIV i-Base: Training for Advocates, 10/2004www.i-Base.info 4-8 wksUp to 12 years 2-3 years Infection Seroconversion AsymptomaticSymptomatic AIDS Death CD4+ Cells/mm  mo CD4 history after HIV infection [without treatment] Time

HIV i-Base: Training for Advocates, 10/2004www.i-Base.info 4-8 wksUp to 12 years 2-3 years Infection Seroconversion AsymptomaticSymptomatic AIDS Death 2-12 mo CD4 history after HIV infection [without treatment] CD4+ Cells/mm3 200 Time Start treatment before CD4 goes below 200 cells/mm3

HIV i-Base: Training for Advocates, 10/2004www.i-Base.info 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 ‘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, 10/2004www.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, 10/2004www.i-Base.info 4-8 wksUp to 12 years 2-3 years Infection Seroconversion AsymptomaticSymptomatic 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, 10/2004www.i-Base.info 4-8 wks Up to 12 years 2-3 years Infection Seroconversion AsymptomaticSymptomatic AIDS Death CD4+ Cells/mm3 viral load mo 2 million 0 copies/mL Viral load after HIV-1 Infection [without treatment] Time

HIV i-Base: Training for Advocates, 10/2004www.i-Base.info 1-12 yrs+1-6 mo Chronic Infection Start treatment CD4+ cells/mm3 viral load (RNA) copies/mL million years !! < 50 copies/mL Viral load <50 copies/mL After HIV treatment (ARVs): effect on CD4 and viral load Time