1 Immune system and CD4 count

1.13 Use of CD4 count for starting therapy

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The main use of CD4 counts is to know when to start HIV treatment

If HIV drugs were perfect – with no side effects and no resistance – then everyone would use treatment as soon as they were diagnosed.

However, they are not perfect.

This means you need to decide when the risk of not using treatment is greater than the generally low risk of using treatment. When the benefits of treatment are greater than the risks of treatment, it makes sense to use treatment.

At what CD4 count should someone start ARV treatment?

• WHO and UK guidelines recommend people who have no symptoms start ARVs before their CD4 count falls below 200.
• US treatment guidelines recommend people who have no symptoms start ARVs before their CD4 count falls below 350.
• All guidelines recommend people who have HIV related symptoms or illnesses start ARVs even if their CD4 count is over 350.

Several large studies have also shown that people who start treatment with a CD4 count of 200 compared to people starting at 350 or above, get a similar benefit from treatment.

In general, people are unlikely to have HIV-related illnesses when their CD4 count is over 200 cells/mm³.

Several years ago both UK and US treatment guidelines recommended starting at higher levels. They may change again in the future – especially if better and easier to tolerate drugs become available, and trials show this to be a good idea.

Remember that any one count is just a general figure. It doesn't matter very much whether you start treatment at 180 or 220 – but generally around 200 is better than waiting until it drops much lower.

In practice, many people who start treatment at much lower levels will still do very well.

Many people are only diagnosed with HIV when they have HIV-related illness and CD4 counts that are under 200.

The highest risk of complications, treatment failure and side effects are in people with the lowest CD4 counts.