CD4% Clarifying what it means?

[wiser]

Can anyone reinforce or explain a bit the significance of the CD4% as opposed to the T Cell count in terms of assessing how well the immune system is functioning?

I've been taking Sustiva/Truvada(Atripla) for about 3 years. Been HIV+ since May 2004. My VL has been <50 since starting treatment and T Cell count went from a low of 89 to 234. The T cells have pretty much plateaued at 230 for over a year now, which had me a little discouraged. My last labs showed a drop in T Cells to 174 (Jan 2008). I am demoralized with that news as I keep wanting to see T cells move to the 300s at least. But they don't budge and now have for the first time taken a down turn. My doctor told me today to focus on the CD4% which has gone from 11% to 39% since starting treatment and has continued to rise. I reread the Lesson on this site on T cells and CD4% as I had not gone reviewed this since 3 years ago. But I am confused/ T Cells below 200 put one at high risk for pneumonia and other OIs. So that is bad news. BUT CD4% AT 39% is quite good and suggests the immune system has had some reconstituiton and should work moderately well. That is good news. Does the CD4% trump the low T Cell count in terms of my assessing how strong my immune system is? I had blood work done today so I will see if the drop in T-cells was a one time blip rather than a trend. My doctor is putting the focus on the CD4% for now. It just feels like he is trying to make me feel good and not panic at the sudden drop in T Cells from 230 to 174 ... which feels ominous to me.

[Matty the Damned]

Well, your doctor is on the right track here.

The absolute CD4 count is prone to wild fluctuations. Things which can affect your CD4 absolute level include the time of day, whether you slept well the night before, if you've given the booze a bit of a nudge and so on.

The CD4 percentage is considered to be a more reliable indicator of immune function because it's less prone to such fluctuations and can gives a clearer picture of how your immune system is travelling. Indeed a percentage of 39 is very good as it is within the normal range and suggests that you're probably not gonna be wiped out by an OI.

In any event, I'd trust my doctors advice if I were you. You're doing well.

MtD

[newt]

Both CD4 count and CD4% are good indicators of immune system's health.

CD4 count varies by time of day, whether you slept, had a cold etc - and from test to test because CD4 counts are only accurate to +/- 50. CD4% varies less on an hour to hour basis, but it still varies.  You need to look at the trend for both.

Regardless of CD4%, CD4 count -- if it's accurate -- is predictive of the risk of opportunistic infections, 200 being the critical cut-off.

Your rise in CD4% probably represents a great improvement in your immune function. Whether you have reached a plateau remains to be seen. A result like yours -- lower CD4 count for the CD4% than expected -- needs to be read with a full white blood count. CD4% is your CD4 count as a % of all white blood cells. If you have less white blood cells for some reason, the % will be higher. A CD4 test only indicates the number of CD4 cells in your blood. Most of your CD4 cells are is somewhere else, eg lymph nodes. Hence my comment on the count being accurate.

- matt

[wiser]

Thanks to both of you. You gave me the clarification and reinforcement I needed.