Question
Where can I find studies on reasons for CD4 count changes?
23 April 2012. Related: All topics, CD4 and viral load.
In lots of questions here you talk about the variation in CD4 count and that they change during the day and can be affected by diet and excercise. What are the studies that show this so I can read a bit more about this.
Thanks for great site BTW.
Answer
Thank you for your question.
A number of studies have looked at this question and confirm that CD4 counts are not accurate fixed results. They fluctuate throughout the day for example lower readings in the morning and higher later in the day etc. If you were to have a test every week, they would probably change even more. For example, your CD4 count is generally 50 cells higher in the morning compared to at night, and can be affected in a similar superficial way by diet and excercise and other infections.
Below, please find a couple of studies looking at this question.
- The first one is a key study by J Malone and others. This study has also been quoted in a number of other studies. It looked at the reasons for and extent of CD4 count variations.
- The second study by GH Mientjes and others, looked at changes in CD4 cell count and T-function among drug users.
It should be remembered that only approx 2% of HIV is circulating in the blood stream, with the rest being located in the lymphatic tissues and other resting sites.
CD4 cell results are a simple surrogate marker which over time provides the trend that tends to determine treatment decisions.
Fluctuations of 50 cells between tests are not significant, and it is sometimes better to refer to the CD4% result as this tends to be less volatile.