CD4% Drop After Med Start

Question

I started meds at the beginning of January. I started with a CD4 of 454 at 21%. All the years I was not on meds, my percentage was never below 21%. I got my first labs since starting meds and CD4 went up to 526, but my CD4% dropped to 16%. My CD8 was 1,300 in October, but jumped to 2,030 this time.

I still don't fully understand how the percentage is calculated. But, I am confused why it would drop like that. One would think it should stay the same or be climbing. Not on meds, I know 16% would stick out like a sore thumb, being so close to the 14% that is considered AIDS defining. I'm not sure if my immune system is actually worse, or whether the percentage doesn't matter now.

Answer

You don't indicate what your HIV viral load response has been. A few other numbers that might be helpful in looking at this would be the total white blood cell (WBC) count, total lymphocyte count, and CD8%. In general, we would not usually see such an increase in CD8 count/percent after starting HIV treatment. I suspect what is driving the CD4% down is an increase in CD8 count/percent, as the fraction of total lymphocytes that are t-lymphocytes has increased significantly as CD8 cells, driving the CD4 percent down. I would predict this will stabilize once your HIV viral load becomes undetectable for a period of time.