Hello Dr. Mark,

1) Are t-cells gained during HAART as effective as ones lost pre-treatment? 2) Is a six month lab interval reasonable enough with a t-cell count >1000 and vl <50? 3) What VL is necessary to provoke a serious immune response (sans HAART)...1,000? 10,000? Baseline?

Thanks as always, You are the best!!

Great questions, hard to answer. #1. You would have to know the immune functional status of a person before infection, to answer this question directly. YOu would have to know how many cells they had and how effective their immune response was to various antigens, and then see if they were lost, and then regained after HAART. We do know that some response returns after treatment starts. Like against CMV and other kinds of infections. It unfortunately doesn;t come back against HIV specific antigens. #2. Yes to see increases or return against those antigens measured as described in #1. #3. I don't think those folks doing these studies have looked at the question in this kind of fine detail. And again is the question about other antigens or HIV specific antigens. The whole issue about treatment interrruptions is that having the viral load pop back up from being <50, allows the cytotoxic t cell response to reemerge. What level of viral load accomplishes this is currently unknown. MH