Other than viral load, what do you think is the best marker for progression? Isn't high anti p-24 antibody count considered a very good immune correlate of protection, better even than CD4 count or CD4/CD8 percentage? Why isn't this marker tested for more often, esp. in clinical trials? I understand the present antirretrovirals don't impact much on anti-p24 ab count. Would a hypothetical antiretroviral that lowered VL as well as current drugs but also raised the anti-p24 antibody levels be considered a superior treatment? Thank you for your interesting and valuable service!

You're welcome!

I haven't heard of people using the p24 antibody as a marker for progession, but it was quite common at one time to use p24 antigen. Perhaps that's what you're referring to. If not, my apologies.

I was never very convinced that the p24 antigen was terribly useful, even back when people were using it. In large cohort trials, it was somewhat predictive of progression, but it was hard to figure out how to use it clinically in individual patients. Now that viral load assays are available, I really can't think of any reason to measure p24 antigen in individuals, or in clinical trials, for that matter.