Viral rebound follow up

Question

This is a follow up to the question on July 16th.

In your answer you clearly state that there is little data on viral rebound after ceasing antivirals. However you imply that rebound would be faily rapid.

I have been under the impression that if a person is undetectable for a year or two, most of the hiv producing cells have died off. If this is the case, wouldn't it take a fair amount of time for the hiv to reinfect enough cells to produce a baseline viral load?

Thank you for your reply.

Answer

Of what little data there is regarding rebound, most is from people who had detectable viral loads. It was documented because of nonadherence, or in those people who voluntarily stopped because of toxicity, resistance etc. If viral load was detectable (implying ongoing replication), pretreatment levels could be seen in as little as one week off therapy. Recent data has shown that despite "undetectable viral load" in blood (< 50 copies/ml), and no active expression in lymph nodes, virus could be cultured from lymph node cells implying the presence of a reservoir of cells that can produce virus. A few people who stopped their regimen in this situation were shown to have detectable viral load in 2-4 weeks. There is little data looking at daily time points after stopping to look at the slope of ascent. Other data has also shown that in people who are on effective therapy(ie AZT/3TC/Indinavir), undetectable viral loads and who stop the protease inhibitor, viral load will rebound.

MH