Role of viral load blips, drug boosting, and therapeutic holidays in HIV patient management.

IAS is a nonpro f i t organization founded in 1988, with more than 10,000 members representing more than 130 countries. This article addresses three main concepts discussed at the meeting that appear to play a role in the way clini-cians and laboratorians are currently approaching HIV patient management. Viral load blips are temporary spikes in viral load above 50 copies/mL that go back to undetectable levels on the next viral load test. Viral load blips are detected in 30–50% of patients whose viral load is otherwise stable and fully suppre s s e d. 1 , 2 Rises in viral load may be caused by variations in the tests themselves or anything that stimulates the patient's immune system such as a vaccination or infection. Additional causes for an increase in viral load are medication noncompli-ance or drug–drug interactions, which may lead to resistant virus. The frequency at which blips are detected depends on the frequency at which viral load testing is performed. I n t e re s t i n g l y, even though viral load blips are most frequent among patients with more drug experience, it seems that patients who blip are at no greater risk of virologic failure than patients who do not blip. 2 M o re than half of the patients who experience two consecutive viral blips between 50 and 400 copies/mL go to undetectable levels on the next test. When the blip exceeds 400 copies/mL the likelihood of returning back to below 50 copies on the next test is much lower, suggesting that the rebound may be a sign of true virologic failure. There is no evidence that HIV blips provoke a protective immune response to HIV but Interleukin-2 (IL-2) therapy is associated with controlled viral blips and an increase in the lymphoproliferative responses to HIV-1 specific antigens in patients receiving highly active antiretroviral therapy (HAART). 3 How to respond to these blips is still unclear because most patients who blip do return to undetectable viral levels but some do not. The role of the blips in predicting treatment failure is also unclear. The current recommendation for any rebound in viral load is to confirm the rise with a second test performed two weeks later and in the meantime to attempt to identify potential causes of the blip. Clinicians also recommend delaying viral load testing for at least two weeks after vaccination …