Discordant responses during antiretroviral therapy: role of immune activation and T cell redistribution rather than true CD4 T cell loss.

We studied T cell dynamics in four patients who initially responded well to highly active antiretroviral therapy (HAART) but subsequently experienced virological failure. Maintenance of peripheral blood CD4T cell counts was associated with low levels of immune activation. Low reactivity to rebounding virus may preserve normal T lymphocyte distribution over blood and tissues and be associated with stable peripheral blood T cell numbers in virological failures to HAART.