The Puzzle of CD4-Cell Depletion Despite Good Viral Suppression

We expect that when combination antiretroviral therapy (ART) suppresses a patient’s HIV viremia, a steady increase in CD4-cell count will ensue. In some patients, however, such increases are minimal or fail to occur, and in others, CD4-cell counts plummet after an initial rise, even though viral load remains undetectable. The combination of ddI and tenofovir has been associated with these aberrant CD4-cell responses, but the underlying mechanism is unclear, and the phenomenon is also seen in patients taking other drugs.

In a recent study, NIH researchers sought evidence to support any of several hypothetical explanations for the aberrant CD4-cell responses seen in four patients on combination ART whose CD4 counts had fallen from a median of …