Biphasic decline of CD4 cell count during scheduled treatment interruptions

In 115 patients whose scheduled treatment interruptions (STI) lasted 24 weeks, the CD4 cell count declined by a median of 30 cells/ml/week during the first 4 weeks, compared with 3 cells/ml/week during the next 20 weeks. In multivariate regression, a pronounced early fall in CD4 cells correlated with a higher CD4 cell count at the start of STI, with more gain in CD4 cells during antiretroviral treatment preceding STI, and with a higher viral load at week 4.