Fluctuations in HIV-1 viral load are correlated to CD4(+) T-lymphocyte count during the natural course of infection

Viral load fluctuates during the natural course of asymptomatic HIV-I infec tion. It is often assumed that these fluctuations are random around a set p oint or underlying growth trend. Using longitudinal data, we tested whether fluctuations in viral load can be better explained by changes in CD4(+) T- cell count than by a set point or trend of exponential growth. The correspo ndence between viral load and CD4(+) T-cell count could be described by a s imple mathematical relation. Using a bootstrapping approach, the hypothesis that viral load fluctuations are random around a set point was rejected wi th p < .00005. The hypothesis that viral load fluctuations are random aroun d a trend of exponential growth was rejected with p < .005. Viral load data was explained better by changes in CD4(+) T-cell counts than by a set poin t or by a trend of exponential growth. The implications of this finding for improved prognostication are discussed.