V. Muller et al., Release of virus from lymphoid tissue affects human immunodeficiency virustype 1 and hepatitis C virus kinetics in the blood, J VIROLOGY, 75(6), 2001, pp. 2597-2603
Kinetic parameters of human immunodeficiency virus type 1 (HIV-1) and hepat
itis C virus (HCV) infections have been estimated from plasma virus levels
following perturbation of the chronically infected (quasi-) steady state. W
e extend previous models by also considering the large pool of virus locali
zed in the lymphoid tissue (LT) compartment. The results indicate that the
fastest time scale of HIV-1 plasma load decay during therapy probably refle
cts the clearance rate of LT virus and not, as previously supposed, the cle
arance rate of virus in plasma. This resolves the discrepancy between the c
learance rate estimates during therapy and those based on plasma apheresis
experiments. In the extended models plasma apheresis measurements are indee
d expected to reflect the plasma decay rate. We can reconcile all current H
IV-1 estimates with this model when, on average, the clearance rate of viru
s in plasma is approximately 20 day(-1), that of LT virus is approximately
3 day(-1), and the death rate of virus-producing cells is approximately 0.5
day(-1). The fast clearance in the LT compartment increases current estima
tes for total daily virus production. Because HCV is produced in the liver,
we let virus be produced into the blood compartment of our model. The resu
lts suggest that extending current HCV models with an LT compartment is not
likely to affect current estimates for kinetic parameters and virus produc
tion. Estimates for treatment efficacy might be affected, however.