Quantitative competitive PGR is a highly sensitive technique that allo
ws accurate quantitation of small amounts of RNA. We have modified the
original method to include the use of an internal standard at all sta
tes of sample analysis. In this way, the method can accommodate for va
riations in the recovery of viral particles and in the isolation of ge
nomic RNA as well as provide a suitable competitive substrate during q
uantitative RNA PCR. We have used this method to characterize changes
in virus load in plasma of HIV-1-seropositive individuals following th
eir vaccination against opportunistic infections. (C) 1997 Academic Pr
ess.