Elevated plasma levels of acute phase markers in AHI prior to detection of viremia Samples collected at sequential time points spanning the eclipse and viral ramp-up phases from 19 US plasma donors who acquired HIV-1 infection were studied to gain insight into the kinetics of the earliest systemic anti-viral defenses activated in the acute phase of infection. Plasma was typically obtained from each donor at intervals of 2-5 d. Plasma panels were tested for HIV-1 by RT-PCR analysis of viral RNA titers, and time courses from different donors were aligned relative to the time point (T 0 ) when viremia first reached levels detectable by conventional assays (.100 RNA copies ml 21 ; Fig. 1A ). Most panels covered a timeframe from around d 220 to d +20 relative to T 0. It is currently thought that the eclipse phase in HIV-1 infection is in the range of 7-10 d [12, 15] hence most panels likely included samples collected from time points prior to the acquisition of infection onwards.