Viral Load or Virtual Virology?_full table

Table 1. Virologic and clinical summary for 66 consecutively studied HIV-1-infected patients.

"Circulating levels of plasma virus determined by QC-PCR also correlated with, but exceeded by an average of nearly 60,000-fold Table 1 [27], titers of infectious HIV-1 determined by quantitative endpoint dilution culture of identical portions of plasma. Several virologic and immunologic factors already identified in HIV-1 infection, including neutralizing antibody [28], viral envelope shedding [29], deterioration of other viral components [25], and genotypically defective virus [30] likely contribute to the differences in levels of circulating virus determined by QC-PCR and titers of culturable virus. However, the minimum requirements for establishment of productive infection of primary mononuclear cells are not known. If more than one intact viral particle is required to attain productive infection of a host cell, this would exaggerate the discrepancy observed between viral titers in plasma determined by QC-PCR as compared with those determined by endpoint dilution culture. For HIV-1 propagated in vitro, total virions have been reported to exceed culturable infectious units by factors of 10⁴ to 10⁷ [25], ratios similar to those we observed in plasma."

M. Piatak et al. "High levels of HIV-1 in plasma during all stages of infection determined by competitive PCR" (1993) Science 259: 1749-1754.