Stability of human immunodeficiency virus RNA in blood specimens as measured by a commercial PCR-based assay.

We investigated the effects of conditions often encountered during handling, transit, and storage of blood specimens on the quantity of detectable human immunodeficiency virus (HIV) RNA in plasma. HIV RNA copy numbers were measured with a commercially available assay (the Amplicor HIV-1 Monitor test kit). Variables examined were the time to processing of blood and plasma, the holding temperature of blood and plasma prior to processing, the effect of freezing and thawing of plasma, and the use of different anticoagulants. The relationship between the HIV RNA copy number and the HIV isolation rate by peripheral blood mononuclear cell (PBMC) coculture was also examined. We found that RNA copy numbers were maintained to within 0.5 log10 (approximately threefold) in blood and plasma samples held at room temperature or 4 degrees C for up to 3 days and remained stable despite (limited) freezing and thawing of the plasma. HIV RNA copy numbers were also maintained after long-term storage of plasma at -70 degrees C. The ability to isolate HIV from PBMCs was directly proportional to the HIV RNA copy number.

Long-term foscarnet therapy not associated with the development of foscarnet-resistant human immunodeficiency virus type 1 in an acquired immunodeficiency syndrome patient.

Sequential human-immunodeficiency virus type 1 (HIV-1) isolates from an acquired immunodeficiency syndrome (AIDS) patient on long-term foscarnet and zidovudine therapy were examined for the emergence of foscarnet resistance. One isolate obtained before therapy, and three post-foscarnet therapy HIV isolates had similar foscarnet sensitivity profiles, despite the emergence of foscarnet-resistant herpes simplex virus type 2 (HSV-2) during the period of therapy. Virion reverse transcriptases from these isolates were also equally inhibited by foscarnet. In contrast, sequential HIV isolates taken pre- and postzidovudine therapy showed a gradual increase in IC50 to this drug. In this patient, long-term foscarnet and zidovudine therapy selected foscarnet-resistant HSV and zidovudine-resistant HIV; in contrast, HIV remained susceptible to foscarnet. Concurrent administration of other anti-HIV drugs (zidovudine and interferon-alpha) may have hindered the development of foscarnet resistant HIV-1 in vivo.