Quantification of a very low level of serum human immunodeficiency virus type 1 (HIV-1) RNA using competitive PCR at...

Quantification of human immunodeficiency virus type 1 (HIV-1) genomic RNA levels below the detection limit (400 copies/ml) of commercially available quantification kits is possible by increasing the amount of serum samples using competitive PCR conditions. We evaluated disease prognosis in patients without symptoms for a long period after infection (long-term non-progressors) and patients in whom the virus was controlled to a low level by administration of anti-HIV drugs. For 102 of the 414 serum samples stored at -80 degrees C which showed HIV-1 RNA below 400 copies/ml by competitive PCR using 100 to 200 microl sera, an increase in the sample volume to 500-2000 microl, extraction of HIV-1 RNA, and quantitative detection by competitive PCR was performed. Follow-up quantification of serum HIV-1 RNA from 4 patients indicated that this method is useful in assessing prognosis in the early stage of the disease in patients without symptoms for a long period after infection (long-term non-progressors) and patients in whom the virus in the serum was controlled by administration of anti-HIV drugs to below the detection limit of commercially available quantification kits. Quantification of low level serum HIV-1 RNA was also considered useful as a parameter of treatment.