DISTINCT CHANGES IN HIV TYPE-1 RNA VERSUS P24 ANTIGEN LEVELS IN SERUM DURING SHORT-TERM ZIDOVUDINE THERAPY IN ASYMPTOMATIC INDIVIDUALS WITH AND WITHOUT PROGRESSION TO AIDS

Serum HIV-1 RNA and p24 antigen levels were examined in 28 seropositive asymptomatic individuals participating in a trial on the efficacy of zidovudine, Sixteen individuals remained asymptomatic until 4 years after the onset of the trial, whereas 12 individuals were diagnosed with an AIDS-defining event, The serum HIV-1 RNA load and p24 antigen levels were determined before the onset of therapy and during the first 8 weeks of therapy to establish whether the patterns of change were predictive of clinical outcome, Among the 28 participants 43% had measurable pretreatment concentrations of p24 antigen, Initiation of zidovudine therapy was followed by a similar decline of p24 antigen levels in nonprogressors as well as progressors and, therefore, these groups could not be distinguished on the basis of this parameter, HIV-1 RNA was detected in the pretreatment samples of 82% of the individuals and could be detected in p24 antigen-positive as well as p24 antigen-negative individuals, Similar changes in HIV-1 RNA load during zidovudine therapy were observed in p24 antigen-positive and -negative individuals, Analysis of the HIV-1 RNA response according to clinical outcome demonstrated that HIV-1 RNA copy numbers had declined significantly after 4 weeks of therapy in both nonprogressors and progressors, but the decline in RNA load was much stronger in the nonprogressors, Our data show that the HIV-1 RNA load in serum can be used to monitor the response to antiviral therapy in p24 antigen-positive as well as -negative individuals. Posttreatment changes in p24 antigen levels are not indicative for clinical outcome, whereas RNA copy numbers are, Therefore, monitoring p24 antigen levels is less valuable than HIV-1 RNA following antiretroviral therapy.