Natural history of serum HIV-1 RNA levels in 330 patients with a known date of infection. The SEROCO Study Group.

OBJECTIVE

To describe the spontaneous course, before the introduction of highly active antiretroviral therapy (HAART), of HIV-1 RNA during the AIDS-free period of the disease. To assess the predictive value of changes in HIV-1 RNA levels.

DESIGN

A total of 330 patients with a known date of infection followed in the SEROCO cohort.

METHODS

HIV-1 RNA levels (threshold, 200 copies/ml) were evaluated from 2243 frozen sera obtained from enrolment until the onset of AIDS or until February 1996. Lowess curves were used to describe the variations of viraemia during follow-up. A Cox regression model was used to assess the predictive value of early and updated CD4 cell count and viral load.

RESULTS

In addition to a lower early viral load, patients who remained AIDS-free had, on average, a longer period of viral load decrease after infection (36 versus 18 months), followed by a slower viral load increase compared with those who progressed to AIDS. A true plateau-phase after the seroconversion period, lasting approximately 4 years, was identified only in patients who remained AIDS-free for at least 90 months. In multivariate analysis, both early viral load and later changes were significant predictors of progression to AIDS. A decrease in the CD4 cell count to less than 200 cells/microl and the onset of a group B condition remained significant predictors of progression.

CONCLUSION

Our study extends to the early post-seroconversion phase the prognostic value of extracellular HIV-1 RNA levels. Moreover, our data suggest that, in most HIV-infected individuals, a progressive loss of control of viral replication arises during the early years of HIV-1 infection.