[Rapid and slow progression of the infection by the type 1 human immunodeficiency virus in a population of seropositive subjects in Madrid].

BACKGROUND

The rate of progression to AIDS in HIV-1 infected subjects is variable, and circumstances associated with more rapid or slow development of severe immunodeficiency might be grouped in three categories; environmental cofactors, host features, and particular virulence of the virus itself. Currently, it is not yet clear the the relative impact of each one.

PATIENTS AND METHODS

A cross-sectional study was done in a cohort of 1,783 IV-1 infected persons from three centers located in Madrid, mainly devoted to attend persons at risks for HIV infection. Long-term nonprogressors (LTNP) were defined as those with more than 8 years of confirmed HIV seropositivity, and CD4+ T-cell count above 500 x 10(6)/I in the absence of antiretroviral therapy or symptoms suggesting immunodeficiency. Rapid progressors (RP) were those with less than 5 years from seroconversion and repeatedly current CD4+ T-cell count below 200 x 10(6)/I. An analysis of different epidemiological, immunological and virological features was performed comparing LTNP and RP.

RESULTS

Among 1,783 HIV (+) subjects studied, 100 (5.6%) fulfilled criteria for LTNP and 12 (0.7%) for RP. Among LTNP, stabilized CD4 slope was seen in 16 (33%) out of 48 after more than 8 years of infection. Variables statistically associated with LTNP were: past history of intravenous drug addiction (80% of them), male gender (79% of them), high alcohol intake (48% of them), HIV-1 non-syncitium inducing viral phenotype, and very low or undetectable HIV-1 plasma viremia. In contrast, variables associated with RP were: infection by sexual contact (75% of cases), female gender (50% of them), syncitium-inducing viral plenotype, and high titers of plasma viremia. The CD4/CD8 ratio below 1 was seen in all RP and in 88% of LTNP. However, a preferent depletion of CD4+ cell occurred in the first group, instead of an enhancement of the CD8 T-cell count in LTNP. The prevalence of serological markers for hepatotropic viruses and other potential infectious cofactors was not higher in RP.

CONCLUSIONS

Multiple factors seems to account for the different rate of disease progression observed in HIV-1 infected persons. The dynamic equilibrium between the immune system and the virulence of the virus seem to be influenced--but not determined--by environmental infectious or non infectious cofactors.