Background: The natural course of the human immunodeficiency virus type 1 (HIV-1) infection is very variable. The factors which appear to determine the speed of immunodeficiency progression are multiple, although the virulence of the predominant viral strain seems to be one the main factors. The plasmatic viremia in individuals with rapid and slow HIV-1 progression was analyzed in an attempt to establish the degree of correlation between HIV-1 replication and the natural course of the disease.
Methods: Forty-two samples from 34 seropositive patients, 11 with rapid progression criteria (< 5 years from acute infection and CD4+ lymphocytes < 0.2 x 10(9)/l) and 23 with slow progression (> 7 years from demonstrated infection and > 0.5 x 10(9) CD4+ lymphocytes/l) were studied. The plasmatic viremia was quantified by a new method of plasma DNA genetic amplification, denominated the branched DNA (bDNA) technique. As a reference circulating p24 was determined and the presence of several proviral regions were studied in peripheral blood lymphocytes by polymerase chain reaction (PCR).
Results: The presence of RNA molecules was detected in plasma of 7 (58.3%) out of 12 samples of rapid progression (RP) patients by bDNA. To the contrary, this was negative in 30 samples from slow progression (SP) patients. Four of the 5 negative RP samples corresponded to patients who had taken antiretroviral drugs at the time of the study. The p24 antigenemia was positive in 5 (41.6%) from the RP patients and in none of the SP patients. The presence of gag, pol and env sequences was positive by PCR in all RP patients and in most of the SP patients. However, repeatedly negative results by PCR were observed in 5 SP samples for all or some of the genomic regions studied.
Conclusions: Patients with rapid progression of HIV-1 have higher plasmatic viremia than subjects with slow disease progression.