Characterization of gag gene of plasma HIV type 1 in combination therapy-treated AIDS patients with high viral load and stable CD4+ T cell counts.

Many AIDS patients retain a high CD4+ T cell count despite a significant increase in polymerase chain reaction (PCR)-determined viral load after various periods of treatment by combination therapy. Our study involved 10 such AIDS patients who showed this discordance. In this study, we characterized changes in the gag gene of HIV-1 isolated from the plasma of such patients. Viral RNA was extracted from plasma samples and the gag gene was amplified by reverse transcription-PCR. The PCR product was cloned and three clones from each patient were sequenced. All the sequences were aligned and compared with similar HIV-1 isolated from nontreated AIDS patients. Several kinds of changes were observed in the sequences including substitutions, frameshifts, and deletions. One patient showed a frameshift due to a missing G residue in the capsid-encoding region of the gene whereas another patient had virus with two different deletions. Such changes are probably due to combination therapy.