Dynamics of viral load in plasma and HIV DNA in lymphocytes during highly active antiretroviral therapy (HAART): high viral burden in macrophages after 1 year of treatment.

In this study we evaluated the level of HIV RNA in plasma and HIV DNA in peripheral blood cells. Sixteen antiretroviral-experienced HIV patients with severe immune suppression were included in the study. After the first month, 56.2% of the patients showed undetectable levels of HIV RNA, this percentage remaining stable after 1 year (53.3%). At enrollment, 7 patients (43.7%) with a low CD4+ T cell count (mean 22 per mm3 versus 73) showed HIV DNA levels below the limit of detection (5 copies/10(5)) in lymphocytes. They all subsequently had increased HIV DNA that became detectable between the first and the third month of therapy, associated with an increase of the CD4+ T cell count (mean 22 to 95/mm3); in 4 of these patients this increase was transitory, becoming undetectable again after one year. In 7 out of the 8 patients with detectable HIV DNA at enrollment, the HIV DNA level decreased over time. Seven out of 15 patients at 1 year (46.7%) showed both undetectable levels of HIV RNA in plasma and HIV DNA in lymphocytes (p<0.05); these patients had a higher CD4+ T cell count at baseline (mean 75 versus 25/mm3) and a higher increase (306 versus 177/mm3) after 1 year. PCR-based dilution assay carried out at 1 year showed that all patients had a consistent amount of HIV DNA positive- CD4+ T lymphocytes and macrophages, with higher values in these last cells. The data indicate that a durable reservoir of virus is still present in both lymphocytes and monocytes, even after long-lasting HAART treatment.