Phase II Study of Autologous Myeloid Dendritic Cells as a "Cellular Adjuvant" for a Therapeutic HIV-1 Vaccine in Early Stage HIV-1+ Patients (DCV-2).

Our group has reported recently the first human trial of 4 therapeutic immunizations at six-week intervals with autologous monocyte-derived dendritic cells (MD-DC) loaded with heat-inactivated autologous HIV in 12 HIV infected patients who had been receiving highly active antiretroviral therapy (HAART) since early chronic infection. Autologous HIV was concentrated from plasma (1,500 ml) obtained by plasmapheresis after a 3-month HAART interruption (STOP1) performed 78 weeks before therapeutic immunizations, and HAART was discontinued again (STOP2) after therapeutic immunization. There was a decrease of set-point plasma viral load (PVL) >= 0.5 log after 24 weeks off HAART in 4 out of 12 patients. In addition, we observed a significant lengthening in mean doubling time of PVL rebound (p= 0.01), and significant decreases in the area under the curve of PVL rebound (p= 0.02) and in the mean peak PVL (p= 0.004) during the 12 weeks after STOP 2 compared with STOP1. This virological response was associated with a weak but significant increase in HIV-1 specific CD4 lymphoproliferative response, and with changes in HIV-1 specific CD8+ T-cell responses in peripheral blood and in lymphoid CTL cells after immunization. In lymphoid tissue, we also observed a trend towards a better control of HIV-1 replication coupled with an increase of CD4+ and CTL cells. No significant virological or immunological changes occurred in controls. We show that a therapeutic vaccine with autologous MD-DC pulsed with heat inactivated autologous HIV-1 is feasible, safe and well tolerated and elicited weak and transient cellular immune responses against HIV, associated with a partial and transient control of HIV replication in some patients.

we hypothesized that a DC vaccine pulsed with higher amount of autologous virus obtained by culture could be more effective than the vaccine we used.