HIV replication in peripheral blood mononuclear cell (PBMC) cultures of HIV+ patients receiving highly active antiretroviral treatment (HAART) in the absence of mitogenic stimuli.

BARÉ P; BELMONTE L; PICCHIO G; PÉREZ BIANCO R; DE TEZANOS PINTO M; DE BRACCO MM; RUIBAL ARES B

Keystone, Denver Colorado, Estados Unidos

Simposio; Keystone Symposia on Molecular and Cellular Biology; 2000

Sustained negativization of plasma HIV RNA has been achieved in patients receiving HAART. Despite of this, infectious virus can still be recovered fron long term suppressed patients if peripheral blood resting memory CD4+ cells (CD45RO+/HLA-DR-) are selectively activated and cultured in vitro. It is also believed that cell types, other than CD45RO+/HLA-DR-/CD4+ T cells, may funtion as viral resrvoirs in vivo during succesful combined antiretroviral therapy. Here we demonstrate that monocytes/macrophages (M/M) can play such a role. Using a “prolonged” PBMC culture system in the absence of mitogenic stimuli described elsewhere (Ruibal Ares et al, Clin. Immunol. Immunopathol. 82 :106,1997), we studied 23 HIV+ hemophilic patients receiving HAART for 1-2 years. 10 cultures were stablished from 10 patients in whom plasma viral load (VL) levels had remained below 50 copies/ml for more than a year. HIV p24 Ag was detectable in the supernatant of 6 of these cultures to levels between 31-121 pg/ml. In addition, we studied 13 HIV+ hemophilic patients receiving HAART who responded well to therapy (increase in CD4+ cells, improvement in clinical status) but only achieved suppression of VL to levels between 50-400 copies/ml. HIV p24 Ag was detectable in the supernatant of all the cultures derived from these patients (n=13) levels between 30-120 pg/ml. Fluorescence microscopy analysis of cells present in positive cultures with a monoclonal antibody directed against p24 Ag (KC57) indicated that cells of the M/M lineage are mainly infected with HIV. These results obtained with our in vitro culture system confirm previous reports indicating that HIV eradication can not de achieved even after prolonged periods of plasma suppression. The localization of p24 Ag in cells of the lineage and the low level of detection of this Ag in culture supernatants suggests that this cell type is the main source of HIV in our culture system lacking mitogenic stimuli. In addition to memory resting CD4+ cells, cells of the M/M lineage can function as viral reservoirs during HAART.