Uninfected haematopoietic progenitor (CD34+) cells purified from the bone marrow of AIDS patients are committed to apoptotic cell death in culture

Objective: To determine the mechanism underlying the poor growth in vitro of haematopoietic progenitor cells isolated from HIV-1-infected patients. Method: Apoptotic death in liquid culture of bone-marrow CD34 + cells obtained from 11 HIV-1-seropositive patients and 18 HIV-1-seronegative donors was quantitatively monitored by a flow cytometry procedure. Results: No significant differences in the percentage of apoptotic cells were noted between the two groups immediately after purification. When CD34 + cells were placed in liquid cultures supplemented with 2 ng/ml interleukin-3, the number of apoptotic cells progressively and significantly (P <0.05) increased in all HIV-1-seropositive patients, while it remained constant in HIV-1-seronegative individuals. Although all HIV-1-seropositive patients showed signs of active viral replication in the bone-marrow micro-environment, progenitor CD34+ cells did not show the presence of active and/or latent HIV-1 infection. Results: Our data demonstrate that CD34+ cells isolated from AIDS patients with active HIV-1 replication in bone-marrow accessory cells are committed to apoptotic death without being directly affected by productive infection.