Background: Hematopoietic progenitor cells (HPCs) in the bone marrow of human immunodeficiency virus (HIV)-infected individuals have been proposed as a persistent reservoir of virus. However, some studies have suggested that HIV genomes detected in HPCs arise from T-cell contamination.
Methods: CD133-sorted HPCs and CD133-depleted bone marrow cells were purified from bone marrow specimens obtained from 11 antiretroviral-treated donors in whom the HIV load had been <48 copies/mL for at least 6 months. CD133 and CD3 expression on the cells was assessed by flow cytometry. HIV DNA was quantified by real-time polymerase chain reaction analysis.
Results: HIV genomes were detected in CD133-sorted samples from 6 donors, including 2 in whom viral loads were undetectable for >8 years. CD3(+) T cells represented <1% of cells in all CD133-sorted samples. For 5 of 6 CD133-sorted samples with detectable HIV DNA, the HIV genomes could not be explained by contaminating CD3(+) T cells. Donors with detectable HIV DNA in HPCs received their diagnosis significantly more recently than the remaining donors but had had undetectable viral loads for similar periods.
Conclusions: HIV genomes can be detected in CD133-sorted cells from a subset of donors with long-term viral suppression and, in most cases, cannot be explained by contamination with CD3(+) T cells.
Keywords: HIV; hematopoietic progenitor cells; reservoirs.