In contrast, latent infection has so far been characterized in cells of the early myeloid lineage, including CD34+ hematopoietic stem and progenitor cells (HSPCs) and CD14+ monocytes in vivo (Mendelson et al., 1996; Taylor-Wiedeman et al., 1991; von Laer et al., 1995). This evidence concerns the gene CD14 and disease arising from reactivation of latent virus.