CD34 and infection: Whether HCMV establishes a low-level productive infection in bone-marrow stromal cells (Taichman et al., 1997; Smirnov et al., 2007; Soland et al., 2014) or in a self-renewing CD34+ cell subset (Goodrum et al., 2004) also remains unclear, yet HCMV DNA has been detected in diverse tissue sites (Hendrix et al., 1997; Chen and Hudnall, 2006; Gordon et al., 2017) and recent RNA-seq uncovered HCMV transcripts at multiple locations, including the ovaries, blood, adipose tissue, and lung (Shnayder et al., 2018).