THY1 and cytomegalovirus infection: However, there are differences between subpopulations of progenitor cells: CD34+/CD38− cells support an HCMV infection with the hallmarks of latency, but a subset of CD34+/CD38− cells expressing a stem cell phenotype (lineage−/Thy-1+) support productive HCMV infection (Goodrum et al., 2004).