Detection of Cytomegalovirus DNA in CD34' Cells From Blood and Bone Marrow

Infection of hematopoietic progenitor cells with the human cytomegalovirus (HCMV) has been proposed as an explanation for the cytopenias associated with HCMV-related disease. To test this hypothesis, CD34+ cells, which include the hematopoietic progenitors, as well as mature leukocyte populations were purified on a fluorescence-activated cell sorter and analyzed for HCMV DNA by polymerase chain reaction (PCR). A total of 33 samples from 31 immunosuppressed as well as immunocompetent HCMV-seropositive individuals were studied. CD34+ cells were PCR-positive in four of seven bone marrow aspirates from allogeneic bone marrow transplant recipients, in three of eight aspirates from patients with acquired immunodeficiency syndrome, and in the first of two bone marrow samples from an immunocompetent patient with primary HCMV disease. CD34' NFECTION WITH the human cytomegalovirus (HCMV) is frequently associated with leukopenia and thrombocytopenia in the immunocompromised host and newborn infant.l-3 Several possible mechanisms of HCMV-induced myelosuppression have been postulated. In vitro, a decreased production of hematopoietic growth factors from HCMVinfected bone marrow stroma has been de~cribed.~.' In addition, CD8+ lymphocytes exposed to HCMV can suppress hematopoiesis in vitro.6 Furthermore, susceptibility of hematopoietic precursors for HCMV in vitro could be demonstrated using a recombinant HCMV containing the Escherichia coli lacZ gene.' Some investigators found that infected progenitors had a reduced proliferative potential in vitro, but others could not confirm this finding.4" In contrast with the extensive data from in vitro studies, very little is known about the tropism of HCMV for hematopoietic progenitor cells in vivo. We have recently shown that during viremia, immediate early (IE) and late viral mRNA is expressed in all mature leukocyte populations and that granulocytes represent a major site of late mRNA expression." Granulocytes circulate in the blood for only a few hours, which is much shorter than the time span between