HUMAN CYTOMEGALOVIRUS-INFECTION OF THE MAJOR LEUKOCYTE SUBPOPULATIONS AND EVIDENCE FOR INITIAL VIRAL REPLICATION IN POLYMORPHONUCLEAR LEUKOCYTES FROM VIREMIC PATIENTS

Fourteen immunocompromised patients were examined for viremia, pp65 and p72 antigenemia, and presence of viral DNA in leukocyte fractions of polymorphonuclear leukocytes (PMNL), monocytes/macrophages (M/M), and B and T lymphocytes after purification by fluorescence-activated cell sorting. Nearly all PMNL and M/M fractions were positive for DNA and pp65 antigenemia, while p72 antigenemia was detected in 73% and 62%, respectively. The virus isolation rate was 45% from PMNL and 17% from M/M. T lymphocytes were positive for DNA in 50% of cases and for pp65 and p72 antigenemia in only 11%, while B lymphocytes were DNA-positive in 43% of samples and consistently negative for antigenemia; neither T nor B lymphocytes had virus isolated. Immediate-early (IE)1 RNA was present in 23 (85.2%) of 27 dextran-enriched DNA-positive p72-positive PMNL samples and, in sequential PMNL samples from two heart-transplanted patients, was detected during peak infection in association with p72. Thus, PMNL and M/M are the subpopulations primarily involved in HCMV infection; PMNL may undergo IE replicative events and are not merely passive carriers of phagocytized viral material.