Human herpesviruses 6 and 7: effects on hematopoiesis and mode of transmission.
Human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) were recently discovered, and are known as etiologic agents of exanthem subitum (roseola). HHV-6 and HHV-7 are T-lymphotropic, and have been classified as betaherpesviruses. In monitoring of herpesviruses after hematopoietic stem cell transplantation, each herpesvirus had a unique temporal profile of detection. HHV-6 DNA was detected most frequently at 3 weeks, whereas cytomegalovirus and Epstein-Barr virus DNA were detected later. HHV-7 DNA was not detected throughout the observation period. In in vitro hematopoietic colony assays, HHV-6 suppressed all three lineages of hematopoiesis, i.e., erythroid, granulocyte/macrophage, and megakaryocyte, whereas HHV-7 did not have any suppressive effect. Molecular epidemiological analysis revealed that HHV-7 was transmitted horizontally from grandparents to parents to children through close contact within a household. Either parent could transmit HHV-7 to the children. Follow-up studies of the amount of viral DNA in saliva samples revealed that the amount of HHV-7 DNA was rather constant for each individual, and that "high producers" and "low producers" could be distinguished. Transferred antibodies against HHV-7 tended to be higher and remain longer after birth than those of HHV-6, and these findings are consistent with the clinical observation that HHV-6 infection occurs earlier than HHV-7 infection.
Yamada
M
M
Department of Virology, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan. masao@md.okayama-u.ac.jp
D000914:Antibodies, Viral / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000009:adverse effects; D003114:Colony-Forming Units Assay; D004279:DNA, Viral / Q000032:analysis; D018562:Disease Transmission, Infectious; D006084:Graft Rejection / Q000209:etiology; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects; D006412:Hematopoietic Stem Cells / Q000821:virology; D006566:Herpesviridae Infections / Q000276:immunology / Q000635:transmission* / Q000821:virology; D015654:Herpesvirus 6, Human / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D016199:Herpesvirus 7, Human / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D006801:Humans; D007962:Leukocytes / Q000821:virology*; D008533:Megakaryocytes / Q000821:virology; D016133:Polymerase Chain Reaction; D012463:Saliva / Q000821:virology; D013997:Time Factors; D019562:Viral Load
D000914:Antibodies, Viral; D004279:DNA, Viral