Human herpesvirus 6 (HHV6) DNA persistence and reactivation in healthy children.
OBJECTIVE
To determine in healthy children after primary infection the persistence of human herpesvirus 6 (HHV6) DNA, the presence and frequency of HHV6 re-activation or re-infection, and the relationship of both to illness and the presence of human herpesvirus 7 (HHV7) infection.


METHODS
Children 1 to 12 years of age with previous HHV6 infection were prospectively evaluated by HHV6 and HHV7 DNA polymerase chain reaction (PCR) and reverse transcription (RT)-PCR for HHV6. HHV6 plasma antibody titers were measured. Illnesses were recorded by diary, and physician records were reviewed.


RESULTS
HHV6 DNA was detected in >or=1 peripheral blood mononuclear cell (PBMC) samples in 89% of children. HHV6 reactivation and re-infection were detected by RT-PCR in 1.1% of samples. Detection of HHV6 DNA was intermittent in 76% of children and was not associated with cumulative rates of illness. Illness at a study visit was significantly associated with the absence of HHV6 and HHV7 DNA in PBMC samples and was not associated with HHV6 antibody titer or the presence of HHV6 DNA in saliva.


CONCLUSIONS
HHV6 DNA persists in most children intermittently following primary infection and is unrelated to illness. Reactivation of HHV6 occurs in healthy children without apparent illness.
Department of Pediatrics, University of Rochester School of Medicine, Rochester, New York, USA. mary_caserta@urmc.rochester.edu <mary_caserta@urmc.rochester.edu>
Mary T
MT
Caserta
Michael P
MP
McDermott
Stephen
S
Dewhurst
Kenneth
K
Schnabel
Jennifer A
JA
Carnahan
Lynne
L
Gilbert
Gladys
G
Lathan
Geraldine K
GK
Lofthus
Caroline B
CB
Hall
D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D015654:Herpesvirus 6, Human / Q000302:isolation & purification / Q000502:physiology*; D016199:Herpesvirus 7, Human / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007963:Leukocytes, Mononuclear / Q000821:virology; D008297:Male; D011446:Prospective Studies; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019349:Roseolovirus Infections / Q000821:virology*; D014775:Virus Activation