Human herpesvirus 6 and multiple sclerosis: a one-year follow-up study.
BACKGROUND
This study was undertaken in order to investigate the possible relation of HHV-6 and EBV in relapsing-remitting MS (RRMS).


METHODS
A one-year follow up study was performed analysing peripheral blood mononuclear cells and serum samples of 57 patients with RRMS and 57 healthy blood donors (HBD) by a quantitative real time PCR, to detect HHV-6 and EBV. Clinical data (starting age and EDSS increase) were collected.


RESULTS
We did not find any statistically significant difference for EBV between RRMS patients and HBD. Regarding HHV-6: i) There was a higher prevalence of HHV-6 in RRMS patients than in controls: 80.7% versus 29.8% respectively. ii) HHV-6 active replication seems to be related to exacerbations. iii) Only variant A was detected among RRMS patients with HHV-6 active replication. iv) Although some difference was found when we compared clinical data in RRMS patients with and without HHV-6 active replication, the results did not reach statistical significance.


CONCLUSIONS
A higher HHV-6A frequency of active infection (reactivation or new infection) would lead to a more frequent exposure of HHV-6A antigens to the immune system of RRMS patients; this active replication of HHV-6A seems to be specifically related with the exacerbations in a subset of RRMS patients.
Alvarez-Lafuente
Roberto
R
Servicio de Neurología, Hospital Clínico San Carlos, Madrid, Spain. labesmul@hcsc.es
De Las Heras
Virginia
V
Bartolomé
Manuel
M
García-Montojo
Marta
M
Arroyo
Rafael
R
D000293:Adolescent; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D004854:Herpesvirus 4, Human / Q000235:genetics; D015654:Herpesvirus 6, Human / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000821:virology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000503:physiopathology / Q000821:virology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012367:RNA, Viral / Q000096:biosynthesis / Q000235:genetics; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019562:Viral Load
D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral