title: Human herpesvirus-6 and multiple sclerosis: relapsing-remitting versus secondary progressive.
abstract: Recently, it has been suggested that human herpesvirus-6 (HHV-6) may play a role in the pathogenesis of relapsing-remitting multiple sclerosis (RRMS), but there is not enough information related to the role of HHV-6 in secondary-progressive MS (SPMS). To address this question, we evaluated HHV-6 prevalence, active viral replication and viral load measured by quantitative real-time PCR, in DNA and mRNA extracted from peripheral blood mononuclear cells (PBMCs) and DNA extracted from serum; the samples were collected from 31 SPMS and 31 RRMS patients in a one-year follow-up study, and sex- and age-matched controls. The results were as follows: i) We found a statistical significant difference in HHV-6 DNA prevalences between RRMS and SPMS patients in: DNA extracted from PBMCs (P=0.027), DNA extracted from serum (P=0.010) and mRNA extracted from PBMCs (P=0.010). When we compared HHV-6 prevalences from RRMS patients in relapse and in remission with those from SPMS patients, we only achieved a statistical significance for the relapses (P=0.003 in DNA from PBMCs, and P<0.001 in DNA from serum samples and mRNA from PBMCs). ii) We only found HHV-6 variant A among HHV-6 positive samples in serum. iii) We did not find any difference in HHV-6 viral loads. These results suggest that HHV-6A does not play an active role in SPMS, while this virus may contribute to the pathogenesis of RRMS triggering MS attacks in a subset of patients.
authors.affiliation: Servicio de Neurología, Hospital Clínico San Carlos, Madrid 28040, Spain. labesmul@hcsc.es
authors.forename: Roverto
authors.initials: R
authors.lastname: Alvarez-Lafuente
authors.forename: Virginia
authors.initials: V
authors.lastname: de las Heras
authors.forename: Marta
authors.initials: M
authors.lastname: García-Montojo
authors.forename: Manuel
authors.initials: M
authors.lastname: Bartolomé
authors.forename: Rafael
authors.initials: R
authors.lastname: Arroyo
mesh_terms: D000328:Adult; D004279:DNA, Viral / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D015654:Herpesvirus 6, Human / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000453:epidemiology* / Q000821:virology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000453:epidemiology* / Q000821:virology*; D015995:Prevalence; D012333:RNA, Messenger; D019349:Roseolovirus Infections / Q000453:epidemiology*; D019562:Viral Load; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger