title: Lymphoproliferative responses to human herpesvirus-6 variant A and variant B in healthy adults.
abstract: Human herpesvirus-6 (HHV-6) isolates can be classified into variants A and B, and over 95% of people older than 2 years of age are seropositive for either or both variants. However, the prevalence of the two HHV-6 variants is still not defined since the serological methods used at present cannot discriminate one variant from the other. Lymphoproliferative responses to glycine extracted cellular antigens from human herpes-virus-6 (HHV-6) GS strain (variant A)- and Z 29 strain (variant B)-infected T-lymphoid cell lines were examined in healthy Swedish and Japanese adults. Nine of 36 (25%) persons had responses to the GS antigen, while 21/36 (58%) had responses to the Z 29 antigen (P=0.008). Individuals with low anti-HHV-6 IgG titers (< or = 320) were more likely to respond to the Z 29 antigen than to the GS antigen (P=0.006), while there was no difference in those with high anti-HHV-6 IgG titers (> or =1280). Three of 7 Japanese adults had lymphoproliferative responses to the GS antigen compared with 6/29 Swedes (not significant), and 7/7 Japanese had lymphoproliferative responses to the Z 29 antigen compared with 14/29 Swedes (P=0.03). Lymphoproliferative responses were neither related with the presence of HHV-6 DNA nor related with the presence of HHV-7 DNA in peripheral blood cells. These results suggest a higher prevalence of HHV-6 variant B than variant A in both Swedes and Japanese adults, and possibly a difference in either the HHV-6 virus strains and/or the nature of immune response of Swede and Japanese.
authors.affiliation: Department of Virology, Swedish Institute for Infectious Disease Control, Stockholm.
authors.forename: F Z
authors.initials: FZ
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Dahl
authors.forename: P
authors.initials: P
authors.lastname: Ljungman
authors.forename: A
authors.initials: A
authors.lastname: Linde
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000276:immunology / Q000302:isolation & purification; D003587:Cytomegalovirus / Q000276:immunology; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006566:Herpesviridae Infections / Q000097:blood / Q000453:epidemiology / Q000276:immunology; D014645:Herpesvirus 3, Human / Q000276:immunology; D015654:Herpesvirus 6, Human / Q000737:chemistry / Q000276:immunology*; D016199:Herpesvirus 7, Human / Q000302:isolation & purification; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007564:Japan; D007962:Leukocytes / Q000276:immunology / Q000821:virology; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D019590:Nucleocapsid Proteins / Q000276:immunology / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012698:Serologic Tests; D013548:Sweden
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D004279:DNA, Viral; D007074:Immunoglobulin G; D019590:Nucleocapsid Proteins