Human herpesvirus 6

Abstract

Human herpesvirus 6 (HHV‐6), a member of the β‐herpesvirinae subfamily, is highly seroprevalent, has a worldwide distribution, and infection usually occurs within the first two years of life. In this age group, HHV‐6 causes febrile illness including exanthem subitum with seizures a recognised complication. The virus is predominantly T lymphotropic although it can infect a variety of cell types in vitro and CD46 has recently been identified as a cellular receptor. The virus persists in the host, with a latent state proposed in monocytes and bone marrow progenitor cells, and chronic infection in salivary glands. The virus is pathogenic in the post transplantation period and may be a cofactor in the progression of HIV disease. The virus has also been associated with multiple sclerosis (MS), with the virus detected in oligodendrocytes particularly in plaque regions. The role of HHV‐6 in MS remains controversial and a more extensive understanding of its neurotropism and association with disease is required. Two variants of HHV‐6 exist (A and B) and comparison of their complete nucleotide sequences shows the genomes to be colinear, with a high degree of homology. Variation in specific regions of the genome is more extensive and probably accounts for biological and pathological differences. Almost exclusively, variant B is associated with febrile illness in childhood and is the predominant variant detected in healthy individuals. The epidemiology of HHV‐6A infection needs to be better defined, although it is significantly less prevalent. Biological, genetic, epidemiological and pathological findings suggest that the two variants are divergent. Copyright © 2000 John Wiley & Sons, Ltd.

Antibody status to HHV-6 in children with leukaemia

“…5,22,23 Both A and B subgroups of HHV-6 virus have a primary tropism for CD4 + T lymphocytes. There is evidence, that HHV-6 can directly target natural killer cells, thereby suppressing the natural anti-viral immunity of the host.…”

“…1 The peak of human herpesvirus-6 (HHV-6) infection is half a year earlier, and thus, could well contribute to the development of leukaemia. 2,3 HHV-6 was identified in 1988 as the cause of exanthema subitum, 4,5 which is characterised by a high fever during the presence of HHV-6 in CD4…”

“…9 The virus has been detected in tissue biopsies from lymphoproliferative disorders, such as S100-positive T cell chronic lymphoproliferative disease and Rosai-Dorfman disease. 5 A major issue concerning HHV-6 is the possibility of longterm infection. Salivary gland tissue is the site of virus replication and persistence.…”

Dermatological Skin Diseases Associated with Human Herpes Viruses 6, 7 and 8: Review

“…HHV-6 esas olarak T-hücre tropik bir virüs olmasına karşın, aralarında epitelyal hücreler, endotel hücreleri, fibroblastlar ve nöral hücrelerin bulunduğu pek çok hücreyi de enfekte edmektedir. 4 HHV-6 için selüler reseptör CD46'dır. 5 Virüsün latent olarak kalabilmesi ve replikasyonunun sınırlan-masında U94 geninin rol aldığı düşünülmektedir.…”

Epidemiologia molecular do herpesvírus humano tipo 6 (HHV-6) em crianças recém-nascidas e suas respectivas mães.

“…Os segmentos terminais e de junção das DRs contém repetição de telômeros de função indeterminada (GOMPELS et al, 1995), bem como contém 7 regiões de genes conservados entre todos os herpesvírus, um grupo de genes descoberto somente em ß-herpesvirus e alguns genes específicos para o gênero Roseolovirus (CLARK, 2000).…”