Inherited ciHHV-6 has been shown to activate under conditions of immunosuppression and and the pan-HDAC inhibitor TSA activates integrated ciHHV-6 in vitro. This is the first case report of HHV-6 activation in a ciHHV-6 patient who received a pan-HDAC inhibitor drug.
Ancient iciHHV-6 genomes vary considerably from community strains, but still capable of reactivation
British researchers used molecular dating methods to determine that most strains of iciHHV-6 come from a small number of ancient human ancestors; the youngest found lived over 24,000 years ago. These ancient strains vary considerably from modern non-inherited strains of HHV-6A and appear just as likely to activate as their more modern cousins.
Multiple herpesvirus infections lead to telomere shortening
Investigators at Kings College London report that seropositivity for CMV, Herpes simplex 1 and HHV-6 are all associated with a significant shortening of telomeres over a three-year period. Furthermore, the magnitude of the changes was large. For example, CMV seropositivity was associated with the equivalent of almost 12 years of chronological age.
Blood virome sequencing reveals new data on roseolovirus prevalence and epidemiology
Sequencing of over 8,000 individuals were used to determined the prevalence of 94 different viruses. HHV-7 was the most common virus, with HHV-6B and HHV-6A 4th and 5th respectively.
In Japan, inherited ciHHV-6A likely derived from common ancestor
A team in Japan has reports that ciHHV-6A prevalence is influenced by a “founder effect” and is likely derived from a common ancestor. All of the individuals in the small study were found to have HHV-6A integrated into the telomeric region of chromosome 22, a common site of integration.
Inherited ciHHV-6 increases risk of developing acute GVHD and CMV in transplant patients
A higher prevalence of inherited virus was found in patients
Investigators at Fred Hutchinson Cancer Center determined that transplant patients with inherited ciHHV-6 were twice as likely to develop acute graft vs host disease and three times more likely to develop high level CMV viremia. Transplant patients were also significantly more likely to have inherited ciHHV-6 than donors.
A more efficient form of latency? HHV-6A persistence depends on telomeric repeats, not circular episomes
Most herpesviruses maintain latency by forming circular episomes in the nucleus of the cell. Investigators in Germany have provided further evidence that HHV-6A relies on their telomeres, not circular episomes, to maintain a persistent latent infection by integrating into the host chromosome.
New cell culture system established to study HHV-6A/B chromosomal integration
A group led by Louis Flamand, PhD in Canada has developed a culture system that can be used to determine how the virus enters latency by integrating into the chromosome, and which drugs cause it to activate.
Solo DR and non-telomeric chromosomal integration
A new study shows that HHV-6A direct repeats can survive alone in an integrated state without the rest of the viral genome. The study also identified non-telomeric integration of HHV-6A in both in vitro cultured cells as well as one iciHHV-6A patient.
Neoplasia: could iciHHV-6A cause a benign HPV strain to turn deadly?
Human papillomavirus 4 is a benign strain not associated with cancer. However, in a woman with inherited chromosomally integrated HHV-6A, a high grade vaginal squamous lesion developed rapidly. The authors warn that there may be a synergistic effect between HPV4 and iciHHV6A.
Opinion: call for ciHHV6 screening in transplantion
Two physicians from Texas propose that ciHHV6 status of donors and recipients be determined before solid organ transplantion, using a single pre-transplant qPCR test on whole blood, and that patients with ciHHV-6 or ciHHV-6 donors be carefully monitored for signs of active HHV-6 infection.
Does the high level of U94 in iciHHV-6 contribute to abnormal ‘marker’ chromosomes and cancer?
Investigators from the University of Ferrara, Italy have found evidence suggesting that high levels of U94 in ciHHV6 may predispose to the formation of marker chromosomes. A patient with diffuse large B-cell lymphoma positive for inherited chromosomally integrated HHV-6A and HHV-6A was also found in a marker chromosome, an abnormal piece of chromosome that is seen in some leukemia and lymphomas.
Possible inherited chromosomally integrated HHV-7 identified in two patients
Investigators led by Bhupesh Prusty, PhD at University of Wurzbürg in Germany have identified two cases of possible germline inherited chromosomally integrated HHV-7.
ciHHV-6B activation and fetal transmission in response to high dose progesterone?
A pregnant ciHHV-6B woman with a history of miscarriages was given weekly doses of high dose progesterone. Could progesterone, like hydrocortisone, activate integrated ciHHV-6 in vitro.
Surprise finding : HHV-6 telomeric repeats are crucial for HHV-6 integration
When the research team led by Benedikt Kaufer attempted to shed light on the mechanism behind HHV-6 integration, they were suprised to find telomeric repeats were critical to the integration process. Since the U94 gene shares homology and biological properties with the adenovirus Rep68 gene responsible for viral integration into human chromosomes, U94 was considered the most likely candidate to mediate HHV-6 integration.