Prevalence of HHV-6A and HHV-6B was evenly divided in HIV+ patients in Western Africa, with over 6.3% positive for HHV-6 A and 5.0% for HHV-6B. HHV-6A was more common among those with a low viral HIV viral load.
Review of HHV-6 induced inflammatory cardiomyopathy in immunocompetent children
Although only a small number of pediatric cases have been reported in literature, the authors conclude that evidence suggests HHV-6 should be considered as a causative agent of inflammatory cardiomyopathy, particularly in young children (under 3 years of age) who might be experiencing a primary infection.
New study details devastating impact of HHV-6 encephalitis
Investigators in Japan studied 145 patients who developed HHV-6 encephalitis. At 100 days after transplantation, the overall survival rate was just 58.3%, compared with 80.5% for patients who did not develop encephalitis. High-dose antiviral therapy was shown to mitigate high mortality rates in these patients.
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.
Latent HHV-6A may impair myelin repair in multiple sclerosis
A group at University of Rochester demonstrated that the HHV-6A latency gene, U94, inhibits migration of cells involved in myelin repair. Inefficient myelin repair is associated with progression MS, and the ability of HHV-6A to impede this process suggests that it could be involved in the progression of MS, and raises questions about the virus’s role in other chronic demyelinating diseases.
HHV-6 reactivation associated with longer hospital stays, more readmissions in Memorial Sloan Kettering Trial
T-cell depleted stem cell transplant patients at Memorial Sloan Kettering Cancer Center with HHV-6 viremia, CMV viremia, or 2 or more viremias experienced longer hospital stays and were readmitted more often. HHV-6 was the most commonly reactivated virus, with 61% of patients affected patients .
Virus specific donor T cells found effective in treating HHV-6 and other viruses in Phase II clinical trial
“Off-the-shelf” donor T cells primed to fight five specific viruses were shown to be effective in a Phase 2 trial backed by Viracyte. A single infusion produced a complete or partial response rate of 92%.
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.
HHV-6 reactivation, monocytes and B cells are unusually elevated in cord blood transplant patients
CD8+ T cells recover but CD4+ T cells remain low
Investigators in France discovered that monocytes and B lymphocytes recover quickly and become abnormally elevated by day 75 in cord blood patients, while they remain below normal or normal in stem cell patients. Although CD8 T cells recover, CD4+ T cells remain below normal levels for six months in both groups.
Could HHV-6 U94 attenuate tumor cell growth and metastasis?
Italian investigators found that HHV-6 latency-associated gene U94, inserted in a HSV1 vector, inhibited the development of breast cancer, cervical cancer, and lung metastasis. It also impaired tumor driven angiogenesis.