A number of astronauts have complained about herpesvirus reactivations during flight, and several developed shingles. Investigators at NASA determined that space flight increases herpesvirus shedding in saliva, compared to levels before and after their missions.
Does corticosteroid use for aGVHD prophylaxis lower HHV-6 reactivation by reducing IL-6?
A new study reports a surprisingly low rate of HHV-6 reactivation in recipients of half-matched bone marrow grafts using a reduced-intensity conditioning regimen. The authors speculate that the corticosteroid used for prophylaxis may have suppressed cytokine production which in turn limited reactivation of HHV-6.
Foscarnet approved for HHV-6 encephalitis in Japan
Although foscarnet is widely used for HHV-6 encephalitis, it has never been specifically approved for HHV-6. Japan’s Ministry of Health, Labor and Welfare was the first to approve foscarnet (Foscavir) for the treatment of HHV-6 encephalitis.
HHV-6 increases risk of an “idiopathic” pneumonia syndrome after HCT as does murine roseolovirus in a BMT mouse model. Early HHV-6 was also found to increase non-relapse mortality
Investigators from University of Michigan have demonstrated that murine roseolovirus is a useful homolog for the study of HHV-6 reactivation in lung disease. In a large retrospective study of HCT patients, they also found early HHV-6 reactivation to increase the risk of both idiopathic pneumonia syndrome and non-relapse mortality.
Herpesviruses may reduce NK cell cytotoxicity in Alzheimer’s
MS patients with a particular haplotype on natural killer cells are more susceptible to HHV-6A infection. Similarly, HHV-6A/B may contribute to Alzheimer’s by utilizing a specific NK cell inhibitory receptor to disrupt the ability of NK cells to clear infected cells.
89% of the virus found in the spinal fluid of HCT patients in the first 60 days is HHV-6
An analysis of 165 central nervous system viral infections by the Center for International Blood and Bone Marrow Transplant Research found that most were positive for HHV-6. The outcome for patients with viral infection was poor with 50% mortality within 6 months and only 30% survival at 5 years.
HHV-6 is a greater risk than CMV for rejection in pediatric kidney transplantation
Investigators from the Children’s Hospital of Mexico found that although CMV caused the biggest increase in risk for liver rejection, HHV-6 was the more important infection associated with rejection of kidney transplants. A single HHV-6 infection resulted in an increased risk of over 5 fold, while a coinfection of EBV, HHV-6 and HHV-7 increased the risk of kidney rejection by over 17 fold.
HHV-6 is the most common virus found in trigeminal and facial nerves
Herpesviruses are common in the trigeminal and facial ganglia, latently infecting 64% of cases. HHV-6 was the most commonly identified herpesvirus in these tissues — about half of all autopsy specimens were found to have the virus in trigeminal and/or facial ganglia.
HHV-6 but not HHV-7 correlates with nerve fiber damage in fibromyalgia patients
HHV-6 was found to be significantly correlated with nerve fiber damage severity by Latvian investigators. 51% of fibromyalgia patients had detectable HHV-6 DNA in whole blood compared to just 6% of controls.
HHV-6 in Cancer: Does it play a role?
Since its discovery, HHV-6 has been studied in the context of lymphoproliferative disorders and various types of cancer. Several obstacles, particularly the ubiquitous nature of the virus, have made it difficult to determine exactly how HHV-6 might, or might not, be involved in tumor development.
Stanford finds high levels of HHV-6 in the tissues of children with liver failure
A team at Stanford reported that 48% of young children with “liver failure of unknown etiology” had high viral loads of HHV-6 in their liver tissues. As a result, Stanford has now instituted routine evaluation for HHV-6 in all children who present with liver failure.
HHV-6A receptor CD46 identified as a critical factor in ‘awakening’ endogenous retrovirus
Both infectious and UV-inactivated HHV-6A activate endogenous retrovirus envelope protein – but so does selective stimulation of HHV-6A’s CD46 receptor. This “cross-talk” between HHV-6A and endogenous retrovirus appears to play an important role in the pathogenesis of inflammatory diseases.
Porcine cytomegalovirus to be re-classified as a roseolovirus
Porcine CMV is an immunosuppressive virus that inhibits T-lymphocyte and macrophage immune functions, and like HHV-6A, it causes infertility. Porcine CMV infection also reduces the survival of pig xenotransplants.
New findings on how HHV-6A/B U94 blocks angiogenesis
The HHV-6 latency gene U94 has been found to block angiogenesis, but the mechanisms behind this phenomenon have been unclear. A team lead by Roberta Rizzo and Elisabetta Caselli in Italy shed light on this process, opening the door to new potential molecular targets to pursue in treating diseases marked by improper vascularization.