Swedish investigators set out to uncover the pathways that HHV-6B might utilize in triggering MTLE. They found that HHV-6B infection altered expression of MAPK genes, suggesting a possible pathogenic mechanisms of HHV-6B in mesial temporal lobe epilepsy.
Acute seizures in children: a new study highlights the role of infections and inflammation
NINDS investigators found that children with febrile seizures have elevated inflammatory cytokines compared to healthy controls and children with fever. One of those cytokines, Il-1β, correlated with HHV-6 saliva viral load.
Active HHV-6A/B found in the cerebellar Purkinje cells in patients with mood disorders
HHV-6 was found more frequently in the Purkinje cells of bipolar and major depressive disorder patients compared to controls. Furthermore HHV-6A was associated with a reduced Purkinje cell size. HHV-6 was not found, however in patients with schizophrenia.
Gene-expression network analysis points to HHV-6A as a key driver in upregulating genes leading to Alzheimer’s disease progression
Investigators at Mt Sinai used “big data” models to determine that the genes involved with fighting Alzheimer’s are the same ones that fight virus. They found HHV-6A and HHV-7 to be more abundant in Alzheimer’s brains, and singled out HHV6-A as a key modulator of the genes involved in amyloidosis and neuronal death.
HHV-6 and HSV1 dramatically accelerate amyloid plaque production in Alzheimer’s model
Researchers at Harvard studied how neurons responded to the presence of herpesviruses HSV1 and HHV-6, and found that they rapidly induce amyloid plaque production within 24 to 48 hours.
Infants with HHV-6B seizures are 15X more likely to develop febrile status epilepticus
A large prospective study in Africa adds weight to argument that HHV-6B infection is an important cause of febrile status epilepticus.
HHV-6 encephalitis in 32% of pediatric leukemia patients depleted of naïve T cells
Although depleting naïve T cells has been successful in preventing acute graft vs host disease in several studies, investigators from Spain reported an unexpectedly high incidence of HHV-6 encephalitis in a cohort of haploidentical transplant patients.
Dense infection of the hippocampus in primary HHV-6B encephalitis
The autopsy of an infant with HHV-6B encephalitis showed a 4-5 fold increase in the viral load of the hippocampus compared to other parts of the brain. Neurons, oligodendrocytes and vascular endothelial cells were infected, but not astrocytes or microglia.
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.
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.
Low sodium levels associated with HHV-6 encephalitis
Retrospective analysis of transplant patients revealed that low serum sodium levels are associated with HHV-6 encephalitis, but not HHV-6 myelitis. Low sodium is a possible marker for HHV-6 encephalitis post-transplantation.
Antibodies to herpesvirus dUTPase a potential biomarker for Gulf War Illness and CFS
Antibodies to HHV-6 and VZV dUTPases were significantly elevated in Gulf War Illness patients compared to controls, and EBV dUTPase antibodies were elevated in Chronic Fatigue Syndrome patients.
HHV-6B induces telomeric hypomethylation, possibly facilitating integration
HHV-6B induces unique, region-specific DNA hypomethylation, and findings suggest that the epigenetic modification may facilitate HHV-6B integration.
Decreased HHV-6 IgG in Alzheimer’s
Investigators from Uppsala University in Sweden found that HHV-6 IgG reactivity was significantly lower in Alzheimer’s Disease patients compared to controls. The authors suggest reduced immunity may be one reason why past studies have found increased levels of HHV-6 DNA in the brains of Alzheimer’s patients compared to controls.
HHV-6 induced amnesia after rituximab therapy for autoimmune disease
A young woman on rituximab and two other immunomodulatory agents for the treatment of dermatomyositis developed encephalitis with severe anterograde amnesia. As the use of biologic treatments for refractory autoimmune disease has been increasing, physicians are advised to consider HHV-6 and offer prompt antiviral therapy to limit irreversible morbidity.