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.
New evidence linking HHV-6A U24 protein to MS
HHV-6 has been linked in numerous studies to multiple sclerosis. Now, investigators at the University of British Columbia have published new data suggesting that HHV-6A may be a key player in the development of multiple sclerosis. The investigators propose that the viral protein U24 may dysregulate myelination.
HHV-6 identified in 12% of simple and 42% of complex pediatric febrile seizures
Australian investigators studied 143 young children with febrile seizures for signs of viral infection and found that HHV-6 was the fifth most common virus after rhinovirus (22%), enterovirus (20%), adenovirus (21%) and influenza (13%). Overall, a virus was found in 71% of cases. Virus found in complex seizures was associated with HHV-6 (42%) or influenza (41%).
Rapid point-of-care system screens for 14 encephalitis pathogens in one hour!
A new point-of-care assay from bioMérieux can simultaneously and rapidly detect 14 pathogens typically found in encephalitis. The machine is designed to be at the clinic or in the emergency room and can be operated by unskilled technicians. In a study of 1,560 immunocompetent patient samples, a total of 1.35% were positive for HHV-6, or about twice the expected rate of 0.8% found with the inherited chromosomally integrated HHV-6.
HHV-6 found to cause 35% of CNS infections in allo-HSCT transplantation
A retrospective analysis out of the Tokyo Metropolitan Cancer and Infectious Diseases Center reviewed 353 consecutive adult allogeneic hematopoietic stem cell transplant (allo-HSCT) cases and identified 17 cases of CNS infection post-transplant. As determined by PCR on cerebrospinal fluid, HHV-6 was found to be the causative agent in 6 cases, or 1.7% of all transplants.
HHV-7 homolog found in the peripheral nerve ganglia of macaques
Virologists led by Serge Barcy, PhD at the Seattle Children’s Research Institute and University of Washington have identified a homolog for HHV-7 in pigtail macaques They were surprised to learn that it could be detected in the peripheral nerve ganglia, and hope to use their new animal model to explore how HHV-7 might play a role in demyelinating diseases.
HHV-6A gene activity linked to central nervous system disease
Chinese investigators from Nanjing Medical University report that HHV-6A infection of astrocytes are associated with differences in gene expression that are also found in several CNS diseases including Alzheimer’s, glioma and multiple sclerosis. The investigators used gene ontology analysis to determine the biological processes, cellular components, and molecular functions of the differentially expressed genes and signalling pathways.
EBV and HHV-6B but no CMV found in astrocytomas by digital droplet PCR
A group from the National Institute of Neurological Disorders and Stroke, NIH, has reported finding Epstein-Barr Virus (EBV) and HHV-6 but no cytomegalovirus (CMV) in astrocytomas, a brain tumor comprising approximately one quarter of all gliomas diagnosed. The group used digital droplet PCR (ddPCR), a technique that is highly precise but less sensitive than nested PCR and immunohistochemistry, techniques that have been used in previous studies.
GAD antibodies & HHV-6 limbic encephalitis – a case of molecular mimicry?
A fifth case of limbic encephalitis associated with GAD antibodies and HHV-6 infection has been reported, this time in an immunocompetent woman with chromosomally integrated HHV-6, epilepsy, and psychosis. The patient’s condition improved (with a drop in GAD antibody titers and stabilization of psychotic symptoms) in response to three weeks of antiviral therapy but relapsed when antiviral therapy was withdrawn.
HHV-6 & 7 found in spinal fluid of immunocompetent children suspected of CNS infection
An Italian study on immunocompetent children with suspected CNS infections found HHV-6 and HHV-7 DNA in 4.2% and 4.8% of 304 cerebrospinal fluid (CSF) samples, respectively. Although once considered rare in the immunocompetent, recent studies with more sensitive methods have found HHV-6 in the CSF of 4-17% of immunocompetent children with seizures or suspected CNS infections.
Saliva DNA load for HHV-6 (but not HHV-7) elevated in caregivers of patients with dementia
Investigators associated with a dementia center at Kobe University Hospital found that saliva HHV-6 DNA levels may serve as an objective marker for caregiver exhaustion. The saliva HHV-6 DNA levels in caregivers (log 3.04 copies/ ml) were significantly higher than in those of non-caregivers (2.78 copies/ml).
Can depression, psychiatric disorders and fatigue be triggered by a neurovirulent latent HHV-6B protein?
Three virologists led by Kazuhiro Kondo, MD, PhD, a professor of virology at Jikei University School of Medicine, have filed a patent on a method to diagnose and treat prevent mood disorders which he says are initiated by latent and neurovirulent HHV-6B residing in glial cells, and that this condition can be treated effectively with nasal sprays, using the olfactory nerve as a route to the brain. Dr. Kondo has named this protein SITH-1 or “small protein encoded by intermediate state transcript”.
HHV-6 induced Parkinsonism post-transplant
A group of researchers from Sao Paulo, Brazil reported the development of HHV-6 infection in the striatum of a 32-year-old man six weeks after allogeneic hematopoietic stem cell transplantation. This is the first reported case of HHV-6 infection affecting the striatum and presenting with Parkinsonism post-HSCT.
HHV-6 the only pathogen identified in early post-transplant CNS dysfunction
A group from Sapporo Medical University studied 105 post HSCT patients and determined that 7 developed CNS dysfunction in the first 42 days after transplant. Six out of the 7 were positive for HHV-6, but none of the other 12 pathogens tested. Four patients (3.8%) were diagnosed with HHV-6 encephalitis. The group used a qualitative multiplex PCR and then used a quantitative PCR to confirm the results.