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.
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.
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.
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.
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of psychotic symptoms) in response to three weeks of antiviral therapy but relapsed when antiviral therapy was withdrawn.
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.
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).
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”.
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.
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