A group led by Mara Cirone in Italy found that HHV-6B blocks autophagy in HSB-2 cells. Both HSV-1 and CMV have proteins that block autophagy, and HHV-6B carries genes that are homologues of those encoding for CMV’s anti-autophagy protein. Her next step is to study the impact of both HHV-6A and HHV-6B on autophagy in neuronal cells.
RNA sequencing of HHV-6B transcriptome identifies U38 as the best target for HHV-6 RT-PCR testing
Investigators at University of Washington studied multiple samples to develop an assay that can detect active infection in patients with chromosomally integrated HHV-6. Current quantitative PCR DNA testing cannot determine whether a ciHHV6 patient has active replication.
NEJM HIGHLIGHTS A CASE OF HHV-6 REACTIVATION IN DRESS
The NEJM rarely covers HHV-6, but did an excellent case history of this patient with HHV-6 reactivation in conjunction with DRESS. The patient was not treated with an antiviral in spite of a plasma HHV-6 DNA load of 112,836, extensive lymphadenopathy, rash and abnormal liver function tests. What did NEJM get wrong? They stated ciHHV6 could be ruled out because …
Infection with HHV-6A/B speeds progression of disease in marmoset model of MS
Marmosets infected with HHV-6A/B intranasally were initially asymptomatic but later developed significantly accelerated disease and died in a shorter period of time. HHV-6 proteins were found at high levels in the brain lesions.
Genomic analysis finds a surprising association between ciHHV-6 and two genes
A genomic analysis of samples from 141,431 Chinese women found a highly significant association between ciHHV-6 and a variant in the MLCI-MOV10L region. The MLC1 gene is involved in myeloid cell differentiation and the MOV10L1 gene may allow for more efficient integration during spermatogenesis.
Rapid lymphocyte expansion after HCT predicts increased HHV-6 reactivation
A team of researchers at Kyoto University in Japan reported that rapid lymphocyte expansion is a good predictive factor for increased HHV-6 reactivation, as well as reduced CMV antigenemia. Patients with aplastic anemia as a primary disease had a 5 fold increased risk of HHV-6 reactivation.
Mycophenolate mofetil tied to increased risk of HHV-6 encephalitis after allogenic transplantation
Japanese investigators found that those who were administered mycophenolate mofetil along with a calcineurin inhibitor developed a much higher rate of infection: 12% in cord blood and 6% in other transplants.
New standardized approach to the evaluation of antivirals for DNA viruses
A new method to assess antiviral activity against DNA viruses has been developed, using automated format and qPCR to measure the accumulation of viral DNA. Of the FDA approved drugs, foscarnet showed the highest selectivity index for HHV-6B.
HHV-6 and EBV found in the brain tissue of Rasmussen’s Encephalitis patients
Chinese investigators found a high prevalence of HHV-6 and Epstein Barr virus in the brain tissues of children with Rasmussen’s encephalitis but in none of the controls. There was a significant association between viral presence and brain atrophy, raising a strong suspicion for the involvement of both viruses.
Novel antiviral compound with unusual mechanism of action found to work well for HHV-6A and CMV
In a study led by Manfred Marschall German investigators analyzed the potency of novel pyrrolopyridine-class compounds and found one that is highly active against CMV and HHV-6A. It works at an early stage of viral protein production, and differs from ganciclovir in mechanism.
MAPK upregulation by HHV-6B proposed as the mechanism behind link to epilepsy.
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.
Could this be why HHV-6 is better than other herpesviruses at establishing latent infection?
German investigators suggest that silencing of HHV-6A by the ND10 complex may explain why HHV-6A is more likely than other herpesviruses to establish a quiescent infection.
Why did these transplant protocols result in such a high rate of HHV-6 encephalitis (32%) and organ disease (46%)?
Investigators in Spain and Italy attempted to reduce the rate of acute GVHD in pediatric transplant patients by infusing manipulated stem cells. Not only was there no reduction in expected acute GVHD, the patients experienced an unusually high rate of HHV-6 disease.