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New mouse model of HHV-6A infection shows persistent abortive infection and neuroinflammation via TLR9

An article published in the Journal of Virology this month details novel findings from a newly developed transgenic mouse model of HHV-6A infection.  Dr. Branka Horvat’s team at the International Center for Infectiology Research in Lyon, France, developed the model by using transgenic mice expressing human CD46, identified as a receptor for HHV-6A.  The study suggests that the presence of HHV-6A in the CNS, even if only a latent or abortive infection, can have a strong impact on inflammation through TLR-9 induced upregulation of CCL5, CCL2, CXCL10 and CDCL1.  READ MORE

HHV-6 may play a significant role in patients with Bell’s Palsy

Although a leading cause of Bell's Palsy is thought to be reactivation of latent herpes simplex virus (HSV) or varicella-zoster virus (VZV), a group from Sapienza University of Rome has found that HHV-6 was not only significantly more prevalent in saliva, the viral load was also higher in patients with Bell’s Palsy compared to controls. Furthermore, patients with the worst cases had a significantly higher viral load. These findings led the group to conclude that HHV-6 may be involved in the development of the disease, or that the underlying disease mechanism might predispose patients to HHV-6 reactivation.  READ MORE

HHV-6 saliva DNA levels in chemotherapy patients lowered by mushroom extract known to boost cellular immune response

A study conducted by the Osaka University Graduate School of Medicine sought to evaluate the safety and effectiveness of a mushroom product, active hexose correlated compound (AHCC), on chemotherapy-induced adverse effects and quality of life (QOL) in patients with cancer.  Quality of life worsened and the DNA levels of HHV-6 were significantly increased after chemotherapy course in the untreated patients. However, the group treated with AHCC had significantly improved QOL and decreased the levels of HHV-6 DNA in saliva after chemotherapy. The mean viral load was 1083 copies/ ml in the untreated group compared to 254 copies/ml in the treated group (P<0.05). The drop in HHV-6 saliva viral load also correlated with decreased hematotoxicity and hepatotoxicity. These findings suggest to the authors that salivary HHV-6 DNA levels may be a good biomarker of QOL in patients during the course of chemotherapy. READ MORE

Digital Droplet PCR Assay for HHV-6 shows promise for detecting low-grade infection and identifying ciHHV6.

Two papers published this month highlight the potential of the new 3rd generation PCR assays for samples with very low viral loads (MS patient sera) and for identifying ciHHV6 in PBMCs. In a paper published this month in PLOS One, Steve Jacobson’s group at NINDS/NIH used techniques to increase the sensitivity of the ddPCR assay, allowing an exploration of low copy number viruses such as HHV-6 in MS serum. Although levels of HHV-6A and HHV-6B DNA typically fall below the level of detection in all but acutely ill patients (or those with ciHHV6), Jacobson’s group found HHV-6 DNA in 30% of the serum and 57% of the PBMCs of healthy controls, with control HHV-6B levels found to be consistently higher than HHV-6A levels.  The study also found that MS patients had significantly more HHV-6A detectable in saliva than healthy controls (30% vs 12%) as well as a higher viral load.  

Keith Jerome’s group at the University of Washington has also begun utilizing ddPCR technology in the field of HHV-6 diagnostics.  In a study published this month, their team has reported the validation of an assay designed to confirm ciHHV6 status using cellular samples. The group compared HHV-6 DNA levels to the number of cells and found that ciHHV6 patients produced a genome-to-cell ratio very close to 1:1. READ MORE

HHV-6B protein DR6 identified as inducer of cell cycle arrest in G2/M

While it is known that HHV-6B infection inhibits cellular proliferation at the G2/M phase, no protein had previously been identified as a causative agent to enact this inhibition.  In a new article published in Virology this month, Dr. Hollsberg’s team at Aarhus University in Denmark has identified the protein responsible for this crucial mechanism of cell-cycle specific interruption.  Through a series of findings, the group has identified the protein product of direct repeat 6, DR6, as an inhibitor of G2/M cell-cycle progression.  READ MORE