HHV-6/7 DNA was found in the plasma of 19.6% of epilepsy patients compared to none of the controls. Protein expression, indicating active infection, was found in 53% of the HHV-6/7 positive patients.
Researchers at the NIH used RNA-Seq cells from skin and blood to study the underlying mechanisms in DIHS/DRESS and identified both HHV-6 and JAK-STAT pathways as potential targets. Central memory CD4+T cells were enriched with HHV-6B.
Two groups have challenged the widely-publicized 2018 study in 2018, that found increased HHV-6A & 7 abundance and an association with clinical and pathology scores in Alzheimer’s. The topic has become the focus vigorous debate.
Building on their prior work, an Italian team has shown that HHV-6A is able to induce dysregulation of autophagy in neurons and astrocytoma cells, increasing amyloid beta and tau production.
Karolinska Institute researchers developed a novel serological assay to determine that individuals with antibodies to HHV-6A early proteins are more likely to develop MS. HHV-6A antibodies were the highest in the presence of elevated EBV antibodies, suggesting that the two viruses could jointly contribute to the development of MS.
Investigators propose that the induction of endoplasmic reticulum stress, likely exacerbated by autophagy inhibition, could contribute to the immune suppression induced by HHV-6B in exanthem subitem patients.
A review of post-transplant cases found that the incidence of HHV-6 myelitis was 4.1%; symptoms of pruritus without rash, pain, numbness, dysuria and constipation are potential signs.
Japanese investigators evaluated cytokines and chemokines in the CSF and plasma in HHV-6 encephalitis patients with good and poor prognoses. They found IL-6, IL-7, MCP-1 to be elevated one week before onset, suggesting that these cytokines may be effective targets for intervention.
MIT examined transcription across tens of thousands of individual cells in both Alzheimer’s and healthy brains and found APOE strongly upregulated in the microglia and perturbation in myelination-related processes in multiple cell types including oligodendrocytes.
Although foscarnet is widely used for HHV-6 encephalitis, it has never been specifically approved for HHV-6. Japan’s Ministry of Health, Labor and Welfare was the first to approve foscarnet (Foscavir) for the treatment of HHV-6 encephalitis.
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.
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.
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.
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.
A large prospective study in Africa adds weight to argument that HHV-6B infection is an important cause of febrile status epilepticus.
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