In vitro studies confirm that the two viruses infect different cell types, and generate different cytopathic effects, cytokine and growth factor responses.
Two HHV-6 genes may contribute to pathogenesis of autoimmune thyroiditis
Genes U12 and U51 encode homologues of human G-protein-coupled receptors, and are potential triggers of autoimmunity.
Murine roseolovirus (MRV) infection experiments are only partially supportive of role of HHV-6A/B in Alzheimer’s disease
While MRV administered peripherally led to brain infection and neuroinflammation, it did not increase Aß deposition
HHV-6A promotes inflammation in astrocytoma cells by dysregulating autophagy
Infection increases ROS, induces ER stress and activates STAT3, NF-κB and mTOR pathways.
EBV and HHV-6 plasma viremia is infrequent at Day 7 during acute COVID-19
Other studies have suggested that reactivation of these viruses could theoretically contribute to a hyperinflammatory state or autoimmune disorders in acute COVID-19, but this study does not provide evidence of that.
Possible link between depression and HHV-6 infection in childhood
Serologic studies of several herpesviruses find that only HHV-6 may be linked to depression.
Does inherited chromosomal integration of HHV-6 at 9q increase the risk of malignancy?
A large study of iciHHV-6 integration sites found integration at 9q more common in hematologic malignancies—but the study lacked power to draw firm conclusions.
New seroepidemiological evidence that HHV-6 contributes to MS disease progression
Longitudinal study of people with a single initial episode of demyelination provides stronger evidence for HHV-6 than EBV in the pathogenesis of MS, but the evidence is not robust.
Development of highly sensitive technique for detecting viral DNA sequences in cell-free plasma
Isolating DNA fragments less than 120 base pairs enriches for viral vs. cellular DNA.
Resected tonsil and adenoid tissues harbor high viral loads of HHV-6, HHV-7 and EBV as well as respiratory viruses
HHV-6 was found in 33% of adenoid and 45% of tonsil tissues, with the highest rates found in younger children.
G-1082A polymorphism of IL-10 may protect against HHV-6/EBV adenoid hypertrophy
The presence of HHV-6 and EBV DNA in nasal secretions correlates with the degree of adenoid hypertrophy in children.
HHV-6A U14 protein and NFκB activate each other
The late protein U14 of HHV-6A can induce the pro-inflammatory transcription factor NFκB, and NFκB, in turn, can encourage the replication of HHV-6A.
Different isoforms of CD46 affect infectivity and replication of HHV-6A and HHV-6B
While CD134 remains the more important receptor for HHV-6B, HHV-6B can use the CD46 receptor when a T cell has the C1 isoform of CD46.
HHV-6B may enter cells that don’t express CD134 via the nectin-2 receptor
If confirmed, finding could explain ability of HHV-6B to infect salivary, liver and neural cells.
Adding an adoptive NK cell infusion to naïve T-Cell-depleted grafts may reduce the rate of HHV-6B reactivation and encephalitis
A small pediatric study found that adoptive NK cell infusions eliminated HHV-6B encephalitis, while maintaining a low rate of GVHD. At a ratio of NK/CD4 >2, the HHV-6B reactivation rate dropped dramatically.