In vitro studies confirm that the two viruses infect different cell types, and generate different cytopathic effects, cytokine and growth factor responses.
While MRV administered peripherally led to brain infection and neuroinflammation, it did not increase Aß deposition
Infection increases ROS, induces ER stress and activates STAT3, NF-κB and mTOR pathways.
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.
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.
Isolating DNA fragments less than 120 base pairs enriches for viral vs. cellular DNA.
The presence of HHV-6 and EBV DNA in nasal secretions correlates with the degree of adenoid hypertrophy in children.
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.
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.
If confirmed, finding could explain ability of HHV-6B to infect salivary, liver and neural cells.
Pattern consistent with clinical studies suggesting these viruses may be one trigger of systemic sclerosis.
A viral miRNA disrupts mitochondrial architecture, suppresses type I interferon production, is necessary for productive infection and for virus reactivation, all by inhibiting multiple members of the host miR-30 family—creating a therapeutic target to suppress reactivation.
Chromatin interactions help silence transcription of HHV-6A genes following integration
HHV-6B infection of primary monocytes induces cell-associated and soluble PD-L1 production, increased intracellular ROS and activation of STAT1 and STAT3 pathways
The combination of gQ1 and gQ2 tetramer components of both HHV-6A/6B are important for viral propagation, probably by affecting attachment to their different receptors.