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.
Viral reactivation may be one cause of febrile neutropenia in chemotherapy patients
HHV-6 was the most prevalent virus in febrile neutropenia episodes among pediatric patients
The effects of HHV-6B infection on immune checkpoint inhibition
HHV-6B infection of primary monocytes induces cell-associated and soluble PD-L1 production, increased intracellular ROS and activation of STAT1 and STAT3 pathways
HHV-6 linked to intrauterine growth restriction via the human leukocyte antigen-G dysregulation
A small study found a strong association between HHV-6 infection of the placenta and intrauterine growth restriction—a finding consistent with other evidence linking HHV-6 to several reproductive diseases.
HHV-6A and 7 infection of T cells downregulates the protein tyrosine phosphatase, CD45
CD45, important in T cell receptor signaling, may be one mechanism by which roseolaviruses evade immune detection and help achieve latency
iciHHV-6 may modulate human gene expression
A Japanese group found that ciHHV6 genes encoding for immunoglobulins were decreased in ciHHV6 individuals, possibly modulating immune responses.
HHV-6A, HHV-6B, and HHV-7 have differential impact on intracellular DNA sensors of NK cells
Cytokine and chemokine responses were very similar in HHV-6B and HHV-7 infections. The results were starkly different for HHV-6A.
49 new CD4 T-cell-recognized HHV-6B antigens identified using genome-wide approach
University of Washington investigators utilized rare cell enrichment and an HLA-agnostic, proteome-wide approach to expand the library of known HHV-6 T cell antigens from 11 to 60.
New HLA-DR3-restricted HHV-6B peptides demonstrate broadly recognized polyfunctional and cytotoxic CD4 T-cell responses
University of Massachusetts investigators have identified 25 new naturally processed peptide sequences using mass spectrometry.
HHV-6 infection induces a high percentage of virus-specific suppressive Tregs compared to CMV
A French group studied immunological responses to HHV-6 and CMV in healthy adults ex vivo and found that HHV-6 induces an excessive number of potently immunosuppressive T regulatory cells that block dendritic cell maturation and functions.
An elevated CD134/CD4+ ratio before conditioning results in a 10 fold increased risk of HHV-6B reactivation
A prospective study of allogenic stem cell transplant patients in Japan suggests that the percentage of CD134+ T cells could be used to predict which patients are vulnerable to HHV-6 reactivation. The authors propose that further investigation into the effect of elevated CD134+ T cells pre-transplant is warranted.
Breakthrough on therapeutic HHV-6B neutralizing antibodies
Yasuko Mori and colleagues were successful in humanizing two neutralizing monoclonal antibodies to HHV-6B. The chimeric antibodies performed well enough to show promise for therapeutic use.
Virus specific donor T cells found effective in treating HHV-6 and other viruses in Phase II clinical trial
“Off-the-shelf” donor T cells primed to fight five specific viruses were shown to be effective in a Phase 2 trial backed by Viracyte. A single infusion produced a complete or partial response rate of 92%.