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.
HHV-6 found to be the most frequent cause of viremia in children following HSCT
A prospective study of children transplanted for both malignant and nonmalignant disease found HHV-6 viremia in 53% of cases.
Evidence for HHV-6-induced thrombotic microangiopathy in transplant patients undergoing HSCT
Among infectious agents, HHV-6 was found to be an independent risk factor for thrombotic microangiopathy (TMA) and only HHV-6 infection was associated with TMA-related mortality.
Breakthrough reactivation of HHV-6 occurs with liver transplantation in spite of valganciclovir preemptive therapy for CMV
High-grade HHV-6 viremia is independently associated with rejection of liver transplants within 12 months
Adult patients with lower levels of anti-HHV-6 IgG are significantly more likely to experience HHV-6 reactivation following cord blood transplant
Patients with low levels of HHV-6 antibodies might benefit from treatment from IVIG or novel neutralizing antibodies before cord blood transplantation
Quantitative PCR of serum found superior to whole blood in differentiating between latent virus and viremia following cord blood transplantation
Use of serum more easily distinguishes viremia from latent virus
HHV-6 reactivation following haploidentical hematopoietic stem-cell transplant found to predict acute graft versus host disease in China
25% of the patients with HHV-6 reactivation developed aGVHD compared to 18% in those without reactivation.
Substantial reduction in hippocampal volume found in pediatric hematopoietic stem cell transplant patients with HHV-6B reactivation
Surprisingly, the damage from HHV-6B infection often occurred in the absence of obvious neurological symptoms. Patients without HHV-6 reactivation had no reduction in volume.
Telomeric integration, excision and subsequent and transmission in people with inherited chromosomally integrated HHV-6B (iciHHV-6B)
Exploiting a hypervariable region of the HHV-6B genome, investigators achieve new insights about integration, excision, and genomic stability of iciHHV-6B
Significantly worse outcomes in critically ill hematology patients associated with HHV-6 infection.
Two reports associate detectable HHV-6 DNA in body fluids with increased risk of mortality in patients being treated for hematologic malignancies.
HHV-6 is the predominant reactivated virus, other than CMV, in post-transplant cyclophosphamide associated infections
Large, retrospective multi-institutional study of non-CMV herpesvirus infection in the HCT with cyclophosphamide prophylaxis finds higher rate of HHV-6 infection and associated higher mortality
Failure to detect iciHHV-6 leads to overtreatment in hematopoietic cell transplant recipients
Mistaking iciHHV-6 for a marked reactivation of naturally-acquired infection can lead to unnecessary diagnostic procedures and treatments, with adverse effects.
Foscarnet prophylaxis improved engraftment and survival in cord blood transplant patients
Six-month overall survival was 96% in the treated group compared to 72% in the untreated group.
In DRESS/DIHS, early treatment with high dose steroids may suppress HHV-6; late treatment may prolong viremia
High dose steroids given in the first week appears to prevent HHV-6 reactivation in DRESS/DIHS patients by suppressing T-cell activation and serum interleukin-2 receptor (sIL-2R) levels. In contrast, a late start of steroid therapy resulted in a persistently high viral load for at least three weeks.
CMV & HHV-6 cause severe complications in non-transplant acute leukemia patients
Herpesvirus co-infections, particularly HHV-6 and CMV, cause severe lymphopenia, pneumonia, and an increased risk of acquiring bacterial and fungal infections in non-transplant acute leukemia patients undergoing chemotherapy.