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.
Human Herpesviruses-6A/6B linked to important reproductive diseases
A recent review from the Departments of Medicine and Obstetrics/Gynecology at Harvard Medical School and the University of Ferrara, Italy, summarizes evidence linking HHV6-A/B to several important reproductive diseases: primary unexplained infertility, preeclampsia, congenital infection and, possibly, spontaneous abortion and intrauterine growth restriction.
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
Levels of HHV-6B and HHV-7 DNA in saliva may distinguish people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome from healthy control subjects
Levels of HHV-6B and HHV-7 DNA in saliva were higher in people with ME/CFS than in health controls and tended to be higher at times symptoms were worse. Similar correlations were not seen for other human herpesviruses.
Mothers with iciHHV6 have an increased risk of spontaneous abortion
27.6% of Japanese mothers with iciHHV6 had a spontaneous abortion compared to 14.8% of controls. iciHHV6 mothers were also 6.4X more likely to have two or more spontaneous abortions.
HHV-6A/B in brain disease: proposed criteria for establishing causation
Three top experts on HHV-6A/B teamed up to write a comprehensive review and propose criteria for establishing HHV-6A/B to MS, epilepsy and Alzheimer’s disease.
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.
Japanese study supports evidence of iciHHV-6 reactivation in vivo
Surprisingly, 72% of integrated genomes were found on chromosome 22q. Solo-DR sequences of HHV-6B were left behind after excision and reactivation.
HHV-6A and the suppression of miR155 in Alzheimer’s pathology
Dysregulation of the microRNA miR155 is associated with pathophysiological progression of Alzheimer’s disease. HHV-6A has been shown to suppress miR155.
Latent HHV-6B infection of astrocytes may increase the risk of depression by activating the HPA axis
Japanese investigators show that a protein expressed by latent HHV-6B in astrocytes, results in an influx of extra-cellular calcium, triggering the onset of depression.
Fetal iciHHV-6 associated with a 3-fold increased risk of preeclampsia
A large UK study utilizing RNA sequencing metagenomics of placental samples identified HHV-6 RNA in 6.1% of pre-eclampsia cases and 2.2% of healthy pregnancies. HHV-6 was the only virus found and it was iciHHV-6 in 70% of cases.