Human herpes simplex virus-6 (HHV-6) detection and seroprevalence among Qatari nationals and immigrants residing in Qatar

Symptomatic central nervous system tuberculosis and human herpesvirus-6 coinfection with associated hydrocephalus managed with endoscopic third ventriculostomy: A case report and review of human herpesvirus-6 neuropathology

Background

Human herpesvirus 6 (HHV-6) is a double-stranded DNA virus well established in the clinical literature to cause the near-universal childhood infection roseola infantum (exanthema subitum/sixth disease). Primary HHV-6 infection has been reported to cause meningoencephalitis in pediatric patients, although generally in the immunocompromised.

Case Description

The authors treated an immunocompetent 18-month-old female who transferred to our institution for a higher level of care given concerns for meningitis in the setting of decreased level of arousal (Glasgow Coma Scale 12), and bradycardia 9 days after the onset of nasal congestion, fatigue, and repeated bouts of emesis. Outside hospital cerebrospinal fluid (CSF) studies were notable for hypoglycorrhachia, elevated protein, elevated nucleated cells with a mononuclear predominance, and a meningitis polymerase chain reaction panel that was positive only for HHV-6. Brain magnetic resonance imaging with and without contrast revealed a basal cistern predominant leptomeningeal enhancement pattern as well as moderate ventriculomegaly with associated periventricular edema concerning acute communicating hydrocephalus. Considering the CSF studies, neuroimaging, and recent travel history to Mexico, central nervous system (CNS) tuberculosis (TB) was the leading suspicion, and antimicrobial therapy was initiated for this presumptive diagnosis with culture data only proving the TB suspicion correct after nearly 2 months in culture. Anti-viral therapy was initially not felt to be necessary as the HHV-6 was interpreted as incidental and not a cause of symptomatic meningitis in our immunocompetent host. The patient's hydrocephalus was treated with temporary CSF diversion followed by performance of an endoscopic third ventriculostomy. Despite appropriate hydrocephalus management, clinical improvement ultimately seemed to correlate with the initiation of antiviral therapy.

Conclusion

The authors present this case and review the literature on HHV-6-associated CNS infections with the goal of informing the neurosurgeon about this often clinically underestimated pathogen.

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Pan-viral serology uncovers distinct virome patterns as risk predictors of hepatocellular carcinoma and intrahepatic cholangiocarcinoma

This study evaluates the pan-serological profiles of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) compared to several diseased and non-diseased control populations to identify risk factors and biomarkers of liver cancer. We used phage immunoprecipitation sequencing, an anti-viral antibody screening method using a synthetic-phage-displayed human virome epitope library, to screen patient serum samples for exposure to over 1,280 strains of pathogenic and non-pathogenic viruses. Using machine learning methods to develop an HCC or iCCA viral score, we discovered that both viral scores were positively associated with several liver function markers in two separate at-risk populations independent of viral hepatitis status. The HCC score predicted all-cause mortality over 8 years in patients with chronic liver disease at risk of HCC, while the viral hepatitis status was not predictive of survival. These results suggest that non-hepatitis viral infections may contribute to HCC and iCCA development and could be biomarkers in at-risk populations.

The Association of HHV-6 and the TNF-α (-308G/A) Promotor with Major Depressive Disorder Patients and Healthy Controls in Thailand

Major depressive disorder (MDD) is a silent global health problem that can lead to suicide. MDD development is suggested to result from numerous risk factors, including genetic factors. A precise tool for MDD diagnosis is currently not available. Recently, inflammatory processes have been identified as being strongly involved in MDD development and the reactivation of human herpesvirus type 6 (HHV-6), upregulating cytokines such as TNF-α, which are associated with MDD. Therefore, this study aimed to determine the association of HHV-6 with genetic factors, especially TNF-α mutation, in MDD patients and their relatives compared to healthy controls. The Patient Health Questionnaire (PHQ-9) was used to evaluate MDD status, and 471 oral buccal samples were investigated for HHV-6 infection and viral copy number by qPCR. TNF-α (-308G/A) gene mutation and the cytokines TNF-α, IL-6, and IL-10 were analyzed by high-resolution melting (HRM) analysis and enzyme-linked immunosorbent assay (ELISA). Whole-exome sequencing of buccal samples was performed to analyze for genetic factors. The results showed significantly higher HHV-6 positivities and viral loads in MDD patients (15/59 (25.67%) and 14,473 ± 16,948 copies/µL DNA) and their relatives (blood relatives 17/36 (47.22%) and 8146 ± 5656 copies/µL DNA); non-blood relatives 7/16 (43.75%) and 20,721 ± 12,458 copies/µL DNA) compared to the healthy population (51/360 (14.17%) and 6303 ± 5791 copies/µL DNA). The TNF-α (-308G/A) mutation showed no significant difference. Surprisingly, 12/26 (46.15%) participants with the TNF-α (-308G/A) mutation showed HHV-6 positivities at higher rates than those with wild-type TNF-α (-308G) (70/267 (26.22%)). HHV-6-positive participants with TNF-α (-308G/A) showed higher levels of TNF-α, IL-6, and IL-10 than those of negative control. Exome analysis revealed that common mutations in immune genes were associated with depression. Therefore, this study unveiled the novel association of inflammatory gene TNF-α (-308G/A) mutations with HHV-6 reactivation, which could represent a combined risk factor for MDD. This result could induce further research on MDD development and clinical applications.