Detection of HHV-6 and EBV and Cytokine Levels in Saliva From Children With Seizures: Results of a Multi-Center Cross-Sectional Study

Abstract

Background and Objective: One third of children with epilepsy are refractory to medications. Growing data support a role of common childhood infections with neurotropic viruses and inflammation in epileptogenesis. Our objective was to determine the frequency of Human Herpesvirus-6 (HHV-6) and Epstein-Barr Virus (EBV) infection and cytokine levels in saliva from children with seizures compared to healthy controls and to controls with a febrile illness without seizures.Methods: In this cross-sectional multi-center study, we collected saliva from 115 consecutive children with acute seizures (cases), 51 children with a fever and no seizures or underlying neurological disease (fever controls) and 46 healthy children (healthy controls). Specimens were analyzed by a novel droplet digital PCR for HHV-6 and EBV viral DNA and a bead-based immunoassay for neuroinflammatory cytokines.Results: Cases included febrile seizures (n = 30), acute seizures without (n = 53) and with fever (n = 4) in chronic epilepsy, new onset epilepsy (n = 13), febrile status epilepticus (n = 3), and first lifetime seizure (n = 12). HHV-6 DNA was found in 40% of cases vs. 37% fever controls and 35% healthy controls, with no statistically significant differences. EBV DNA was also detected with no differences in 17% cases, 16% fever controls, and 28% healthy controls. IL-8 and IL-1β were increased in saliva of 32 random samples from cases compared with 30 fever controls: IL-8 cases mean (SD): 1158.07 pg/mL (1427.41); controls 604.92 (754.04); p = 0.02. IL-1β 185.76 (230.57); controls 86.99 (187.39); p = 0.0002. IL-1β level correlated with HHV6 viral load (p = 0.007).Conclusion: Increase in inflammatory cytokines may play a role in the onset of acute seizures and saliva could represent an inexpensive and non-invasive method for detection of viral DNA and cytokines.

Differential Activation of Neuroinflammatory Pathways in Children with Seizures: A Cross-Sectional Study

“…Several studies have shown that this cytokine is increased after seizures, including focal, generalized tonic-clonic, myoclonic, atypical absence, and typical absence seizures in serum and CSF of patients with epilepsy. [39][40][41] In a previous study 24 found higher levels of this cytokine in saliva from children with epilepsy but this time we could not confirm this finding in the same biological compartment.…”

“…21,22 IL6-mediated cellular and humoral immune responses play a crucial role in determining the outcome of viral infection. 23 In a preliminary feasibility study, 24 we showed higher levels of IL8 and IL1β in saliva from 32 children with seizures compared to 30 age-matched controls with a febrile illness and no seizures.…”

Differential Activation of Neuroinflammatory Pathways in Children with Seizures: A Cross-Sectional Study

“…Several studies have shown that this cytokine is increased after seizures, including focal, generalized tonic-clonic, myoclonic, atypical absence, and typical absence seizures in serum and CSF of patients with epilepsy. [28][29][30] In a previous study 7 we found higher levels of this cytokine in saliva from children with epilepsy but this time we could not confirm this finding in the same biological compartment.…”

Viral infections and their relationship to neurological disorders

“…One hypothesis suggests that common childhood viral infections can generate acute and chronic inflammatory processes in the CNS, which increases BBB permeability and neuronal excitability [ 103 ]. Acute seizures and epilepsy have been linked to HHV-6 infections, especially in children [ 104 ]. The number of HHV-6 infections associated with mesial temporal or temporal lobe epilepsy range from 9.1% to 55.6% [ 5 , 105 ].…”