Abstracts

Rationale: Primary infection with HHV-6B is associated with febrile status epilepticus and may also play a role in chronic epilepsy, as demonstrated by studies that showed HHV-6B DNA in specimens of patients with mesial temporal sclerosis and focal cortical dysplasia. Similarly, EBV has been associated with acute seizures in children. We aimed to determine if viral infections may be linked with acute seizures and epilepsy in children. Methods: Inclusion criteria are: age 1 month - 18 years, presentation with acute seizures, either isolated or multiple of any duration, with or without a fever or a diagnosis of epilepsy. Exclusion criteria are: pregnancy, current treatment with immunosuppressive agents or prior diagnosis of primary or acquired immunodeficiency. Controls will be age-matched children who present to the ER for a fever. Collected biological specimens include saliva, blood and CSF (when available). DNA was extracted using a DNeasy Blood and Tissue Kit (Qiagen, Valencia, CA) according to the manufacturer's instructions. We utilized digital droplet PCR (ddPCR) for absolute quantification of target DNA molecules and detection of HHV-6A, HHV-6B and EBV. Droplet positivity was determined by fluorescence intensity; only droplets above a minimum amplitude threshold were counted as positive. Negative control DNA and a no template control were included in each experiment and resulted in zero positive droplets. Results: 30 patients were enrolled. Saliva was collected in 29 patients, blood in 11 patients and CSF in 1 patient. Eight saliva samples had to be discarded due to insufficient quantity for DNA extraction. Median age was 5 years (range 9 months ?" 16 years). 14 patients had acute seizures in the context of epilepsy: HHV-6B was detected in saliva of 4 of these patients, and EBV in one. 5 patients had a febrile seizure and we detected HHV-6B in saliva from 2 of them. Two patients had new onset of epilepsy, 3 patients had a first unprovoked seizure and 1 patient had Febrile Infection-Related Epilepsy Syndrome (FIRES), all with negative ddPCR results. 50% of patients (n=3) who tested positive for HHV-6B had a fever. Conclusions: In this preliminary study, we detected HHV-6B in 29% of patients with acute seizures and 21% of total patients whose biological samples were analyzed. These data support the hypothesis that HHV-6B may be implicated in the pathogenesis of seizures in children and will require confirmation and comparison with controls and larger series. Funding: The authors report internal funding from the Center for Neuroscience.