HHV-6 & MTLE in China
Mesial temporal lobe epilepsy brain tissue found to have HHV-6B DNA and elevated NF-κB expression. Dr. Li and colleagues from China have found that 28% of refractory epilepsy patients have high levels of HHV-6B DNA in their brain tissues when they have brain resections as a last resort to halt seizures. This study confirmed several earlier findings, including a 2007 study by NINDS investigators (Fotheringham 2007a). The Chinese group used immunohistochemistry, real time PCR and other techniques to demonstrate that the HHV-6 was found in the same cell locations as NF-κB, a key transcription factor associated with inflammatory responses. The subset of patients found with HHV-6-positive DNA had a history of febrile convulsions. Read Abstract.
HHV-6 & MTLE in Germany
HHV-6 DNA found in majority of epilepsy patients with a history of encephalitis. Niehusmann and colleagues from Germany found HHV-6 DNA in over 55% of the temporal lobe epilepsy patients with a history of encephalitis, and none of the controls, using nested PCR. Unlike the Li and Fotheringham studies featured above, they did not find HHV-6B in the subset of patients with a history of febrile seizures. The difference may be due in part to the fact that the Li and Fotheringham studies analyzed fresh rather than stored tissues. Read Abstract
HHV-6 in Febrile Status Epilepticus in USA
The FEBSTAT Study
Drs. Shinnar and Epstein at Northwestern University conducted a prospective study of the consequences of prolonged febrile seizures (FEBSTAT), which determined the frequency of HHV-6 and HHV-7 infection as a cause of febrile status eptilepticus (FSE). Of the 119 children (ages 1 month to 5 years old) enrolled after presenting with FSE, HHV-6B viremia was found in 31% and HHV-7 viremia was found in 7% of patients at baseline. Together, they account for one-third of FSE, a condition associated with an increased risk of both hippocampal injury and subsequent temporal lobe epilepsy. The FEBSTAT study is ongoing and the investigators have not yet published this data.