Viruses and the immune system: role in seizure development

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J Neurochem. 2008 Jan 17 [Epub ahead of print] Viruses and the immune system: their roles in seizure cascade development.Getts DR,... The Discipline of Pathology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia.Viral

encephalitis affects approximately 7.5 people/100 000 and carries a

high rate of morbidity and mortality. Most patients with viral

encephalitis will develop some form of seizure during the infectious

process, and of those who survive encephalitic disease, approximately

4-20% will develop epilepsy. Arthropod-borne (arbo)viruses are the

leading cause of viral encephalitis in the world today, with between

10% and 35% of patients infected with these viruses displaying some

form of seizure. Several neurotropic DNA viruses, including Herpes and

cytomegalovirus also commonly cause seizures in infected patients. In

the clinical setting, the cause of seizures seen during viral

encephalitis is usually attributed to acute febrile responses. However,

it has become apparent that the mechanisms behind seizure generation

during viral encephalitis are likely to be much more complicated. For

example, CD4(+) and CD8(+) T cells possibly through their secretion of

interferon-gamma, appear to play an important role in determining

neuronal responses when challenged with kainic acid. In addition, the

ability of the human immunodeficiency virus, transactivating protein to

modulate NMDA signaling possibly triggering seizures, highlights the

fact that elements of the antiviral response and even virally derived

proteins are capable of directly manipulating neuronal function.

Understanding the complex relationships between the CNS, the immune

system, and invading pathogens is a critical step in understanding the

pathogenesis of seizures seen during viral infections and informing the

development of novel therapies.PMID: 18205751 [PubMed - as supplied by publisher]