Cryptogenic epilepsy: An infectious etiology?

Purpose: Cryptogenic epilepsy, the group of epilepsy syndromes for which an etiology is unknown, comprises similar to 20% of all epilepsy syndromes. W e selected patients in this subgroup of epilepsy and tested them for eviden ce of Toxoplasma gondii IgG antibodies by the enzyme-linked immunosorbent a ssay. T. gondii is found in up to 20% of the U.S. population forming dorman t brain cysts in the latent bradyzoite form. We investigated the hypothesis that dormant T. gondii infection might be associated with cryptogenic epil epsy. Methods: We selected patients with cryptogenic epilepsies and tested them f or evidence of T. gondii IgG antibodies by the enzyme-linked immunosorbent assay. A control group was also tested for comparison. Results: We have found a statistically-significant elevation of T. gondii a ntibodies among cryptogenic epilepsy patients as compared to controls [59% increase in optical density (OD), p = 0.013]. This association persisted af ter adjustment for subjects' gender and age in a multiple logistic regressi on model; however, it was no longer as statistically significant. Conclusions: Our results suggest that chronic T. gondii infection with brai n cysts may be a cause of cryptogenic epilepsy.