Abstracts

Rationale: There is growing evidence that epileptic seizures can result in changes in immunologic parameters and that immunologic processes may influence the course of epilepsies vice versa. Along with these findings, there are several hints that antiepileptic drugs could influence the immune system. Therefore, we performed a prospective study on the influence of valproate and levetiracetam on immune parameters. Methods: 36 patients were included. 15 patients were started on valproate (10 (66,7%) male, 5 (33,3%) female, age 53,5 ± 27,2 years), 21 were started on levetiracetam (11 (52,4%) male, 10 (47,6%) female, age 44,7 ± 19,4 years) at the discretion of the treating physician. Immunologic parameters were examined before first intake of the new drug and 6 months later. We performed a differential blood count and analyzed the distribution of CD3+CD4+- and CD3+CD8+-leukocyte subsets using flow cytometry. Levels of IL-1β, IL-6, TNF-α and MCP-1 were studied using ELISAs. Results: Valproate intake resulted in a significant decrease of the total number of leukocytes (6.96 ±1.23/nl versus 6.13 ± 1.57/nl, p=0.026). The absolute count (4.60 ± 1.05/nl versus 3.69 ± 1.30/nl, p=0.01) and percentage (65.39 ± 7.86% versus 59.54 ± 11.47% p=0.01) of neutrophil granulocytes dropped significantly. Lymphocyte subset analyses revealed a significant decrease of the percentage of CD3+CD4+ -lymphocytes from 50.93 ± 10.23% to 45.72 ± 12.15% (p=0.003). These changes resulted in a non-significantly lowered CD4/CD8 ratio (3.54 ± 2.00 versus 3.06 ± 2.28 p=0.1). Comparison of cytokine-levels at baseline- and follow-up conditions did not show any significant changes. Intake of levetiracetam did not go along with any significant changes in leukocytes, neutrophil granulocytes, lymphocytes or lymphocyte subsets. We did not see any significant alterations in cytokine concentrations although there was a trend towards decreased MCP-1 levels (p=0.09). Conclusions: Valproate reduced levels of leukocytes and lowered CD3+CD4+-lymphocytes in this prospective study, confirming previous retrospective reports. Lowered counts of CD3+CD4+-lymphocytes could be due to an increase of apoptosis in these cells. We did not see any significant changes associated with intake of levetiracetam.