S100B proteins in febrile seizures.

S100B protein concentrations correlate with the severity and outcome of brain damage after brain injuries, and have been shown to be markers of blood-brain barrier damage. In children elevated S100B values are seen as a marker of damage to astrocytes even after mild head injuries. S100B proteins may also give an indication of an ongoing pathological process in the brain with respect to febrile seizures (FS) and the likelihood of their recurrence. To evaluate this, we measured S100B protein concentrations in serum and cerebrospinal fluid from 103 children after their first FS. 33 children with acute infection without FS served as controls for the serum concentrations. In the FS patients the mean S100B concentration in the cerebrospinal fluid samples was 0.21 μg/L and that in the serum samples 0.12 μg/L. The mean serum concentration in the controls was 0.11 μg/L (difference 0.01 μg/L, 95% confidence interval -0.02 to 0.04 μg/L, P = 0.46). There was a correlation between age and serum S100B concentration (r = -0.28, P = 0.008) in children under four years, but S100B concentrations did not predict the clinical severity of the FS nor their recurrence. There was no correlation between time of arrival at the hospital after FS and S100B concentration in serum (r = -0.130, P = 0.28) or in cerebrospinal fluid samples (r=-0.091, P = 0.52). Our findings indicate that FS does not cause significant blood-brain barrier openings, and increase the evidence that these seizures are relatively harmless for the developing brain.