Markers of neurotoxicity: from behavior to autoantibodies against brain proteins.

Evidence of potentially neurotoxic exposures may be obtained in peripheral indicator media, but molecular or cellular evidence of neurotoxic effects has not been as readily available, primarily because the nervous system of living humans is beyond the reach of direct measures. Although there is limited evidence that molecular changes in the blood can provide information about neurotoxicity, several new approaches are being investigated. One is that the immune system may preserve evidence of damage to the nervous system. Debris from damaged cells in the nervous system may present as antigens, giving rise to autoantibodies, which may be detectable in blood for a long time after injury. Progress will depend on more control experiments and clarification of confounding variables. Validation of new molecular markers must go hand in hand with documentation of impaired function, most commonly measured as behavioral or neurophysiological changes. These noninvasive markers will be measured with greater sensitivity and precision, thanks to innovative computer technology. The practical advantages of the new markers may be as important as their contribution to our understanding of the mechanisms by which the nervous system defends against chemical insult.