Do neurological signs occur in experimental allergic encephalomyelitis in the absence of inflammatory lesions of the central nervous system?.

Guinea pigs with paralysis or other severe neurological signs of experimental allergic encephalomyelitis (EAE) always exhibited typical histological inflammatory lesions. A few animals inoculated with either the encephalitogenic emulsion or only the control adjuvant emulsion had mild weakness or slowness but no histologic lesion. In some instances, these signs were explained by coincidental non-neural disease or trauma. Therefore, such mild clinical signs cannot be considered pathognominic of EAE. Reports from the literature suggesting that animals have developed clinical signs without histological lesions in EAE are considered invalid because of the nonspecificity of clinical signs, the occurrence of intercurrent diseases, the inadequacy or incorrect timing of histologic evaluations, and the lack of controls for specificity of the signs. There is no basis for the supposition that autoimmunity can cause major neurological signs in the absence of inflammatory lesions in the nervous system.