[Morphological changes of the thymus and spleen with acute experimental allergic encephalomyelitis (EAE) in Lewis rats].

Nervous and immune systems are thought to have an important role in host defence mechanism. Recent reports have suggested the presence of common antigens between nervous and immune systems. In this paper, we described the interactions between nervous and immune systems observed in an acute EAE model of Lewis rats. Seventeen Lewis rats were immunized by homogenized brain tissue in complete Freund adjuvant. Acute EAE rats were developed in 10 rats, all of which died within 25 days after the immunization. The thymus of these rats showed marked atrophy and histological examination revealed severe de generation of the lymphocytes and infiltration of macrophage showing phagocytosis in the thymus. The weight of spleen was also decreased, but no remarkable changes were observed microscopically except slight reduction of the white pulp. The fact that the immune reactions was induced not only in the nervous system but also in the thymus of EAE animals may suggest the possibility of common antigen between oligodendroglia and lymphocytes. This also suggest the close interaction between nervous system and immune system. However, the reactions of the thymus and spleen were different in this experiment, and further studies are necessary to evaluate the mechanism of these immune reactions.