The Optic Neuromyelitis is an inflammatory and autoimmune illness of the central nervous system. Presently work is carried out a revision of the different mechanisms involved in the pathogenesis of the Optic Neuromyelitis, the paper of the eosinophils is analyzed, of the antibodies against own antigens and of the regulatory T cells in the illness. In the Optic Neuromyelitis is very important the humoral response, the illness exists it is characterized by the immunocomplex deposit, activation of the complement, production of antibodies against proteins of the myelin and eosinophils recruitment in the lesions. It also exists an increase of the expression of chemokines receptors like the CCR3, specific of TH2 cells; the illness is associate predominantly to a TH2 response.