[Immunopathology of the inner ear]

Abstract

Immunologically mediated tissue lesions or functional disturbances can result from immune responses either to foreign antigens or autoantigenic constituents. Before a disease or a functional disorder can be called an (auto)immune disease, it must be established that immunological processes are involved in its etiology and/or pathogenesis. After reviewing the available data on immunology and on research on immunobiology of the inner ear, as well as clinical observations on disorders of the inner ear of possibly immunological origin, an attempt is made to determine whether (auto)immunopathology can be assumed in some patients with sensineural hearing loss. In patients with disorders presently recognized as autoimmune diseases, no hearing loss has been described so far. However, serum antibodies can be found via the indirect immunofluorescence method in some patients having functional disorders of the inner ear. These serum antibodies interact with normal human inner ear tissue. However, as long as immunopathological mechanisms have not been confirmed, these disorders should merely be called "diseases with autoimmune markers." It has been shown in animal experiments that the production of autoantibodies against inner ear components is associated with morphological and functional changes of the inner ear. The human endolymphatic sac releases secretory IgA into the lumen. Its epithelium contains (intraepithelial) lymphocytes, whereas lymphocytes, plasma cells (IgA, IgG) and macrophages occur in the perisaccular region. In this manner, the inner ear has its own immune system, which can possibly react independently of the systemic immune system.(ABSTRACT TRUNCATED AT 250 WORDS)