[Immuno-pathogenesis in Meniere's disease]

Bilateral progressive hearing loss and vestibular dysfunction with inner ear antibodies

Autoimmune inner ear disease (AIED) is a clinical syndrome of uncertain etiology. We present the neuro-otological findings of 2 cases of bilateral hearing loss, dizziness and the antibody profiles of the inner ears. Case 1 had bilateral progressive hearing loss, vestibular dysfunction and abnormal eye movement as the disease progressed. She had inner ear antibodies against 42 and 58kDa protein antigency on Western blot immune assay, and responded to glycocorticosteroid but not to immunosuppressant treatment. Intratympanic steroid injection temporally eliminated her symptoms. However, she developed idiopathic Cushing's syndrome and underwent labyrinthectomy. Case 2 became deaf as a teenager and experienced dizziness 10 years after becoming deaf. He reacted strongly to 68kDa protein and was a good responder to immunosuppressant with steroid. As we still lack a definitive diagnostic test for AIED, careful observation of the clinical course is critical for differential diagnosis regarding the bilateral progressive hearing loss.

Distribution and immunoregulatory properties of antisecretory factor

Inflammatory processes and the mechanisms by which they are initiated and controlled within the central nervous system (CNS) involve a vast array of cell types and molecules. One cell type believed to be involved in the control of inflammation in the CNS is the microglial cell. The TLD antibodies are a panel of monoclonal antibodies reactive to rat microglial antigens. One antibody from this panel, clone TLD-1A8A, is specific for antisecretory factor (ASF). ASF is a previously identified protein characterized as a potent inhibitor of enterotoxin-induced intestinal fluid secretion. Our results extend the function of this molecule to include the regulation of immune reactions. Administration of TLD-1A8A to T-cell proliferation or mixed leukocyte response assays resulted in increased proliferation of T cells. Flow cytometric analysis indicates that ASF is expressed on macrophages, B cells and dendritic cells, but not on T cells or granulocytes. Immunohistochemical analysis indicates that ASF is expressed by macrophages and cells of dendritic morphology in the spleen, thymus, lymph nodes, Peyer's patch, and in the perivascular area in the CNS. Furthermore, Western blot analysis indicates that ASF is expressed in many tissues including all secondary lymphoid organs. These data suggest that ASF may have a previously unsuspected role in regulating the immune system.