ステロイド依存性感音難聴における血清免疫学的検査所見

抄録

In recent years, we have identified certain patients with idiopathic sensorineural hearing loss for whom acute progression of the disease in one or both ears was found to be responsive to steroid administration, and for whom any recovery of hearing function thus obtained could be manintained with long term steroid administration. We named it as steroid-responsive sensorineural hearing loss. Although the pathological mechanism of sensorineural hearing loss in such patients is not as yet understood, it is possible that autoimmune disease may play a role. To investigate this possibility, studies of cellular and serological immune function were conducted for 14 patients with steroidresponsive sensorineural hearing loss or idiopathic progressive sensorineural hearing loss, including assays for immunoglobulins, lymphocyte subsets, complement, circulating immune complexes and specific autoantibodies.
Quantitative assessment of immunoglobulin levels was found to be manifestly abnormal in 5 out of 10 patients (50.0%) for whom such studies were carried out. Additionally, abnormalities in ratios of various lymphocyte subsets were identified in 7 out of 14 patients (50.0%) for whom lymphocyte subsets were assessed. More particularly, several patients demonstrated depressed ratios of suppressor T cells which are known to permit or induce B cell activation, although there was no clear correlation of measured immunoglobulin level with abnormalities in suppressor T cells ratios.
While there was an increased incidence of some type of immunological abnormality in the patients we studied, no obvious trend or pattern in abnormal immunological functions was identified. This may be attributable to the small number of patients studied, variation in the stage or duration of disease, as well as to variables pertaining to treatment, for example, dosage and/or duration.