Idiopathic Sudden Sensorineural Hearing Loss and Cell-mediated Immunity.

In order to characterize the immunological mechanisms responsible for idiopathic sudden sensorineural hearing loss (ISSHL), changes in the ratio of the Tcell-subsets in the peripheral blood were investigated before and after treatment in 77 ISSHL patients who visited our clinic within 1 week from the onset of their ISSHL. Forty-three patients who had an average hearing ability of≥60dB before treatment (group I) received interferon therapy. Thirty-four patients who had an average hearing ability of≤59dB before treatment (group II) received steroid tapering therapy.Upon the first examination of many cases of from group I, a decreased number of whole lymphocytes, a decreased ratio of Tcells (CD3) in the lymphocytes population, especially CD4+Tcells (Helper T/Inducer Tcell), and a decreased ratio of CD4/CD8 cells were observed. After treatment in almost all cases from group I, the ratio of the Tcell-subsets recovered from these low levels to their CD4 dominant state. These changes in the ratios of the Tcell-subset were not observed in almost all of the cases in group II. Therefore, in ISSHL, there is a difference in cellmediated immune function according to the degree of hearing loss.These results suggest that one of possible etiologies for ISSHL is an immunological disorder caused by viral infection, etc.