The Expression of TNFα, IL-6, IL-2 and IL-8 in the Serum of Patients with Idiopathic Sudden Sensorineural Hearing Loss: Possible Prognostic Factors of Response to Corticosteroid Treatment

Abstract

<b><i>Introduction:</i></b> Idiopathic sudden sensorineural hearing loss (ISSNHL) remains one of the major unsolved otologic emergencies. A viral infection, a systemic inflammatory disorder, as well as physical, mental and metabolic stress can trigger an innate immune response in the inner ear resulting in ISSNHL. Proinflammatory cytokines play a central role in this cochlear immunological cascade. <b><i>Objective:</i></b> To examine the expression of proinflammatory cytokines in the serum of patients with ISSNHL in correlation with the therapeutic outcome of intravenous administration of corticosteroids. <b><i>Method:</i></b> Forty-three patients primarily diagnosed with ISSNHL underwent intravenous corticosteroid treatment for 8 days. The expression of tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), interleukin-2 (IL-2) and interleukin-8 (IL-8) was detected with the use of enzyme-linked immunosorbent assay in serum specimens on the 1st and 8th day of treatment and it was correlated with the treatment outcome. <b><i>Results:</i></b> TNFα reduction and IL-6 increase strongly correlate with a good therapeutic result [χ<sup>2</sup>(2) = 13.12, p = 0.001 and χ<sup>2</sup>(2) = 16.78, p = 0.0001]. IL-8 increase reflects negatively on the outcome, however, not in a statistically significant way. No association was established between IL-2 variations and the therapeutic outcome. <b><i>Conclusions:</i></b> TNFα and IL-6 can be used as prognostic factors for the treatment outcome, whereas the prognostic value of IL-8 requires further statistical confirmation.