Clinical Relevance of IL-17 during SLIT on AR to HDM

Abstract

Objective: To investigate the clinical relevance of serum IL-17 levels in AR patients treated with sublingual immunotherapy (SLIT) to identify the function of TH17 cells and IL-17 in AR.

Method: The patients with AR to HDM starting to receive SLIT in Seoul National University Hospital between June 2008 and August 2010 were enrolled. We detected serum IL-17 levels via ELISA before and 1 and 2 years after starting SLIT. Symptom diaries, rescue medication use, and other immunological parameters were analyzed.

Results: Longer onset of symptoms and moderate to severe symptoms were significantly related to higher serum IL-17 levels before starting SLIT. HDM-specific IgE significantly increased between the baseline and the first year of SLIT, while HDM-specific IgG4 had no significant change. There was a significant positive correlation between serum ECP and IL-17 levels during SLIT. The changes of serum IL-17 and total IgE levels for 1 year had an inverse relationship with the effectiveness of SLIT. Changed serum IL-17 levels at the first year was the most significant factor in relation to the effectiveness of SLIT by multivariate analysis.

Conclusion: Serum IL-17 levels in AR correlated with duration from symptom onset, symptom severity, and serum ECP levels. Changes of serum IL-17 levels during SLIT are expected to be a prognostic factor to predict the effectiveness of SLIT. Thus, IL-17 and TH17 cells might have an important role in AR pathogenesis.