High frequency of T helper type 9 cells in Chinese patients with allergic rhinitis.

Background: T helper type 9 cells (Th9) are the most recently discovered subset of Th cells, and are involved in the pathology of several autoimmune and allergic diseases. The significance of Th9 cells in allergic rhinitis (AR) in Chinese patients is unclear.

Objective: The aim of this study was to investigate the possible role of Th9 cells in AR in Chinese patients.

Methods: Th9 cells and related factors were assessed by measuring levels of interleukin-9 (IL-9), PU.1, interferon-regulatory factor 4 (IRF4), and numbers of Th9 cells. A Th9-polarized milieu was evaluated by determining the levels of IL-4 and transforming growth factor-β1 (TGF-β1). Disease severity was assessed by rhino-conjunctivitis quality of life questionnaires (RQLQ), visual analog scale scores (VAS), and peripheral eosinophils (EOS) count.

Results: Levels of IL-4 and TGF-β1 were elevated in AR groups versus healthy controls (P < 0.05). Levels of IL-9, PU.1, IRF4, and the numbers of Th9 cells were also significantly higher in the AR groups (P < 0.05). Furthermore, positive correlations were identified between IL-9 levels and EOS expression, RQLQ, and VAS scores (P < 0.01).

Conclusions: Th9 cells and their relative factors were elevated in AR patients. Levels of Th9 polarization-related factors were much higher in AR patients, and the severity of disease was associated with a more severe Th9 response. These results suggest that AR patients present a favorable environment for Th9 differentiation, and that Th9 cells may play a crucial role in the pathology of AR in Chinese patients.