Regulatory-T, T-helper 1, and T-helper 2 Cell Differentiation in Nasal Mucosa of Allergic Rhinitis with Olive Pollen Sensitivity

Background: Allergic rhinitis (AR) is a disease in which T-helper (Th)2 response is predominant and its pathogenic mechanism is still poorly understood.

Aim: To evaluate the possible role of Th1, Th2 and regulatory-T (Treg) cells in the pathogenesis of AR.

Methods: This case-control study enrolled 41 patients with seasonal AR (10-62 years old), sensitive to olive pollens, and 15 healthy controls (18-60 years old). Nasal biopsy was performed and specimens of nasal lavage fluid were obtained from all participants. The levels of interleukin (IL)-4, IL-10, interferon (IFN)-γ and transforming growth factor-β (TGF-β) were measured in nasal lavage fluid specimens. The expression of FOXP3, GATA-3 and T-bet was measured by immunohistochemical methods in the nasal biopsy specimens.

Results: The levels of IFN-γ in the group with AR were significantly lower than those in the control group (p = 0.008). The levels of IL-4, IL-10 and TGF-β did not differ between the two groups. The expression of FOXP3 and T-bet in patients with AR was significantly lower than that in the control group (both p = 0.001). Expression of GATA-3 in the nasal mucosa was similar between the groups (p = 0.2). The ratios of T-bet/GATA-3 and FOXP3/GATA-3 in the AR group were significantly lower than those in the control group (p = 0.001).

Conclusion: Insufficient Treg and Th1 cells may be associated with the allergic inflammation that may be attributed to the Th2 immune response in patients suffering from AR who are sensitive to olive pollen.