Expression and significance of CCR6 in regulatory T cells and eosinophils in allergic rhinitis

  Background  In recent years, many studies have shown that chemokine receptor 6 (CCR6) may be involved in the recruitment of immune cells in allergic diseases, but the role of CCR6 in allergic rhinitis (AR) remains unclear.

  Objective   To detect the expression of CCR6 on Treg surface in peripheral blood of AR patients and the distribution and expression of CCR6 on nasal mucosa of AR mice, and explore the mechanism of CCR6 chemotactic recruitment of immune cells in AR.

  Methods   Peripheral blood samples from allergic rhinitis patients and healthy people were collected, and the proportion of Treg and the expression of CCR6 on its surface were detected by flow cytometry. Then AR mouse model was established, hematoxylin and eosin staining was used to observe eosinophil infiltration in nasal mucosa of AR mice and control mice, and immunohistochemical staining was used to detect the expression of CCR6 protein in nasal mucosa.

  Results  The proportion of CD4 ⁺ CD25 ⁺ FoxP3 ⁺ Treg (2.92 ± 1.83% vs 5.23 ± 2.58%) and CCR6 ⁺ Treg (30.02 ± 11.50% vs 50.20 ± 11.67%) in the AR patients were significantly lower than those in the HC group (P<0.01, respectively), and there was a positive correlation between CD4 ⁺ CD25 ⁺ FoxP3 ⁺ Treg and CCR6 in the peripheral blood of the AR patients (r=0.889, P<0.01). The number of eosinophils 24.0 (14.5, 31.5) vs 0 (0, 1.8) and cells expressing CCR6 (136.25 ± 26.04 vs 81.00 ± 23.08) in the AR group was significantly higher than that in the control group (P<0.01, respectively), and there was a positive correlation between eosinophils and cells expressing CCR6 in the nasal mucosa of AR mice (r=0.766, P<0.01).

  Conclusion  The changes of CCR6 in AR peripheral blood and nasal mucosa suggest that CCR6 is involved in the pathogenesis of AR and may be related to the induction of chemotaxis of immune cells.