Higher Frequencies of CD161+ Circulating T Lymphocytes in Allergic Rhinitis Patients Compared to Healthy Donors

Abstract

Background:Th17 is a subset of T-helper lymphocytes that produce proinflammatory cytokines, mainly IL-17. Serum IL-17 is increased in allergic patients and relates to clinical severity. Recently, it has been reported that CD161 is a highly upregulated gene in Th17 clones and all IL-17-producing cells are contained in CD161⁺ T cells. This study aimed at comparing the frequency of peripheral CD161⁺ T cells in patients with allergic rhinitis (AR) and in healthy controls and at relating CD161 expression with symptom severity. Methods: Forty-four patients with AR and 29 healthy non-allergic subjects were evaluated. CD161 expression was evaluated on CD3⁺, CD4⁺ and CD8⁺ cells by double immunofluorescence staining and fluorescence activated cell sorter analysis. Symptom severity was assessed by the Visual Analogue Scale. Results: Allergic patients showed a significantly higher frequency of CD3⁺CD161⁺, CD4⁺CD161⁺ and CD8⁺CD161⁺ cells than healthy non-allergic subjects (p < 0.0001). Moreover, the expression of CD161 cells was significantly related to clinical severity. Conclusions: This study provides evidence that a higher frequency of CD161⁺ T cells is present in the peripheral blood of AR patients.