Altered Expressions of Helper T Cell (Th)1, Th2, and Th17 Cytokines in CD8⁺ and γδ T Cells in Patients with Allergic Asthma

Abstract

Background. T cells play an important role in orchestrating allergic asthma by producing various cytokines; however, little information is available on the phenotype of cytokine-producing T cells, especially CD8⁺ T and γδ T cells in humans. Objective. The aim of this study was to investigate the role of cytokine expressions from circulating CD4⁺, CD8⁺, and γδ T cells in patients with allergic asthma. Methods. Peripheral blood mononuclear cells were isolated from patients with allergic asthma (n = 29) and healthy controls (n = 12). The percentage of helper T cell (Th)1-, Th2-, and Th17-type cytokines interferon-γ (IFN-γ), interleukin (IL)-4, and IL-17, respectively, of CD4⁺, CD8⁺, and γδ T cells was analyzed by flow cytometry. Results. The percentages of IL-4⁺ and IL-17⁺ CD4⁺ T cells increased, whereas IFN-γ⁺ CD4⁺ T cells decreased in patients with allergic asthma compared with healthy controls. The frequency of IL-17⁺ CD4⁺ T cells tended to increase with the severity of allergic asthma. Higher frequency of IL-4-producing and lower frequency of IFN-γ-producing CD8⁺ and γδ T cells were found in patients with allergic asthma compared with healthy controls. The IFN-γ⁺/IL-17⁺ ratio among CD4⁺, CD8⁺, and γδ T cells was significantly decreased in patients with allergic asthma compared with healthy controls. Conclusion. CD8⁺ and γδ T cells might be involved in the pathogenesis of allergic asthma through the release of Th1-, Th2-, and Th17-type cytokines.

• allergic asthma
• CD8⁺
• Th17
• γδ T

Acknowledgments

We express our gratitude to the Renmin and Zhongnan Hospitals for the collection of patients with allergic asthma. We also thank the staff at the Center for Medical Research, Hubei Key Laboratory of Allergy and Immune-Related Diseases of Wuhan University.

Declaration of Interest

The authors report no conflicts of interests. The authors alone are responsible for the content and writing of this paper. And this paper received no funding from outside agencies, organizations, or companies. We confirm that the manuscript has been submitted solely to this journal and is not published, in press, or submitted elsewhere and that all the research meets the ethical guidelines, including adherence to the legal requirements of the study country.