Expression of Th1, Th2 and Th17 cytokines in CD4+ T cells in peripheral blood of asthma patients

Background: The asthmatic inflammation is mainly orchestrated by T cells producing Th1 and Th2 cytokines. Aim: To characterize the inflammatory features of peripheral blood T cells of asthma patients. Methods: T cells were isolated from peripheral blood of 93 asthma patients [median age 48±14 years, 59 female, FEV 1 (median) 88±20% of predicted]. In 23 patients (25%) asthma was controlled, in 32 (34%) partly controlled and in 38 (41%) uncontrolled. 14 patients were treated with oral steroids. The frequency of cytokine producing CD4+ T cells after non-specific stimulation was quantified by flow cytometry. Results: In the whole cohort 7.2±6.6 % of T cells produced IFN-γ, 1.04±0.8% IL-4, 0.21±0.18% IL-5, 0.25±2.8% IL-13, and 0.75±0.43% Il-17. In patients with controlled disease the frequency of IL-4, IL-13, and Il-17 producing CD + T-cells was significantly higher compared with patients with uncontrolled asthma (p=0.03). The same was true when patients treated with oral steroids were excluded from the analysis (p=0.02). Patients with controlled disease on GINA step 1 treatment had a higher frequency of IL-10 producing CD4 + T-cells (p=0.04) compared with patients with uncontrolled asthma. Conclusion: Different degrees of asthma control and GINA treatment steps are reflected by different frequencies of cytokine-producing CD4 + T cells in peripheral blood of asthma patients.