The Use of Multi-Color Flow Cytometry for Identification Offunctional Markers of Ntregs in Patients with Severe Asthma

Introduction: At present, severe asthma is a particular clinical problem. An important role is attributed to dysfunction of nTreg subpopulations of lymphocytes in the pathogenesis of asthma. Therefore, the purpose of this study was to identify markers of nTreg cell function in patients with severe and mild to moderate asthma. Material and methods: The study included sixty patients with asthma (30 with severe and 30 with mild to moderate asthma). The control group comprised 30 healthy volunteers. The diagnosis of asthma was confirmed accordance with generally accepted recommendations (GINA 2008). nTreg immunophenotype CD4/CD25/CD127/FoxP3/GITR/CD152/CCR5/CCR7 was evaluated by multicolor flow cytometry. Results: We showed a significant reduction in the percentage of nTreg (76%) cells and the expression of CD152 (46.2%) in patients with severe asthma compared with mild-moderate asthma (85.5% and 86.7%; p < 0.05). It was observed that the transcription factor FoxP3 expression in nTreg cells positively correlated with FEV1 in patients with severe asthma (r = 0.53; p < 0.05). It was also found that the ratio nTregCCR5⁺/TeffCCR5⁺ was significantly reduced in patients with severe asthma (0.91) compared with mild-moderate (1.58) asthma and control groups (1.55; p < 0.001). Conclusions: There are phenotypic differences in nTreg lymphocytes between patients with severe and mild-moderate asthma. This fact may confirm nTreg cell dysfunction and indicate that the potential markers (FoxP3, CD152, CCR5), can be used to monitor the effectiveness of treatment of bronchial asthma, especially severe disease.