Background: T-helper cell type 2 lymphocytes (Th2) play an important role in initiation, progression and persistence of asthma. An increase in Th2 cells activity in asthma may be due to a reduction in T-regulatory cells (nTreg) that normally inhibit Th2 cells. Objective: The aim of this study was to reveal the association between T-regulatory cells blood content and cytokines production by Th1 and Th2 cells in patients with asthma. Methods: 81 patients with asthma and 30 matched control subjects were included. All underwent clinical examination and spirometry. Investigation of nTreg in blood was carried out by flow cytometry. nTreg were defined as a fraction of CD4+CD25+-lymphocytes with a high level of CD25 expression (CD4+CD25hi-cells). IFN-γ and IL-4 cytokines concentration in blood was assessed by enzyme immunoassay. Results: Patients with asthma had significantly lower values of CD4+CD25hi-cells than controls (5,38 (2,84-6,59)% vs 7,40 (6,41-8,52)%; p<0,001). Decrease of CD4+CD25hi-cells blood content correlated with increasing clinical symptoms of asthma (r=-0,80; p<0,001) and decreasing FEV1 (r=0,31; p<0,01). Decrease of CD4+CD25hi-cells content also correlated with increased IL-4 production (r=-0,50; p<0,001) and decreased IFN-γ production (r=0,43; p<0,001) and IFN-γ/IL-4 ratio (r=0,64; p<0,001). Whereas increase of IL-4 production correlated with increasing clinical symptoms of asthma (r=0,69; p<0,001) and decreasing FEV1 (r=-0,61; p<0,001). Conclusion: Decrease of T-regulatory cells blood content in asthma is associated with increased functional activity of Th2 cells (increased IL-4 production, decreased IFN-γ/IL-4 ratio) and both these parameters are linked to disease severity.
Antanovich et al. (Sun,) studied this question.