Effect of tiotropium bromide on expression of CD8+CD25+FoxP3+ regulatory T cells in patients with stable chronic obstructive pulmonary disease

The expression of CD8+CD25+FoxP3+ regulatory T cells (CD8+Tregs) in the peripheral blood of patients with stable chronic obstructive pulmonary disease (COPD), and the effect of muscarinic cholinergic receptor antagonist tiotropium bromide on the expression of CD8+Tregs were investigated. Twenty-three patients with moderate to severe stable COPD were enrolled in this study. All patients inhaled tiotropium bromide (18 μg daily) for 3 months. Before and after inhalation of tiotropium bromide, peripheral blood samples were collected from the patients, and T cells were labeled by three-color labeled monoclonal antibodies. Flow cytometry was used to detect the quantity and percentage of CD8+T cells, CD8+CD25+T cells, CD8+Tregs, CD4+T cells, CD4+CD25+T cells and CD4+CD25+FoxP3+ regulatory T cells (CD4+Tregs) respectively. The percentage of CD4+T cells was increased from (27.82±2.18)% to (35.53±1.3)% (t=3.20, P=0.004) in the peripheral blood of patients with stable COPD after inhalation of tiotropium bromide for 3 months, that of CD4+CD25+T cells was decreased from (10.03 ±1.42)% to (4.21 ±0.65)% (t=3.78, P=0.001), and that of CD8+Tregs was increased from (8.41 ±1.68)% to (21.34 ±4.20)% (t=2.72, P=0.013). At baseline, CD8+T cells, CD8+CD25+T cells and CD4+Tregs were detectable in the peripheral blood, but no significant changes were observed after treatment. Linear correlation analysis revealed that the difference before and after treatment in CD4+T cells and CD4+CD25+T cells was negatively correlated with the ratio of change in CD8+Tregs before and after treatment (r=−0.61, P=0.013; r=-0.72, P=0.001 respectively). In the peripheral blood of patients with stable COPD, there was the expression of CD8+Tregs and CD4+Tregs. Muscarinic receptor antagonist, tiotropium bromide, can promote the amplification of CD4+T cells, inhibit the expression of CD25+T cells, and enhance the expression of CD8+Tregs. CD8+Tregs and CD4+Tregs can be used as new indicators to understand the immune status of patients. They are helpful in judging the treatment efficacy and disease immunophenotype.