Distribution of γδ and other T-lymphocyte subsets in patients with chronic obstructive pulmonary disease and asthma

Abstract

The role of T lymphocytes in pathogenesis of chronic inflammatory airway diseases - asthma and chronic obstructive pulmonary disease (COPD) has been emphasized in recent years: the importance of αβ T-cells (CD8+ and CD4+) has been widely described. A substantial fraction of γδ T-cells is a composite part of pulmonary T lymphocytes. Specific localisation of γδ T-cells in epithelium/mucosa-rich tissues implies their potential role in local inflammatory immune response, which occurs in chronic inflammatory airway diseases. An investigation was made of the T-lymphocyte subsets in induced sputum (IS), in bronchoalveolar lavage (BAL) and in peripheral blood from 20 patients with COPD (stages II-III; GOLD), 18 patients with asthma (persistent mild to moderate; GINA) and 14 healthy subjects. Relationship of γδ T-cells with lung function and smoking history was analysed. COPD patients had significantly higher numbers of CD8+T-cells in the airways of smokers compared to ex-smokers in the COPD group. A significant positive correlation was found between CD8+T-cells and pack-years of smoking. Differently, the COPD patients had significantly lower relative and absolute numbers of γδ T-cells in IS and in BAL compared to those from asthma or healthy subjects. The quantity of γδ T-cells negatively correlated with forced expiratory volume in 1 s and smoking (pack-years) only in COPD group. Our findings indicate a different local inflammatory response in COPD patients and in asthmatic groups. The reduced amount of γδ T-cells in IS and in BAL from COPD patients raises the hypothesis about their important role in pathogenesis of COPD.