Changes and significance of peripheral blood helper T cell 9 and interleukin-9 in patients with chronic obstructive pulmonary disease

Objective: To observe the changes of peripheral blood helper T cell 9 (Th9) and interleukin-9 (IL-9) in the stable and acute exacerbation phases of chronic obstructive pulmonary disease (COPD) so as to investigate its effects and clinical significance in the pathogenesis of COPD. Methods: A total of 42 patients (22 patients in the acute exacerbation chronic obstructive pulmonary disease (AECOPD) and 20 patients in the stable chronic obstructive pulmonary disease (SCOPD) and 15 healthy controls were enrolled in this study to test the Th9 content by flow cytometry (FCM) and the serum IL-9 level by enzyme linked immunosorbent assay (ELISA). Results: The levels of Th9 and IL-9 in Group AECOPD were significantly higher than those in Group SCOPD (0.91±0.17 vs 0.27±0.13 and 0.28±0.13, P<0.05; 3.36±2.59 vs 1.47±0.83 and 1.82±0.62, P<0.05), and the IL-9 level and the Th9 ratio in Group AECOPD showed slight positive correlation (r=0.436, P<0.05). There was no significant difference in the IL-9 level and Th9 ratio in the AECOPD and SCOPD (P>0.05). Conclusions: The Th9 cells may be involved in the pathogenesis of AECOPD by secreting IL-9.