Immunophenotype in acute exacerbation of chronic obstructive pulmonary disease: a cross-sectional study

Background: Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, and the immune inflammatory response is thought to play an important role in pathogenesis. However, the immunophenotype of patients with COPD is unknown. Herein, we evaluated the immunophenotype of patients with acute exacerbation of COPD (AECOPD). Methods: A cross-sectional study was conducted in West China Hospital from September 2018 to October 2019. The proportion of CD4+T lymphocyte subtypes (Th1, Th2, Th17 and Treg) and levels of serum cytokines in the peripheral blood of patients with AECOPD, stable COPD (SCOPD), healthy smokers (HSs)and healthy controls (HCs) were evaluated. Results: A total of 15 HCs, 19 HSs, 42 patients with SCOPD, and 55 patients with AECOPD were included. Compared to patients with SCOPD, Th1 cells, Th17 cells, Treg cell ratio, Th1/Th2 cell ratio, and the levels of C-reactive protein, interleukin (IL)-6, and IL-10 were significantly increased in patients with AECOPD (P <0.001), while the proportion of Th2 cells was significantly reduced (P < 0.01). The proportion of Th17 cells was positively correlated with COPD Assessment Test score (r= 0.266, P= 0.009), modified Medical Research Council dyspnea score (r= 0.858, P <0.0001), and Th1 cell ratio (r= 0.403, P <0.0001) and negatively correlated with forced vital capacity (r = - 0.367, P= 0.009) and proportion of Th2 cells (r=- 0.655, P <0.0001). Conclusions: The immunophenotype of patients with AECOPD shows abnormal activation of Th1, Th17, and Treg cells. There is a correlation between the proportion ofTh17 cells and the severity of COPD; therefore, this may represent a novel index for the evaluation of COPD severity.