BACKGROUND: It can be difficult to distinguish between bronchial asthma and chronic obstructive pulmonary disease (COPD) clinically, although these conditions are associated with different profiles of inflammatory cytokines and immune cells. This study aimed to compare T-lymphocyte subsets and inflammatory cytokines in the serum and sputum of patients with bronchial asthma and COPD who had respiratory function testing.

MATERIAL AND METHODS: The study included 42 patients with bronchial asthma, 48 patients with COPD, and 45 patients with bronchial asthma complicated with COPD. The percentage predicted values of the forced expiratory volume in one second (FEV1), the forced vital capacity (FVC), and the peak expiratory flow (PEF) rate were measured. Serum and sputum levels of interleukin (IL)-4, IL-5, IL-9, IL-13, IL-1β, IL-6 and tumor necrosis factor-α (TNF-α) were measured using an enzyme-linked immunosorbent assay (ELISA). Flow cytometry measured the CD4 and CD8 T-lymphocyte subsets, and the CD4: CD8 ratio was calculated.

RESULTS: The FEV1, FVC, and PEF were significantly lower in patients with COPD compared with the other two patient groups. Serum and sputum levels of IL-4, IL-5, IL-9 and IL-13 were significantly increased in the COPD patient group, and levels of TNF-α, IL-1β and IL-6 were significantly increased in the bronchial asthma patient group. The CD4: CD8 ratio in sputum was lowest in bronchial asthma patient group and highest in COPD patient group.

CONCLUSIONS: The detection of serum and sputum inflammatory cytokines and T-lymphocyte subsets may distinguish between bronchial asthma and COPD.

Keywords: Bronchial Diseases, Immunity, Cellular, Lung Diseases, Asthma, Cytokines, Forced Expiratory Volume, Interleukins, Pulmonary Disease, Chronic Obstructive, Respiratory Function Tests, Sputum, T-Lymphocyte Subsets, Vital Capacity