HMGB1 and chronic obstructive pulmonary disease: Compared to NS and HS (1.62 ± 0.27 and 1.59 ± 0.27 ng/mL, respectively; Fig. 1a), the HMGB1 levels in the induced sputum were significantly higher in patients with asthma, COPD, and ACO (4.51 ± 0.39, 15.77 ± 1.32, and 13.59 ± 1.22 ng/mL, respectively).