IL2 and chronic obstructive pulmonary disease: Despite increased IL-2 and TGF-β (also considered to be a type of anti-inflammatory chemokine that promotes Tregs expression) in patients with COPD and elevated Tregs frequencies in AECOPD (Jin et al., 2014), higher levels of pro-inflammatory molecule such as IL-1β, IL-6, and IL-23 were predominant in patients with COPD.