IL1B and chronic obstructive pulmonary disease: We identified an asthma-predominant cluster with eosinophilic inflammation and elevated TH2 inflammatory mediators, a COPD-predominant group with elevated proinflammatory cytokines, and an asthma and COPD overlap group that clinically had chronic bronchitis, increased bacterial colonization, elevated sputum IL-1β and TNF-α levels, and a sputum neutrophilia.