Shyam et al. [143] examined the levels of the proinflammatory cytokines IL-1β and TNF-α and the potential correlation with the severity of airflow limitation in 40 patients with COPD associated with cigarette smoke (CS-COPD) and 40 biomass-smoke exposure (BS-COPD) compared to 80 healthy controls. This evidence concerns the gene IL1B and chronic obstructive pulmonary disease.