IL4 and chronic obstructive pulmonary disease: COPD-BS patients had more IOS indicators of SAD compared with COPD-TS, suggesting the presence of eosinophilic inflammation associated with SAD.5,10,11,21 These findings indirectly show the predominance of the Th2 response activation by CD4+ Th2 lymphocytes and airway resistance, as described in the pathophysiology of COPD-BS.10,12 In two similar studies involving women, higher levels of some inflammatory cytokines reported here were observed in COPD-BS compared with COPD-TS, specifically IL-1ra, IL-4, IL-6, IL-8, periostin, and eotaxin.