Diverse Production of Interferons α,β,and γ by Airway Leukocytes of Asthmatics with Regard to Cigarette Smoking and Corticosteroid Treatment

The production of interferon-α(IFN-α), IFN-β, and IFN-γ by airway leukocytes from induced sputa (IS) of asthmatics was investigated. The groups consisted of 32 corticosteroid-free asthmatics (A), with 13 nonsmokers (nS) and 19 smokers (S), and 30 inhaled corticosteroid-treated asthmatics (cA) with 14 nS and 16 S. The control healthy group (H) comprised 11 nS and 15 S. The levels of IFNs in media from cultures of IS leukocytes were assessed by ELISA. The cells of the smokers produced lower amounts of IFN-α than those of nonsmokers in groups H, A, and cA (p = 0.0417, 0.0002, 0.0495, respectively) and significantly higher amounts of IFNβ than nonsmokers in groups H (p = 0.0044) and cA (p = 0.0007). No differences in the levels of IFN-γ were observed between S and nS in groups H (p = 0.8148), A (p = 0.8339), and cA (p = 0.0722). In the entire group of smokers, smoking indices correlated negatively with IFN-α (R_S = −0.4374, p = 0.0006), and positively with IFN-β (R_S = 0.4239, p = 0.0009). There was no correlation with IFN-γ (R_S = 0.0471, p = 0.7004). The results suggest that production of IFNs by the airway leukocytes of cA may be modified by cigarette smoking toward deficient production of IFN-α and excess production of IFN-β, which may have implications in the pathophysiology of asthma.