Cigarette smoking alters bronchial mucosal immunity in asthma.

Rationale: Cigarette smoking worsens asthma and is associated with reduced response to corticosteroid therapy. As cigarette smoke is known to have immunomodulatory effects, we hypothesized that one mechanism by which smoking mediates its adverse effect is by reduction of the numbers of bronchial mucosal dendritic cells (DCs), which control B-cell growth and T-cell responses.

Objectives: We set out to sample the bronchial mucosa in smoking and never-smoking patients with asthma and to count DCs, B cells, and cells expressing genes for two key T-lymphocyte regulatory cytokines.