Inhibition by roxithromycin of cytokine mRNA expression in SM-exposed SAE cells. Various concentrations of roxithromycin were added to cells exposed to 100 μM SM. Total RNA was isolated from cells 24 h after exposure. Cytokine mRNA was quantified using real-time RT-PCR. Results are expressed as a percentage of the control (unexposed) cells. RXM, roxithromycin. *P < 0.05, **P < 0.01, ***P < 0.001 versus cells exposed to SM only.