Influence of clarithromycin (A) and M-4 (B) on NF-κB activation in NPFs after LPS stimulation. NPFs at a concentration of 5 × 105 cells/ml were stimulated 1.0 μg/ml LPS in the presence of various concentrations of clarithromycin (CAM) and M-4. After 4 hours, nuclear extracts were obtained from NPFs and NF-κB p50 activity was assayed by ELISA. Data are the mean ± SE of five different subjects. NF-κB, nuclear factor-κB; NPFs, nasal polyp fibroblasts; LPS, lipopolysaccharide; CAM, clarithromycin; ELISA, enzyme-linked immunosorbent assay.