RT Journal Article SR Electronic T1 Dual effect of neutrophils on secretory component production by human bronchial epithelial cells JF European Respiratory Review JO EUROPEAN RESPIRATORY REVIEW FD European Respiratory Society SP 175 OP 176 DO 10.1183/09059180.00010111 VO 15 IS 101 A1 C. Pilette A1 B. Detry A1 A. Guisset A1 Y. Sibille YR 2006 UL http://err.ersjournals.com/content/15/101/175.abstract AB A decreased bronchial expression of secretory component (SC) was demonstrated in severe COPD, and correlated with neutrophils. Mechanisms of epithelial cell/neutrophils interactions remain however poorly understood. Calu-3 (human bronchial epithelial) cells were incubated after confluence (in triplicate conditions) with various ratios of activated neutrophils (0.5:1 to 15:1, neutrophils: Calu-3 cells). After 48hrs of co-culture supernatants were assayed for SC by ELISA. SC production by Calu-3 cells increased at intermediate neutrophil numbers (316±32 versus 193±19ng·ml−1, ratio of 5:1 versus control, mean±SEM of 3 experiments, p = 0.05). In contrast, a trend for decrease in SC was observed with high neutrophil numbers (111±19 versus 193±19ng·ml−1, ratio of 15:1 versus control, p = 0.06). The addition of secretory leukocyte protease inhibitor further increased SC upregulation at intermediate ratios, and inhibited the SC decrease at high neutrophil numbers. The mechanism of SC up-regulation by neutrophils did not implicate TNF-α or IL-1β. This study provides direct evidence of a dual effect of neutrophils on epithelial SC. Our data suggest that neutrophils could differently affect epithelial immune secretory function according to the extent of neutrophil influx and/or to the reactivity of airway epithelial cells.