In the co-culture, the addition of dexamethasone in the presence of infection reduced the release of TNF-α and IL-10 by 82 %, from 13359.6 ± 385.7 to 2371.2 ± 594.4 pg/ml and 92 % from 860.3 ± 237.4 to 641.4 ± 116.5 respectively (p < 0.05) without significant change on IL-1β, IL-6 and IL-8 release (Additional file 1: Figure S2, online supplement). This evidence concerns the gene CXCL8 and infection.