Effect of neutrophil elastase inhibitor for in vitro cytokines production. In vitro cytokine production from spleen cells obtained 6 h after secondary challenge. The levels of (a) IL-4, (b) IL-5, (c) IL-13 and (d) IFN-γ in culture supernatant of spleen cells from mice after OVA sensitization and challenge were measured. The results for each group are expressed as the mean ± SD. (n = 12 in each group). *P < 0.05 without re-stimulation with OVA groups (medium) vs. with re-stimulation with OVA groups. #Significant differences (P < 0.05) between OVA/OVA/vehicle/OVA and OVA/OVA/Sivelestat/OVA.