DP inhibits constitutive apoptosis of normal neutrophils.

<p>(A–C) Neutrophils were isolated from normal peripheral blood (n = 5) and then incubated for 24 h in the absence (Con) and presence of DP (10 µg/ml), DF (10 µg/ml) and GM-CSF (100 ng/ml) (A) or with and without DP (10 µg/ml), Der p 1 (10 µg/ml) and Der p 2 (10 µg/ml) (B). Neutrophils were pre-treated in the absence (Con) and presence of E64 (50 µg/ml) and aprotinin (Ap) (50 µg/ml) for 1 h, after which the cells were incubated for 24 h in the absence (Con) and presence of DP (10 µg/ml)(C). Neutrophils apoptosis was analyzed by measuring the binding of annexin V-FITC and PI. Data are presented relative to the control, which was set at 100% as the means ± SD. **<i>p</i><0.01 indicates a significant difference between the control and DP-treated groups.