Effects of LL-37, hBD-3 and HNP-1 on neutrophil apoptosis. Neutrophils (10⁶ cells/mL) were incubated for 18 h at 37°C in RPMIFBS in the absence (Control) or presence of LL-37 ( μg/mL), hBD-3 (1 μg/mL), HNP-1 (10 μg/mL), or their combination ( μg/mL LL-37 and 1 μg/mL hBD-3, 1 μg/mL hBD-3 and 10 μg/mL HNP-1, 10 μg/mL HNP-1 and 0.1 μg/mL LL-37, or 0.1 μg/mL LL-37, 1 μg/mL hBD-3 and 10 μg/mL HNP-1). Neutrophils were also incubated alone for 18 h at 4°C in the absence of LPS (Resting). After incubation, neutrophil apoptosis was quantitated and expressed as a percentage of apoptotic cells. Data are the mean ± SD of 4 to 5 separate experiments. Values are compared between the absence (Control) and presence of LL-37, hBD-3, HNP-1, or their combination. *, ***.