CASP9 and polyarteritis nodosa: Our results demonstrated that PAN damage (30 μg/ml; 48 h) significantly increased the activity of Caspase-8 (p < 0.01; PAN vs. Controls), Caspase-9 (p < 0.001; PAN vs. Controls) and Caspase-3 (p < 0.05; PAN vs. Controls) (Table 3, Fig. 4, Supplementary Fig. 2).