Quantitation of neutrophil degranulation and myeloperoxidase (MPO) release after bacteria (hkBa, A) or PGN (B) stimulation in the presence of compstatin, a C3 convertase inhibitor, or the immunodepletion of complement factors. Data are shown as mean ± SD of 10 independent donors and depict MPO activity in supernatants collected from stimulated neutrophils (left panels), changes in released MPO after the normalization to bacteria or PGN stimulation in the presence of autologous serum (AHS), which was considered 100% (right panels). Unless otherwise marked, statistically significant differences compared to bacteria and/or PGN stimulation in the presence of AHS (shaded) are depicted graphically (* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001), and were computed by repeated measures one-way ANOVA with Holm–Sidak’s multiple comparisons test (left panels) or one sample t test compared to the normalized value (right panel).