The concentration of C3 and C4 reduced with the increase of the severity of AP(C3 [g/L]: Control: 1.16 ± 0.29; MAP: 0.72 ± 0.28; MSAP: 0.61 ± 0.22; SAP: 0.42 ± 0.31; C4 [g/L]: Control: 0.23 ± 0.06; MAP: 0.19 ± 0.07; MSAP: 0.14 ± 0.06; SAP: 0.10 ± 0.08) (Figure 1).A negative correlation between C3 levels and APACHE II scores was observed (C3: r = −.233, P = .004). This evidence concerns the gene C4A and alkaline phosphatase measurement.