SLPI and acute respiratory distress syndrome: In both the ARDS and the control, plasma PI3 and SLPI demonstrated moderate correlations with APACHE III score on ICU admission (ρ = 0.34–0.51, P<0.01 for all analyses), but plasma HNE only showed correlation with APACHE III score in the ARDS samples (ρ = 0.51, P<0.0001).