PON1 and infection: In patients stratified by the infection site, the most pronounced decreases in PON1 were observed in abdominal infections (28.2 U (24-33)), significantly lower than in the case of the pulmonary (45 U (38.5-51.5)), blood (44.3 U (34-54.5)), and other site (46.4 U) infections (p = 0.017).