Background: The urokinase-type plasminogen activation (uPA) system and the mannan-binding
lectin (MBL) complement activation pathway are involved in regulation of immune responses.
The blood concentrations of these molecules in the individual patient thus could be
related to the risk of postoperative infectious complications. The aim of this retrospective
study was to determine the association between the soluble uPA receptor (suPAR) and MBL
concentrations and the development of postoperative bacterial infectious complications.
Methods: Blood samples were drawn preoperatively from 544 patients scheduled to undergo
primary resection for colorectal cancer. Plasma suPAR was determined by enzyme-linked immunosorbent
assay and serum MBL by time-resolved immunofluorescent assay. The following
infectious events were recorded during the first month after surgery: surgical site or perineal
infection or both, intra-abdominal abscess, anastomotic leakage, pneumonia, and blood
stream infection. Data on perioperative blood transfusions in addition to clinical baseline
characteristics were included as well.
Results: The numbers of surgical site infections, intra-abdominal abscesses, anastomotic
leakages, pneumonias, and blood stream infections were 51, 20, 32, 78, and 19, respectively.
Univariate analysis showed that elevated concentrations of suPAR (p = 0.01; odds ratio [OR]
2.2; 95% confidence interval [CI] 1.2, 3.9), low concentrations of MBL (p = 0.047; OR 0.9; 95%
CI 0.8, 1.0), and perioperative blood transfusion (p = 0.006; OR 1.5; 95% CI 1.1, 2.0) were associated
with the development of pneumonia. Significant associations with other bacterial
infections could not be demonstrated. Multivariate analysis including disease stage, sex, and
age showed that suPAR, MBL, and perioperative blood transfusion were significantly and independently
associated with postoperative pneumonia.
Conclusion: Concentrations of suPAR and MBL, in addition to perioperative blood transfusion,
were significantly associated with the development of postoperative pneumonia. No
other statistically significant relationships could be demonstrated. Thus, further research
should be directed to clarifying the biological role of these two molecules in the development
of postoperative pneumonia.
