Background: Deficiency of the mannan‐binding lectin (MBL) pathway of innate immunity leads to increased susceptibility to infections. In patients with colorectal cancer, postoperative infection is associated with poor prognosis. The aim of the present study was to evaluate (1) the relation between the MBL pathway and postoperative infectious complications and survival of patients resected for colorectal cancer and (2) the role of MBL as acute phase reactant compared to CRP. Methods: Preoperative MBL concentration, MBL/MBL‐associated serine protease (MASP) activity and CRP were determined in serum from 611 patients and 150 healthy controls. The patients were observed for 8 years. Postoperative infections, recurrence and survival were recorded. Results: The MBL pathway components were increased in the patients (P < 0.0001) compared to healthy controls. Low MBL levels were predictive of pneumonia (P = 0.01), and pneumonia (n = 87) was associated with poor survival (P = 0.003, HR = 1.5, 95% CI 1.1–1.9). MBL and MBL/MASP activity could not predict postoperative overall infections. MBL showed no correlation (spearman's ρ = 0.02, 95% CI −0.06–0.10) with CRP. Conclusions: Low preoperative MBL levels are predictive of pneumonia, which is associated with poorer survival. MBL concentration and MBL/MASP activity was not predictive of other postoperative infections or long‐term prognosis. MBL apparently is not a surrogate measure of CRP.
Preoperative Mannan‐Binding Lectin Pathway and Prognosis in Colorectal Cancer