Background: Low plasma concentrations and genetic polymorphisms of mannan-binding
lectin (MBL) have been associated with infectious disease complications during various conditions.
The present study examined the nature and expression of MBL deficiency during a
surgery-induced acute-phase response.
Methods: Blood was sampled from 20 consecutive patients before and 1, 3, 5, 7, and 10 days
and 6 weeks after a uniform abdominal operation (transhiatal esophagectomy). Plasma concentrations
of MBL, C-reactive protein (CRP), and secretory phospholipase A2 (sPLA2) were
measured. Patients were classified as low- or high-level MBL producers by their preoperative
concentration (<0.5 or ≥0.5 micrograms/mL), and were cross-verified for actual MBL deficiency
by nucleotide sequencing of both the MBL promoter and exon-1 alleles.
Results: Baseline plasma MBL concentrations correlated with maximal postoperative plasma
concentrations (r = 0.88; p < 0.0001). This was not found for CRP and sPLA2 (r = 0.19 and r =
0.08, respectively). Alleles responsible for structural MBL variants were detected in 40% of
patients and were associated with significantly reduced MBL concentrations (p = 0.005). The
baseline cut-off value in plasma of 0.5 micrograms/mL clearly identified individuals with
variant exon-1 alleles (sensitivity 100%, specificity 83%).
Conclusions: Baseline MBL plasma concentrations are predictive of MBL expression during
the acute-phase response. A baseline cut-off value of 0.5 micrograms/mL can be used to
identify patients with variants in the exon-1 region of the MBL gene without the need for nucleotide
sequencing. Clinical studies may use this easy and quick method to identify MBLdeficient
patients preoperatively, as they are conditionally at risk for infectious complications.
