OBJECTIVES:
Mannan-binding lectin (MBL) acts as a pattern-recognition molecule directed against oligomannan, which is part of the
cell wall of
yeasts and various
bacteria. We have previously shown an association between MBL deficiency and anti-Saccharomyces
cerevisiae mannan
antibody (ASCA) positivity. This study aims at evaluating whether MBL deficiency is associated with distinct
Crohn's disease (CD)
phenotypes. METHODS: Serum concentrations of MBL and ASCA were measured using
ELISA (
enzyme-linked immunosorbent assay) in 427 patients with CD, 70 with
ulcerative colitis, and 76 healthy controls. CD
phenotypes were grouped according to the Montreal Classification as follows: non-stricturing, non-penetrating (B1, n=182), stricturing (B2, n=113), penetrating (B3, n=67), and perianal disease (p, n=65). MBL was classified as deficient (<100 ng/ml), low (100-500 ng/ml), and normal (500 ng/ml). RESULTS:
Mean MBL was lower in B2 and B3 CD patients (1,503+/-1,358 ng/ml) compared with that in B1
phenotypes (1,909+/-1,392 ng/ml, P=0.013). B2 and B3 patients more frequently had low or deficient MBL and ASCA positivity compared with B1 patients (P=0.004 and P<0.001).
Mean MBL was lower in ASCA-positive CD patients (1,562+/-1,319 ng/ml) compared with that in ASCA-negative CD patients (1,871+/-1,320 ng/ml, P=0.038). In
multivariate logistic regression modeling, low or deficient MBL was associated significantly with B1 (negative association), complicated disease (B2+B3), and ASCA. MBL levels did not
correlate with disease duration. CONCLUSIONS: Low or deficient MBL serum levels are significantly associated with complicated (stricturing and penetrating) CD
phenotypes but are negatively associated with the non-stricturing, non-penetrating group. Furthermore, CD patients with low or deficient MBL are significantly more often ASCA positive, possibly reflecting delayed clearance of oligomannan-containing
microorganisms by the
innate immune system in the absence of MBL.
