["Mannose-binding lectin (MBL) is a pattern-recognition molecule and an important component of the innate defense system. Anti-Saccharomyces cerevisiae antibody (ASCA) is a well known serologic marker of Crohn's disease (CD). This study aimed to investigate the association between MBL, ASCA, and clinical features in Korean CD patients.", 'Two hundred and eighty-three well-characterized CD patients were included. MBL concentrations, serum IgG and IgA concentrations of ASCA were determined by ELISA. Low MBL concentrations were defined as serum MBL concentrations <500 ng/ml.', 'Low MBL concentrations were observed in 41 CD patients (14.5%). No differences in MBL concentrations were detected according to the age at diagnosis, behavior, or the location of patients with CD. MBL concentrations and the frequency of low MBL concentrations did not differ according to ASCA positivity. The presence of perianal involvement (p=0.043), younger age at diagnosis (p=0.021), and intestinal surgery (p=0.047) were more frequently associated with ASCA positive patients.'] Is mannose-binding lectin deficiency associated with anti-Saccharomyces cerevisiae antibody in Korean Crohn 's disease patients?