"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."
"Partial overlap of anti-mycobacterial, and anti-Saccharomyces cerevisiae mannan antibodies in Crohn’s disease" In World J Gastroenterology (2008)
"Abstract CONCLUSION: Similar to ASCA, seroreactivity against mycobacteria may define CD patients with complicated disease and a predisposition for immune responses against ubiquitous antigens. While in some patients anti-mycobacterial antibodies strongly cross-react with yeast mannan; these cross-reactive antibodies only represent a minor fraction of total ASCA. Thus, mycobacterial infection unlikely plays a role in ASCA induction."
"Full article: In conclusion, we were able to demonstrate that ASCA-positive patients had significantly more immune reactivities to mycobacterial antigens. In a subgroup of ASCA-positive CD patients, anti-mycobacterial immunoglobulins at least partially represent cross-reactive ASCA, while in others there seem to be separate ASCA and anti-mycobacterial antibodies that do not cross-react. Furthermore, purified anti-M smegmatis IgG showed low or no binding to yeast mannan. Therefore, we postulate that our results reflect more the predisposition of CD patients to develop increased immune reactivities to various ubiquitous antigens in general and mannosylated antigens in particular, rather than a role of mycobacteria in the induction of ASCA."
"Conclusions: These results suggest that systemic MBL helps to prevent excessive inflammation upon access of normally mild pathogens across the damaged intestinal epithelium. Lack of this innate defence promotes antibody responses with cross-reactive potential against common mannan epitopes. These interpretations are compatible with the increased prevalence of ASCA and complicated disease phenotypes in MBL-deficient patients with CD."
"Deficiency for mannan-binding lectin is associated with antibodies to Saccharomyces cerevisiae in patients with Crohn’s disease and their relatives" in Gut (2007)
"Therefore, our paper provides further evidence that genetically altered MBL levels in patients with Crohn’s disease and their relatives could be, at least partly, responsible for the enhanced immune reactivity to yeast antigens seen in a subgroup of these patients and their relatives. However, other factors also contribute to the development of this unusual immune reaction, as there are MBL-deficient healthy people who are ASCA negative."
c.f. "Mannan binding lectin (MBL) gene polymorphisms are not associated with anti-Saccharomyces cerevisiae (ASCA) in patients with Crohn’s disease" in Gut (2006)
"We found no association between the presence of ASCA and polymorphisms/mutations in the MBL gene in a large cohort of CD patients and conclude that the occurrence of ASCA is not related to MBL polymorphisms/mutations. This is in contrast with a previous report in which such an association was suggested. Therefore, we consider the relationship between ASCA and MBL highly controversial."
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