MBL is a protein that circulates in the blood and binds to invading microbes and prepares them for destruction by immune cells. The level of MBL protein in an individual's circulation is genetically determined and can vary drastically from person to person. Several mutations in the gene that codes for MBL result in lower than average concentrations of circulating MBL.
The authors suggest that MBL may protect against heart attack by binding to and helping clear the oxidized forms of cholesterol that build up in arteries. This type of cholesterol is abundant in diabetic patients, which may explain why high levels of MBL are particularly good news for these individuals.
Journal of Experimental Medicine