High levels of a blood protein called mannose-binding lectin associated with lower risk of heart attack

High levels of a blood protein called mannose-binding lectin (MBL) are associated with lower risk of heart attack, particularly among diabetics, report Saevardottir and colleagues. They suggest that measuring this protein in the bloodstream may help doctors decide if certain patients should receive additional treatments to decrease their heart attack risk, according to a study in the January 3rd issue of The Journal of Experimental Medicine.

Mannose-binding lectin, or MBL is a human plasma protein with anti-microbial properties. It can coat a wide range of pathogens (viruses, bacteria, fungi, protozoa) and flag them for immune destruction, independently of immune system antibodies. Increased duration, severity and frequency of infections have been observed in patients who are MBL deficient or have an immature or compromised immune system.

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.