Previous studies have implicated natural immunoglobulin M antibodies specific for phosphorylcholine (anti-PC) in atherosclerosis, with low levels of anti-PC associated with higher risk for cardiovascular disease. Johan Frostegard, from Karolinska Institutet, and colleagues explored the association between anti-PC and the incidence of stroke.  Comparing 227 individuals who had suffered stroke over a 13-year period with 445 sex and age-matched controls, and controlling for confounding factors, the team discovered that levels of PC antibodies below 30% correlated with a higher risk of stroke. In women, that increased risk corresponded to a three-fold increase.  Writing that: “Low anti-PC is a novel independent risk marker for development of stroke,” the researchers urge that: “Measurements of anti-PC could be used to identify immunodeficient subjects at an increased risk for stroke. The possibility that such subjects might be targets for novel modes of treatment such as immunotherapies deserves further investigation.”