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Low Levels Of Natural Antibody Linked To Stroke Risk

New research from Sweden reveals that a person’s chance of having a stroke is linked to low levels of a natural antibody in the immune system: the researchers hope to develop a vaccine that stimulates the immune system to boost levels of the antibody and thus increase the body’s own defenses against arteriosclerosis and stroke.

The finding is the result of a study led by Professor Johan Frostegård at the Karolinska Institutet in Stockholm, Sweden, and you can read a report about it online in the 11 February issue of Stroke, a journal of the American Heart Association.

Arteriosclerosis is when plaque accumulate on the walls of blood vessels. It eventually bursts, causing a blood clot (thrombosis). It is a common cause of stroke (where a clot blocks blood flow in the brain), and myocardial infarctions or heart attacks.

Frostegård and colleagues had previously shown that high levels of a natural immunoglobulin M antibody known as anti-PC (anti-phosphorylcholine) are linked to slower progression of arteriosclerosis, and that low levels of anti-PC are associated with higher risk for cardiovascular disease.

For this study they concentrated on the link between anti-PC and stroke. They compared 227 first-time stroke patients (125 men and 102 women) with 445 controls matched by age and gender.

The subjects were part of population-based cohorts recruited between 1985 and 1999 to take part in the Västerbotten Intervention Project (VIP) and the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) project in Northern Sweden.

After taking into account other risk factors such as age, gender, smoking status, cholesterol, diabetes, blood pressure and BMI (body mass index, a measure of obesity), they found that:

  • Low levels (under 30 per cent) of PC antibodies were significantly linked to a higher risk of having a stroke (multivariately adjusted odds ratio was 1.62 with confidence interval CI ranging from 1.11 to 2.35).
  • This risk was 3 times higher for women.

The researchers concluded that:

“Low anti-PC is a novel independent risk marker for development of stroke.”

“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,” they added.

Frostegård told the press that they were already pursuing the possibility of a vaccine or some other way of stimulating the immune system to produce anti-PC antibodies:

“We are now examining the possibility of developing new immunological treatments for arteriosclerosis and stroke, either in the form of a vaccine to stimulate the immune defense or immunization through the injection of antibodies.”