( Study suggests chronic infections may c...)Immune system has evolved to prevent autoimmune disease

New research finds the human immune system has foregone evolutionary changes that would allow it to produce better antibodies in less time because the improved antibodies would be far more likely to attack the body's own tissues. The Rice University study finds the immune system has evolved a near-perfect balance for producing antibodies that are both effective against pathogens and unlikely to cause autoimmune disease.

The findings will be published in the journal Physical Review Letters. They are based on a new model of the immune system that is the first to simulate the hierarchical nature of the body's immune response. The model predicts that chronic infections may lead to autoimmune diseases, a scenario that has been proposed as a cause of some rheumatic diseases like arthritis.

"There are as many as a 100 million unique antibodies circulating through our bodies at any given time, but just three or four of these might be effective against any particular disease," said Michael Deem, the John W. Cox Professor in Biochemical and Genetic Engineering and professor of physics and astronomy. "When we get sick, the immune system identifies the particular antibodies that are effective, as it rapidly creates and mass produces mutant white blood cells called B cells that make only these antibodies."

Deem said prior research has identified a number of alternate strategies the immune system could use to reduce the time needed to create an effective B cell. In addition, these methods also could produce antibodies that are more apt to bind with disease cells. The upshot would be an immune system that responds faster and more effectively against disease."This should help us get well faster, so the question becomes, 'Why didn't we evolve that kind of adaptive response?'" Deem said.

Deem's analysis falls within a branch of physics called statistical mechanics, which uses a sys
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Source:Rice University