By Robert Sanders, Public Affairs

Marian Diamond

15 NOVEMBER 00 | Next time you feel a little under the weather, try a novel way to boost your immune system - play contract bridge.

In a presentation at last week's meeting of the Society for Neuroscience, biologist Marian Diamond described an experiment showing that contract bridge players have increased numbers of immune cells after a game of bridge.

Based on her previous work, and that of others, Diamond interprets the findings as strong evidence that an area of the brain involved in playing bridge stimulates the immune system, in particular the thymus gland that produces white blood cells called T cells, or T lymphocytes.

If her study is borne out, this would be the first time a specific area of the cortex - in this case, part of the frontal lobe of the brain - has been linked with the immune system.

"People are aware that voluntary activities like positive thinking and prayer work to keep us healthy, but no one has had a mechanism," said Diamond, a professor of integrative biology in the College of Letters & Science. "These data, though preliminary, show that brain activity affects the immune system, and support the possibility of us learning to voluntarily control the level of white blood cells to help combat disease and other illnesses."

The experiment is the culmination of more than 15 years of work on rat and mouse brains by Diamond and her colleagues in search of a cortical-area connected to the immune system. It's also a poignant tribute to her sister, who died when Diamond was 19 of the autoimmune disease systemic lupus erythematosus.

"Someday, I thought, I will find something that correlates with what killed her," said Diamond, 73. "But I'm a neuroscientist, not an immunologist, so I had to touch the immune system through the brain."

Diamond chose to study bridge players from an Orinda women's bridge club because bridge is a game likely to stimulate an area of the brain - the dorsolateral cortex - that she suspected influences the immune system. She selected women as subjects because most of her laboratory experiments have involved immune-compromised female mice.

Diamond and graduate student Jean Weidner divided the 12 women, all in their 70s and 80s, into three groups, and had each group play a one-and-a-half hour bridge set. Weidner, a former phlebotomist, drew blood samples before and after the sets, and delivered them to immunology research associates Peter Schow and Stan Grell to measure the numbers of immune cells.

Only the levels of CD-4 positive T cells changed in the 12 subjects. In two of the groups, levels increased significantly. In the third group, T cell levels increased only slightly, not enough to be statistically significant.

T cells are white blood cells produced by the thymus gland and sent out to patrol the body in search of viruses and other invaders.

Because the brain's cortex is under voluntary control, Diamond hopes her findings lead to ways to educate the brain to improve health.

"If we could find out how to regulate our immune system voluntarily through the brain's cortex, I would feel extremely happy," Diamond said.