Utah scientist says immune system may be key to treating mental illness

From KSL-TV in Utah:

SALT LAKE CITY, Utah -- It is heartbreaking to see someone you love suffer from mental illness. Now a famous Utah scientist says he's made a big breakthrough in the research to find a cure.

Doctors have traditionally treated mental illness with drugs to alter the brain's chemistry, but the University of Utah's Nobel Prize-winning geneticist Dr. Mario Capecchi tried a new approach on a lab mouse. He treated the animal for the illness the same way you would many other illnesses -- by treating its immune system.

Microglia are immune system cells that originate in bone marrow and migrate from blood to the brain acting as the first and main form of active immune defense in the central nervous system (CNS) defending the brain and spinal cord, constantly excavating the CNS and attacking and engulfing infectious agents. Capecchi says compulsive behavior doesn't just affect people. In fact, he had a lab mouse who was suffering from the condition trichotillomania, where one pulls their own hair out. Scientists say it was the mouse that led to the ground-breaking discovery as they found a way to cure him.

"There's a direct correlation, in essence, between the immune system and behavior," Capecchi says.

He says scientists have known for years that there is a connection between behavior and the immune system, but they didn't quite understand it. Now he and his team have discovered it all has to do with a tiny cell called microglia.

Microglia were believed to be "scavenger cells" that would clean up damage in the brain, but Capecchi says the cells are much more powerful than they were letting on.

"What we're saying is microglia are much more sophisticated and are actually controlling behavior, and they have to do it by interacting the nerve cells in your brain," Capecchi says.

They found people and animals afflicted with behavior disorders have deformed microglia cells. So, instead of treating mental illness the way doctors traditionally have -- with medication to alter brain chemistry -- they tried a new approach by treating the immune system.

The researchers used a procedure on the mouse that's commonly practiced on cancer patients -- a bone marrow transplant.

"That cured the disease permanently," Capecchi says. "All the hair grew back, all the lesions were healed, and the mouse no longer removes the body hair."

Capecchi says this new discovery could lead to cures for mental disorders from autism to schizophrenia.

"The book is just opened, and so there are many, many possibilities; and hopefully not only will we pursue it, but also hopefully it will interest other researchers, other investigators, to pursue similar experiments," Capecchi says.