Huntington's trigger found, could help with treatment

New research appears to show that Huntington's disease is associated with an overactive immune response that occurs in the bloodstream and in the brain.

The finding could help researchers identify biological markers that can help monitor how the fatal neurodegenerative disease progresses.

Scientists from Canada, Sweden, the U.S. and England found that patients with Huntington's had increased numbers of immune-system signaling molecules called cytokines in brain tissue.

They then performed tests on mice to see how immune cells of the nervous system responded when triggered by an immune response. They found that in mice with Huntington's, these cells, called microglia, produced much higher levels of cytokines than in mice without the disease.

Researchers believe that a protein called huntingtin that is produced as a result of the disease's genetic mutation causes the immune cells to overreact, which in turn damages neurons in the brains of those with Huntington's.

The discovery may help researchers more effectively identify the stage of the disease, intervene therapeutically before a lot of brain tissue is affected and potentially pave the way for new approaches that target inflammation, say the authors of the study.

"While damage from Huntington's is typically seen in the brain, this new pathway is quite easy to detect in the blood of patients, so we may have found a unique window from the blood into what the disease is doing in the brain," said Thomas Moeller, research associate professor of neurology at the University of Washington.

The study is published in the July 14 online issue of the Journal of Experimental Medicine.

About one in every 10,000 Canadians has Huntington's, according to the Huntington Society of Canada. Symptoms include emotional problems such as depression, cognitive decline and physical deterioration such as weight loss, involuntary movements and the inability to walk, talk and swallow.