New research suggests that the immune system has a big role to play in the onset and progression of the most common form of dementia, Alzheimer’s Disease. The study’s findings could lead to new treatments for dementia, which is thought to affect nearly 44 million people worldwide.

A team at Duke University, who published their findings in The Journal of Neuroscience, discovered while running tests on mice that cells designed to protect the brain from infections will consume the essential amino acid arginine and undergo changes during the early stages of Alzheimer’s, according to Medical News Today. The team found that they could block the arginine consumption.

They used a drug called difluoromethylornithine (DFMO) on the mice to block the enzymes that break down the amino acid. The drug, which is usually used to treat some forms of cancer, helped to improve two major symptoms of the disease: memory loss and the build-up of sticky proteins or brain plaques. The results of the memory tests on the mice also improved, according to International Business Times.

Senior author and professor of neurology at Duke University School of Medicine Dr. Carol Colton explained that the study opened up “new avenues to think about what causes Alzheimer’s Disease” and new methods of treatment. Though this method of treatment produced positive results, Colton said a more suitable agent will have to be found eventually. She said that the results are “favorable” and the team is “cautiously optimistic.”

James Pickett, head of the Alzheimer’s Society, said that the study “joins some of the dots” in understanding what causes the disease. He added that the next step would be to demonstrate that “targeting arginine metabolism in the brain can reduce the death of brain cells,” which was not done in the study.

The role of immune system cells in dementia still remains unclear. However, the study’s results are encouraging in that they establish a true link between Alzheimer’s and the suppression of the immune system.