New research led by TGen in Phoenix and published in the journal Nature Aging describes early biological signs of Parkinson's disease.

That knowledge could one day help scientists improve early diagnosis and treatment.

"If we can understand more what's happening in the body in the early stages of disease, or even before the disease starts, then we can partner with other groups and can use these data to develop more therapies for Parkinson's disease as well," said co-author Elizabeth Hutchins, a computational scientist at TGen.

The study utilized and contributed to a large data trove: the Parkinson Progression Markers Initiative, a large observational study established in 2010 and sponsored by the Michael J. Fox Foundation for Parkinson's Research as well as various industry, non-profit and private partners. 

"Our main goal was to create this resource of the longitudinal study and make that available for the scientific community. And, while we were doing that, we found this interesting finding that we think other people should look into," said Hutchins.

When researchers sequenced RNA in almost 4,900 samples collected from nearly 1,600 people over three years, they found more than 2,000 changes in gene expression.

They also saw alterations in white blood cell counts – more neutrophils, fewer lymphocytes – that show up well before the disease manifests and could hint at inflammation.

"There's changes that are starting to happen in the body. And I think that neuroinflammation is a signal of some of those changes that are already happening," said Hutchins.

But she clarified that those neutrophil and lymphocyte levels are still within normal, healthy ranges, so nothing would jump out at a doctor who requested a complete blood cell count.

"But what we're seeing is that it's significantly more in people with Parkinson's disease than in people that don't have Parkinson's disease. So while it's within that healthy range, it is already increasing," she said.

Experts predict Parkinson's disease will affect 12 million people worldwide by 2040.