Blood cells in people with CFS seem as listless as it can make people feel Mario Mitsis/Alamy

Thirteen years ago, Cara Tomas was rendered bedbound with chronic fatigue syndrome. It came on suddenly, she says, without warning signs. Even now she has good days and bad days due to the lingering effects of the disease. “A lot of people dismiss it as a psychological disease, which is a big frustration,” she says.

Tomas knows more about CFS than most. A PhD student at Newcastle University in the UK, she has just published a paper demonstrating that white blood cells in …