EXPERT REACTION: Potential blood test for chronic fatigue syndrome

Media Release

Potential biomarker for chronic fatigue syndrome

A study suggests a potential diagnostic biomarker for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). More than 2 million Americans are afflicted by ME/CFS, a debilitating condition of uncertain etiology thought to be triggered by infectious agents, among other putative factors. However, a diagnostic biomarker continues to elude researchers. Based on the hypothesis that exposing blood cells to salt-induced osmotic stress forces the cells to devour ATP, a cellular energy metabolite thought to be deficient in ME/CFS patients, Rahim Esfandyarpour, Ronald Davis, and colleagues developed a blood-based assay for CFS. The assay, performed using a high-throughput nanoelectronic needle array, measures changes in electrical impedance in blood cells exposed to plasma salt concentrations of 200 mmol/L—a hyperosmotic stress that mimics the exertion-induced malaise experienced by ME/CFS patients. Comparison of the electrical response of hyperosmotically stressed blood cells from a bedridden ME/CFS patient and healthy control revealed marked differences in impedance changes, providing the basis of a potential diagnostic signature for ME/CFS. The authors validated the signature in a separate cohort of 20 healthy controls and 20 ME/CFS patients of varying disease severity who had been diagnosed by a physician using the established Canadian Consensus Criteria (CCC). Plasma samples used within 5 hours of preparation at 200 cells/µL yielded the most reproducible results. Additionally, the authors paired the assay with a machine-learning algorithm to develop a diagnostic classifier for new ME/CFS patients. According to the authors, though the assay’s mechanistic underpinnings remain unexplored, the findings present a potential blood-based diagnostic biomarker that can complement CCC and aid ME/CFS drug screening efforts.