Cytokine signature associated with disease severity in chronic fatigue syndrome patients, by Jose G. Montoyaa, Tyson H. Holmes, Jill N. Anderson, Holden T. Maecker, Yael Rosenberg-Hasson, Ian J. Valencia, Lily Chu, Jarred W. Younger, Cristina M. Tato, and Mark M. Davis in PNAS July 31, 2017
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) devastates the lives of millions of people and has remained a mystery illness despite decades of research. It has long been suspected that inflammation is central to its pathogenesis.
Although only two cytokines were found to be different (TGF-β higher and resistin lower) in ME/CFS patients compared with controls, 17 cytokines correlated with ME/CFS severity. Thirteen of these cytokines are proinflammatory and may contribute to many of the symptoms these patients experience for several years. Only CXCL9 (MIG) inversely correlated with fatigue duration.
Although some signs of inflammation have been reported previously in patients with myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), the data are limited and contradictory. High-throughput methods now allow us to interrogate the human immune system for multiple markers of inflammation at a scale that was not previously possible. To determine whether a signature of serum cytokines could be associated with ME/CFS and correlated with disease severity and fatigue duration, cytokines of 192 ME/CFS patients and 392 healthy controls were measured using a 51-multiplex array on a Luminex system.
Each cytokine’s preprocessed data were regressed on ME/CFS severity plus covariates for age, sex, race, and an assay property of newly discovered importance: nonspecific binding. On average, TGF-β was elevated (P = 0.0052) and resistin was lower (P = 0.0052) in patients compared with controls. Seventeen cytokines had a statistically significant upward linear trend that correlated with ME/CFS severity:
CCL11 (Eotaxin-1), CXCL1 (GROα), CXCL10 (IP-10), IFN-γ, IL-4, IL-5, IL-7, IL-12p70, IL-13, IL-17F, leptin, G-CSF, GM-CSF, LIF, NGF, SCF, and TGF-α. Of the 17 cytokines that correlated with severity, 13 are proinflammatory, likely contributing to many of the symptoms experienced by patients and establishing a strong immune system component of the disease. Only CXCL9 (MIG) inversely correlated with fatigue duration.