A study published in the February issue of the new journal Science Advances is perhaps the first to identify distinct stages of chronic fatigue syndrome (CFS). Importantly, it demonstrates some immune signatures early in the course of CFS that are not present in subjects with longer duration of illness.
Although efforts were made to identify a specific biological pattern, there are no trustful biomarkers or validated laboratory test for the diagnosis or management of CSF.
In an attempt to discover reliable biological markers related to chronic fatigue syndrome, Mady Hornig and colleagues from the Center for Infection and Immunity at the Columbia University’s Mailman School of Public Health, New York, USA determined the levels of 51 cytokines and chemokines in chronic fatigue syndrome patients from two large multicenter studies.
This is the first study to demonstrate altered plasma immune signatures early in the course of chronic fatigue syndrome that are not present in subjects with longer duration of illness.
In the Science Advances study these authors reported specific cytokine patterns during the early phase (≤3 years) of CSF, including high plasma levels of IL-1α, IL-1RA, IL-4, IL-8, IL-12p40, IL-13, IL-17A, TNF-α and MCP1. Of particular interest was the marked association of interferon (IFN)-γ with the early phase of illness that was detected through logistic regression modeling.
IFNγ is a product of activated T cells [particularly CD8+ and CD4+ T helper 1 (TH1) cells], natural killer cells, as well as activated macrophages in the periphery and microglia in the central nervous system. Some studies in CFS, but not all, have found plasma levels of IFNγ to be elevated, with effects restricted to males in one study.
The Hornig et al. study is consistent with the hypothesis of a viral trigger of this condition and, as discussed by the Center for Infection and Immunity Website at Columbia University, it may also substantiate the idea that ME/CFS reflects an infectious ‘hit-and-run’event. Overall; the study indicates that CSF is an immunological and not a psychological disease.
Early in the course of CFS, as determined by this study, specific immune profiles may have important implications for early diagnosis. This may also suggest new therapeutic and immunomodulatory interventions, which in this condition may be transient or time-limited.