Wednesday, 26 April 2017

Hornig, Lipkin and chronic fatigue syndrome again

Drs Mady Hornig and Ian Lipkin once again provide some fodder for this blog, continuing one of their important research themes on how chronic fatigue syndrome (CFS) (sometimes also referred to as myalgic encephalomyelitis, ME) might show some important immune-related issues [1].

This research tag-team and the teams of dedicated scientists who surround them are making some real progress with regards to the idea that ME/CFS is a physical condition (not psychosomatic and not 'biopsychosocial') with some readily identifiable biological features potentially accompanying cases. Of course we're not there just yet when it comes to a biological test for ME/CFS but science has at least started down that particular research path...

With accompanying media attention in tow (see here), the focus of the most recent results were on how disease sub-types might be important to CFS and specifically, how: "Immune signatures in the central nervous system of ME/CFS patients with atypical features may be distinct from those with more typical clinical presentations."

Authors described how cerebrospinal fluid (CSF) samples from "32 ME/CFS cases with classical features and presentations and 27 ME/CFS cases with atypical features or clinical presentations" were included for analysis. On what basis was 'typical' and 'atypical' described? Well: "The ‘classical’ (C-ME/CFS) group had acute onset of disease marked by a prodrome consistent with infection; ‘atypical’ (A-ME/CFS) ME/CFS patients met full diagnostic criteria for ME/CFS at onset of their illness, but had a less standard onset of ME/CFS and/or developed other disorders after illness onset of ME/CFS." Interestingly one person included in the A-ME/CFS group was described as having Gulf-War Illness (another important condition talked about on this blog).

The results: various cytokines (chemical messengers of the immune system) were assayed for and with some nifty statistical 'corrections' authors reported some potentially important differences between the groups. So: "We found discrete differences in immune signatures of the CNS in ME/CFS subjects with atypical presentations that included sparse inter-cytokine networks and lower levels of two inflammatory mediators, the Th17 cytokine, IL17A, and the IFNγ- and TLR4-induced chemokine, CXCL9." All-in-all results suggested a "less robust CNS immune activation in A-ME/CFS."

Much more research is required in this area for sure. But these results are interesting and pertinent to the idea that within the heterogeneity (where have a I heard that before?) of CFS/ME, there may be quite a few phenotypes and subgroups that might be readily separable with a little biological research effort. Does this therefore mean when we talk about the pluralisation of lots of labels (the autisms, the schizophrenias, the depressions, etc), we might also one day called it 'the chronic fatigue syndromes'? Well, I've kinda speculated about this before in the peer-reviewed domain...

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[1] Hornig M. et al. Immune network analysis of cerebrospinal fluid in myalgic encephalomyelitis/chronic fatigue syndrome with atypical and classical presentations. Transl Psychiatry. 2017 Apr 4;7(4):e1080.

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ResearchBlogging.org Hornig M, Gottschalk CG, Eddy ML, Che X, Ukaigwe JE, Peterson DL, & Lipkin WI (2017). Immune network analysis of cerebrospinal fluid in myalgic encephalomyelitis/chronic fatigue syndrome with atypical and classical presentations. Translational psychiatry, 7 (4) PMID: 28375204