Exploring the Diagnostic Potential of Immune Biomarker Co-expression in Gulf War Illness Link to paper here * Patients with ME are control in this study Authors: Gordon Broderick, Mary Ann Fletcher, Michael Gallagher, Zachary Barnes, Suzanne D. Vernon, Nancy G. Klimas Abstract Complex disorders like Gulf War illness (GWI) often defy diagnosis on the basis of a single biomarker and may only be distinguishable by considering the co-expression of multiple markers measured in response to a challenge. We demonstrate the practical application of such an approach using an example where blood was collected from 26 GWI, 13 healthy control subjects, and 9 unhealthy controls with chronic fatigue at three points during a graded exercise challenge. A 3-way multivariate projection model based on 12 markers of endocrine and immune function was constructed using a training set of n = 10 GWI and n = 11 healthy controls. These groups were separated almost completely on the basis of two co-expression patterns. In a separate test set these same features allowed for discrimination of new GWI subjects (n = 16) from unhealthy (n = 9) and healthy control subjects with a sensitivity of 70% and a specificity of 90%.
It's pretty impossible to understand just what they found from this brief abstract, I think. I do wish they wouldn't use the phrase 'unhealthy subjects with chronic fatigue'. Do they mean CFS, or ME/CFS, or the symptom chronic fatigue? Given that the researchers include Nancy Klimas who is researching both GWI and ME/CFS, and has said in the past that she has found biological differences in tests between GWI and ME/CFS, and both differ from healthy controls, this seems to be saying the same thing. I wonder whether the headlining of GWI in this study, and only mentioning CF as one of the control groups is because the funding was for a GWI study. I think this is a replication study to see whether their findings from one small study provide reliable diagnostic markers for a second small group.
I think CF here must mean CF and not ME or CFS. Klimas knows the difference. I assume she's pointing out that fatigued patients aren't the same as GWI patients.
p.118 "In this respect it was interesting to note that subjects with CFS, another fatiguing illness, did not manifest this pattern of cytokine co-expression to the same extent as GWI subjects. Indeed only two of the nine CFS controls were assigned to the GWI group by the classification model. Consequently even though metabolic repercussions may be similar, the basic mechanisms driving neuroendocrine-immune dysfunction might be quite different in GWI and these illnesses may constitute very distinct regulatory regimes [47]."