“This study delivers what has eluded us for so long: unequivocal evidence of immunological dysfunction in ME/CFS and diagnostic biomarkers for disease” W. Ian Lipkin
Distinct plasma immune signatures in ME/CFS are present early in the illness. Hornig. M. Monotoya, J, Levine, S., Felsenstein, D., Bateman, L, Gottshalk, G….Likpin. L. Sci Adv 27 Feb. 2015.
It’s a major study indeed – the first, I believe, to come out of the Hutchins Foundation’s Chronic Fatigue Initiative and the media is picking it up quickly. The Hutchins Foundation doesn’t mess around. They’re putting $10 million into researching chronic fatigue syndrome. They do big rigorous studies with top researchers.
This study with its carefully selected patients from across the country was loaded with ME/CFS expertise. Besides Mady Hornig and Ian Lipkin of Columbia, Dr. Montoya, Dr. Peterson, Dr. Klimas, Dr. Bateman, Dr. Levine and Dr. Komaroff were listed as co-authors.
“These immune signatures represent the first robust physical evidence that ME/CFS is a biological illness as opposed to a psychological disorder, and the first evidence that the disease has distinct stages.” Columbia University Press Release
Once again we see claims made that finally, finally we have proof that ME/CFS is a biological illness. (The head of the CDC said something similar regarding their study about ten years ago at a National Press Club event.) This time the claim is a bit different, however. This time they have not just evidence but “robust” evidence that ME/CFS is a biological illness.
If the study size is any indicator of robustness – and in a well-designed study it is – their evidence is robust, indeed.
It’s So Big!
This wasn’t just a big study – it was a huge study containing almost 650 patients and healthy controls (298 ME/CFS patients and 348 healthy controls). (A similarly large study is underway at Stanford).
All the patients met both the Fukuda and Canadian Consensus Criteria.
The study wasn’t just big in size – the 51 immune factors it measured meant it was deep as well, and leptin was one of the immune factors measured.
Different But Not Substantive
The study started off on a bit of a downer. Differences in immune factors between the ME/CFS patients and the healthy controls were present, but not “substantive”.
Note, however, almost all the immune factors are lowered – not increased – in the chronic fatigue syndrome patients. We’ll come to a reason for that later.
- Pro-inflammatory – IL171A (p<.0043), CXLC10 (p<.04), TNF-B (p<.0028), Il-6 (p<.04), sFasL (p<.01)
- Anti-inflammatory – Il-10 (p<.024), CSF1 (p<.025)
The one immune factor moderately increased in ME/CFS was leptin (p<.03).
That didn’t mean many in the group hadn’t experienced profound immune alterations, though. They had – earlier…
Hit and Run
“The immunopathology of ME/CFS is not static” the authors.
Further analyses uncovered something the authors freely admitted surprised them. The ME/CFS patient’s immune measures didn’t differ by triggering factor or age or even by sex – they differed by time.
Alterations in over half the immune measures found (combined with some very, very low probability factors that the results weren’t correct) (p< >0002-.0008) indicated that “substantive” differences in immune functioning had existed at one point in time. The short duration patients showed signs of intense immune activation not found in the other groups.
Both the pro and anti-inflammatory sides of the immune system were on high alert early on in ME/CFS.
Immune Differences Between Short-term ME/CFS patients and Healthy Controls:
- • Increased levels in ME/CFS: IL1A, IL1B, IL-6, IL-12, IL-17a, Il-17f, IL-8, TNF-a, sFasL, TRAIL, IFN-y, CCL2, TGFa, CSF, resistin, CCL-11, CSF2, IL1RA, IL-13.
• Reduced Levels in ME/CFS – PDGFBB, CD40L
Cytokine results have been spotty in ME/CFS and that’s been a problem. A few up or down regulated cytokines just don’t raise many eyebrows in the research world. They’re looking for evidence of broad immune alteration – and here it is. I don’t think anybody has seen this kind of sweeping immune activation in ME/CFS before.
Viral Fighter Stands Out
A logistic regression suggested that IFN-y played a particularly significant role in the immune system activation. Produced mostly by natural killer and cytotoxic T-cells – two cells with similar problems in ME/CFS – IFN-y is both an immune stimulator and pathogen inhibitor. (Microglia are big IFN-y producers in the central nervous system).
The IFN-y findings suggest either a pathogen attack or an autoimmune shift may be triggering the immune upregulation seen early in the disease.
High IFN-y levels are associated with Th2 dominance in the immune system and an increased risk of autoimmune processes. Post-viral fatigue has been associated with high IFN-y levels, and alterations in the IFN-y gene have been associated with increased fatigue following infection as well.
IFN-y also showed up in Broderick’s small study examining 16 cytokine levels in adolescents in the first two years after coming down with infectious mononucleosis. Four cytokines IL-8, Il-23, IL-5 and IL-2 were significantly altered or nearly significantly altered.
IFN-y levels were not increased but a computer model suggested it and four other cytokines constituted an immune signature that differentiated people who came down with ME/FS after IM and those who recovered.
Mady Hornig on the Study
IL-5 levels were significantly decreased in ME/CFS patients but IL-5 did not, interestingly enough, make it into the computer model. Further analysis indicated that IL-5 levels were significantly correlated with Il-23 and IFN-y: two cytokines that did make into the model. These cytokines were essentially analogues for IL-5 in the body.
IFN-y also accelerates tryptophan degradation by activating the indoleamine-2,3 deoxygenase enzyme in the kynurenine pathway – Mady Hornig’s favorite pathway. That pathway produces neurotoxic substances that increase production of the excitatory neurotransmitter glutamate that some researchers believe is in play in both fibromyalgia and ME/CFS. Andrew Miller of Emory University has earmarked the kynurenine pathway in ME/CFS.
Cognitive problems and mood changes have been associated with up-r egulation of the kynurenine pathway in diseases ranging from Alzheimer’s to depression. In fact, disruption of the one part or other of the kynurenine pathway occurs in many neurological and psychological disorders.
The authors were confident enough to hypothesize that lesions produced by high IFN-y levels early in the disease are producing the cognitive slowing and depression found in ME/CFS. Andrew Lloyd of the Dubbo project has been suggesting for years that high cytokine loads early in the disease process had disrupted brain functioning, but nobody has gotten this specific before. Now Hornig and Lipkin et. al are proposing a specific mechanism for that: IFN-y produced lesions.
“We propose that IFN-y mediated lesions in kynurenine metabolism may culminate in the depression and psychomotor tardiness (slowed information processing) that contribute to disability in some patients with ME/CFS”.
That kynurenine pathway gets more intriguing when we consider that IFN-y activation and tryptophan degradation has been associated with chronic Epstein-Barr virus infection. Epstein-Barr virus is often associated with infectious mononucleosis – a common trigger of ME/CFS.
CD40L appears to be another early key immune factor. A clear driver of immune functioning in the healthy controls and longer-term ME/CFS patients, CD40l was found to be reduced and strangely disengaged from the immune system in shorter-term ME/CFS patients.
A B-cell maturation regulator, deficiencies in CD40L are associated with recurrent infections and unexplained cognitive issues and CD40 deficient mice exhibit major immune deficiencies. Citing the Fluge/Mella Rituximab study the authors suggested the collapse of this immune factor early in this disease could be important.
One scenario proposed by this study – natural killer and cytotoxic T-cells pumping out IFN-y early in the disease only to collapse later on–appears to fill in some holes that smaller studies would have missed. If this study is representative maybe 20% of the patients in any study have probably had ME/CFS for three years or less. That would mean that the typical low NK dysfunction will show up but the up-regulation early in the disease the authors believe may be contributing to that doesn’t.
Flipping the Switch
That suggests that somewhere around the 3rd year of illness major immune shift occurs. The immune system flips from being hyperactive not to being normal but to being somewhat under active.
Dr. Hornig described a condition of immune system burnout:
“It appears that ME/CFS patients are flush with cytokines until around the three-year mark, at which point the immune system shows evidence of exhaustion and cytokine levels drop.”
There’s something very right about “immune exhaustion” being associated with this disease The fact that many cytokines increased in the early stages of ME/CFS are decreased in the later stages suggests a kind of burnout process is occurring.
Poor natural killer cell functioning in ME/CFS is often described as a type of immune system “burnout” and evidence is emerging of similar cytotoxic T-cell problems as well.
It’s hard for me parse how leptin showed up in this study. The only immune factor increased in the whole ME/CFS group vs the controls, leptin was highlighted in one network analysis of early duration patients and showed up moderately in two others. The authors noted that it was tightly correlated with most of the immune factors later in the disease but not early.
Another cytokine called PDGFBB appeared to be the main driver of the immune reductions later in the disease.
Hit and Run
That suggests the disease has in some way moved on from the immune system. The authors of the paper didn’t have a great explanation for why people remained ill after their immune system activation had died down or had become decreased. If Younger’s findings pan out perhaps the lone elevated immune marker – leptin – found is enough.
A email to Jarred Younger gave a quick answer and a warning that it was not based on a close reading of the paper. He suggested systemic inflammation may drive ME/CFS early on but sensitized microglia and astrocytes in the central nervous system drive it in its later stages. Because we don’t have good ways to test central nervous system inflammation at that point the disease mostly becomes invisible to testing afterwards.
In fact, the authors tantalizingly noted because ME/CFS appears at least in part to be a central nervous disorder cerebral spinal fluid may very well be a better medium to investigate than peripheral blood. That could suggest we’re due some more important findings in a couple of weeks when the Simmaron Research Foundation/Chronic Fatigue Initiative CSF study is published.
The High Cytokine Longer Duration Patients
The study doesn’t make any mention of longer duration patients ME/CFS patients with high cytokine levels. Anecdotal reports from patients indicate they are definitely out there, but this study – involving many quite ill patients being seen at ME/CFS practitioners – suggests that they probably constitute a relatively small subset of patients.
“We now have evidence confirming what millions of people with this disease already know, that ME/CFS isn’t psychological,” Mady Hornig, MD
This large study presents what appears to be almost novel finding in medicine: distinct before and after stages early in a chronic illness. In the early stages of ME/CFS (first 3 years) a distinct and impressive immune activation is present that is followed by modest immune deactivation.
The early immune activation is highly suggested of an infection or some other immune altering process.
The study may ultimately open up possibilities for treating patients with recent onset but provides no possible treatment options at this point for patients who have been sick longer. The more modest immune deactivation found later in the disease suggests that the core causes of the disease are either found elsewhere or were not illuminated by the study.
A major question facing researchers now is finding ways to translate this hit and run immune activation or viral infection into long lasting central nervous system problems. Microglia sensitized by chronic immune activation/kynurenine pathway activity is one possible answer.
Ian Lipkin’s statement that they hope to find important answers in their microbiome study suggests he believes a permanently altered microbiome could provide an answer to that question.
“The question we are trying to address in a parallel microbiome project is what triggers this dysfunction.”Ian Lipkin
The authors statement that cerebral spinal fluid may provide a better medium for understanding this disease could mean we’re in for some interesting findings in a couple of weeks.