Preprint Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis or control serum, 2025, Ryback et al

[chillier]

Could you test severe ME patients using the same methodology, or are there any hindrances like pre-analytical stuff like handling and processing in time etc? Thank you!

Yep, so to be clear we did have severe pwME in the study, just relatively few. I believe something like 5 severe out of 67 total. If you just look at the severe people only there is still no difference between them and the healthy controls. To get more would have required at home sampling which we couldn't do for this study.

Sample processing would be slower as you say, but probably not that big of a deal.

 

[Kitty]

Congratulations to the whole team for such a well run and thorough study—and big thanks for making it so accessible for participants with ME/CFS.

 

[hotblack]

Seems very thorough to me so far.

Normalising for cell count is an interesting addition that they didn’t do in Fluge et al (2016). And could explain a lot.

Beyond that sample size is obviously the clearest difference.

This study also seems to use only women which could be a difference?

Fluge said there was a significant difference in amino acid profiles between men and women but I’m unsure if they tested men and women for cellular metabolism. From a brief look at that paper the precise details of the subgroup of 12 cases tested is unclear.

Fluge collected samples at different points, from different studies and there were 200 patients in total. But only 12 used for cellular metabolism tests. So maybe there’s also some potential for variations in sample handling? “The blood samples were collected before intervention (baseline) in three separate clinical trials.“

Fluge was doing a lot of stuff simultaneously and over different groups and timeframes which potentially confuses things, while this focuses clearly on one area and seems to do so very consistently and thoroughly.

 

[ME/CFS Skeptic]

Just read the full text and it is great to see the methodological quality of the study.

They used blinding, randomization, pre-registration of the analysis plan. They graphs are clear, the statistical models are reported explicitly, there's a good overview of potential limitations. No long discussion section, but all straight to the point.

Well done.

 

[forestglip]

Agree with other posters - very well written and thorough.

I wonder if the diagnostic criteria might be a factor. CCC in Fluge et al, but CCC and/or IOM here, so maybe the factor in the blood wasn't necessarily related to ME/CFS, but was related to a comorbidity required by CCC but not by IOM.

 

[Eddie]

Agree with other posters - very well written and thorough.

I wonder if the diagnostic criteria might be a factor. CCC in Fluge et al, but CCC and/or IOM here, so maybe the factor in the blood wasn't necessarily related to ME/CFS, but was related to a comorbidity required by CCC but not by IOM.

I doubt it, I think the vast majority of people that meet IOM criteria would also meet the CCC criteria. Perhaps there is a difference in the cohorts but it wouldn't be a result of using CCC or CCC and/or IOM. These diagnostic categories allow differences between ME/CFS patients even if they were only using one criteria anyways.

 

[Simon M]

This detail would have been my first thought about the discrepancy between findings. It is extremely admirable to have this level of consideration for participants, though it is a shame that it might skew the ability to replicate findings in this way.

I don't know how significant this is. I quite often don't have symptoms at rest, but I always have the problem of minimal exertion exhausting me. In other words, if the problem was that something in my blood was stopping my mitochondria working properly, I would've expected that something in the blood to be there all the time. Though there might well be more of it during PEM.

I don't know if we have any kind of functional measure of participants, e.g. SF 36 physical function score, but I have thought many would have been physically stressed by going to the lab and having the sample taken.

(Sorry, not well enough to have read the paper yet)

 

[hotblack]

I don't know how significant this is. Eight quite often don't have symptoms at rest, but I always have the problem of minimal exertion exhausting me.

Same. I think I’ve discussed this with @jnmaciuch before and our experiences appear to be quite different wrt PEM triggering.

And if the changes in blood were only visible in people after triggering PEM presumably this would then be measuring some other, downstream effect of what happens to us? Still interesting but not the ‘something in the blood’ cause talked about originally?

 

[hotblack]

Pretty much every question that popped into my head while going through this paper was answered in this paper. That gives me faith in the results.

While I have more unanswered questions after going back to Fluge et al 2016. Which I suppose makes sense, Fluge was more exploratory, this was looking at confirmation.

A couple of other notes while listening..

What would the results have looked like if you didn’t correct for cell count?
This seems to be covered in point 4 of the discussion

However, no differences in cell counts were observed between ME and HC, so are unlikely to have contributed to ME serum effects previously observed by Fluge et al.

However I don’t think we have numbers on cell count for Fluge et al? (Another unknown, along with some specifics of the sub-group they tested mentioned in my previous post).

HCs seem to have more variation in OCR (Figure 3A), particularly with lower longer tails, I wonder if this means Fluge could have by chance had a group with lower levels, given the small sample size, while ME seems a little more cohesive/clumped together? Sorry this isn’t statistically very sound, not my strong point, maybe someone who is better at that can see if his is relevant.

How much would the specifics of the target muscle cells change things? There seem to be differences in absolute values compared to Fluge, presumably different people’s myoblasts perform a bit differently? What effects could there be here? Could only some people’s myoblasts be affected? That is, there be something in the blood *and* something in muscle tissue?
This seems partially covered in discussion point 1

While genetic differences in the HSMM cells could have altered their susceptibility to ME serum, it is reasonable to expect that the assay would be generalisable to other healthy HSMMs beyond those used in the original study.

 

[jnmaciuch]

In other words, if the problem was that something in my blood was stopping my mitochondria working properly, I would've expected that something in the blood to be there all the time. Though there might well be more of it during PEM.

Just to clarify—my speculation was that it would be something produced by muscle cells (and possibly other tissues) which may leak out into the blood to physiologically relevant levels only if production is amplified enough. Though again, this is only one speculation, could be many other explanations based in methodological differences.

 

[jnmaciuch]

Just read the full text and it is great to see the methodological quality of the study.

They used blinding, randomization, pre-registration of the analysis plan. They graphs are clear, the statistical models are reported explicitly, there's a good overview of potential limitations. No long discussion section, but all straight to the point.

Well done.

Agree! Definitely deserves the commendation