Natural killer cytotoxicity in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a multi-site,.., of ME/CFS (MCAM) sub-study 2023

authors:

Abstract
Background

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystem illness characterized by substantial reduction in function accompanied by profound unexplained fatigue not significantly relieved by rest, post-exertional malaise, and other symptoms. Reduced natural killer (NK) cell count and cytotoxicity has been investigated as a biomarker for ME/CFS, but few clinical laboratories offer the test and multi-site verification studies have not been conducted.

Methods
We determined NK cell counts and cytotoxicity in 174 (65%) ME/CFS, 86 (32%) healthy control (HC) and 10 (3.7%) participants with other fatigue associated conditions (ill control [IC]) from the Multi-Site Clinical Assessment of ME/CFS (MCAM) study using an assay validated for samples shipped overnight instead of testing on day of venipuncture.

Results
We found a large variation in percent cytotoxicity [mean and (IQR) for ME/CFS and HC respectively, 34.1% (IQR 22.4–44.3%) and 33.6% (IQR 22.9–43.7%)] and no statistically significant differences between patients with ME/CFS and HC (p-value = 0.79). Analysis stratified on illness domain measured with standardized questionnaires did not identify an association of NK cytotoxicity with domain scores. Among all participants, NK cytotoxicity was not associated with survey results of physical and mental well-being, or health factors such as history of infection, obesity, smoking, and co-morbid conditions.

Conclusion
These results indicate this assay is not ready for clinical implementation and studies are needed to further explore immune parameters that may be involved in the pathophysiology of ME/CFS.

https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-03958-2

 

A nail in the coffin.

 

It is time that ME researchers actually said it how it is.
It is not that the assay is not ready for clinical use. It has no apparent relevance to ME.
A - value of 0.79 is impressive - you could bet on getting a result like this by chance and go home rich.

More the laying of the turf over the filled in hole.



At least they did the replication. That is one step forward.

 

I am not saying the study is not valid. However I note that their conclusion is

So they assessed this one assay, from next day delivery and testing. I would have been curious to see whether results were exactly the same comparing to commercial lab (I believe it is Quest lab) or Dr Fletcher's lab (Linked to Dr Klimas) ?

Does this one assay find any differences with healthy control with any other disease?

 

They also looked for abnormal values of NK cytotoxicity in subgroups such as patients with severe ME/CFS or sudden onset ME/CFS but found nothing. There was also no significant correlation between NK cytotoxicity and symptom questionnaires such as subscale scores of SF-36, MFI-20, CDC-SI and PROMIS.