Potential of Activin B as a Clinical Biomarker in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), 2021, Gravelsina et al

Abstract
Reliable serum biomarkers are of immense need for diagnostic purposes of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)—a disabling and complex disease for which diagnosis is mainly based on clinical symptoms.

The aim of this study was to evaluate a possible diagnostic potential of activin B by directly comparing 134 cases of ME/CFS with 54 healthy controls. Analyses of human activin B level in plasma samples were performed using a validated human activin B ELISA assay. The results of the study show that activin B levels did not differ statistically significantly between ME/CFS patients and healthy controls (p = 0.6511). No gender or age-related differences in activin B levels were observed in the ME/CFS group and healthy controls. The level of activin B tended to decrease with increasing visual analogue scale score (r = −0.2004; p = 0.5085) nevertheless

the results obtained so far does not support the clinical utility of activin B as a biomarker for ME/CFS.

https://www.mdpi.com/2218-273X/11/8/1189

 

click on tag 'activin' to see the original australian study that proposed activin b as a biomarker.

 

This study uses Fukuda, the previous studies, linked below, on Activin used CCC, which may explain the differing findings.

Activin B is a novel biomarker for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) diagnosis, 2017, Lidbury et al

Rethinking ME/CFS Diagnostic Reference Intervals via Machine Learning & Utility of Activin B for Defining Symptom Severity (2019) Lidbury et al.

 

Not sure if this would explain the difference between studies.

The authors discuss this point as follows:

Here's the main data. Seems like there are lots of participants that are close to the quantification limit.

 

Good that this replication study received support from the Latvian government. The study notes:

https://twitter.com/user/status/1425523490749288448

 

So are they claiming there that both cohorts had 'post-exertional fatigue', which I also assume they believe is equivalent to PEM? Unless there is more detail on their assumptions I remain unconvinced that they are necessarily looking at comparable cohorts.

 

The original study also speaks of "post-exertional fatigue" rather than PEM. Activin B is a novel biomarker for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) diagnosis: a cross sectional study (biomedcentral.com)

I think it is sometimes underestimated how few studies correctly assessed PEM (as PEM is understood in the online patient community).

 

https://twitter.com/user/status/1427180488180047874

 

In the 80s it was recommended that all studies be done on patients who were standing or at least fatigued. I remember one where they did a QEEG (?) where they found a problem in Me patients who were standing against the usual way where they were lying down.

 

The original study finding Activin B biomarker had a significant COI - related to the development of a drug.