I've only read the abstract, but there doesn't seem to be anything of any use here.
People with CFS and the healthy controls didn't have statistically different cortisol levels in saliva throughout the day or in hair.
People with CFS did have a statistically lower 'cortisol awakening response' (4.2 nmol/L vs 6.3 mol/L for the controls).
If you look at the standard deviations given with each average, you can see the very high variation.
(i.e. 4.2 + or - 5.4; 6.1 + or -6.3)
There is a huge overlap in values - some people with CFS had higher values, some healthy controls had lower values. So, even though statistically significant, it is not a very impressive difference.
Ok, so now they give a group of the people with CFS anakinra and a group a placebo for 4 weeks.
I found this study that shows that anakinra is supposed to lower cortisol because it is an IL-1 antagonist.
https://www.endocrine-abstracts.org/ea/0049/ea0049oc11.3
And that is exactly what they found - the people given anakinra did have lower cortisol. Entirely as could be expected. Even though they are measuring the cortisol in hair after 4 weeks - hopefully they got the right hair. (Why did they not report the change in salivary cortisol in the abstract?). And the decrease was a 'slight decrease', as was the decrease in various measures of cortisol observed in the study I linked above. So, it appears that there was nothing odd about the reaction of the people with CFS to the anakinra. Cortisol went down a bit.
And the people on the placebo had higher cortisol - demonstrating that variation in cortisol levels over time is normal.
This study confirms the altered dynamics of the HPA axis in a group of CFS patients, and for the first time shows that this might also be present for long-term cortisol measures.
Huh? There must be something extra in the main text that explains how they can conclude from this study that people with CFS have altered dynamics of the HPA axis. As far as I can see, there is nothing in the abstract that suggest this.
And I can't even work out what they are trying to say with the bolded bit. The authors reported that the cortisol levels in the hair of people with CFS and the healthy controls were not statistically different. So, how is that showing 'altered dynamics of the HPA axis'?
Maybe the full paper will make things clear, but I give them a 'fail' for supporting their conclusion with the data in the abstract.