Natural Killer cell deficiency is a consistent finding in ME/CFS patients, in fact some researchers argue that NK (Natural Killer) cell measurement may be a diagnostic aid.
NK cells act as an immune surveillance against invading pathogens. NK cell cytotoxicity (NKCC) has been reported to be decreased in patients with ME/CFS.
journals.plos.org/plosone/a...
Identifying immunological mutations and correlating them with disease progression, symptom severity is an area receiving intense scrutiny.
Particularly vulnerable to opportunistic infections when previously little troubled by ill health that I was far too busy with all the demands of a very active lifestyle.
Immune system signatures mailman.columbia.edu/public... are robust evidence of the biological clinical signs.
That was me hyper system beginning then burned out.
B cell depletion used in the Rituximab trial and strong evidence for mutations of NK cell cytotoxicity indicate a spectrum of immune defects. An autoimmune disease that will require a broad spectrum of tests as time spent affected and severity of reactions, influence expected outcomes.
I have heard the analogy that researchers are looking at a battlefield the immune system has fought upon and are attempting a forensic reconstruction of events using evidence and educated guesswork.
Some idea we are sick before getting very sick please.
Helpful guides for us and our practitioners?
New Funding 
CMRC Strengthened