Cellular Immune Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).
Cliff, Jacqueline M, King, Elizabeth C, Lee, Ji-Sook et al. · Frontiers in immunology · 2019 · DOI
Quick Summary
This study examined the immune system of ME/CFS patients by testing their blood for signs of infection and measuring different types of immune cells. Researchers compared 251 ME/CFS patients (including 54 with severe ME/CFS) to healthy people and multiple sclerosis patients. They found that ME/CFS patients had unusual patterns in their T cells—a type of immune cell—but not in natural killer cells, contrary to what some earlier studies suggested.
Why It Matters
This research provides evidence that ME/CFS involves measurable immune system dysfunction, potentially explaining why patients experience frequent infections and prolonged illness. For severely affected patients especially, these findings may help validate that ME/CFS is a biological condition and could eventually guide development of immune-targeted treatments.
Observed Findings
No significant differences in natural killer cell numbers, subtypes, or function between ME/CFS patients and healthy controls
No differences in seroprevalence of six human herpes viruses between ME/CFS and healthy controls
Increased proportion of effector memory CD8+ T cells in ME/CFS patients
Decreased proportion of terminally differentiated effector CD8+ T cells in ME/CFS patients
Significantly elevated mucosal-associated invariant T (MAIT) cells, particularly in severely affected ME/CFS patients
Inferred Conclusions
An altered immunological state exists in ME/CFS, particularly in severely affected individuals, characterized by specific changes in T cell populations
The T cell abnormalities may reflect ongoing or recent infection, or may indicate increased susceptibility to future infections
Natural killer cell dysfunction is not a consistent feature of ME/CFS, contradicting some previous research
Different immune cell populations may be involved in ME/CFS pathophysiology than previously thought
Remaining Questions
Do the observed T cell abnormalities precede ME/CFS onset or develop as a consequence of the illness? (Longitudinal studies needed)
What This Study Does Not Prove
This study cannot determine whether the observed T cell changes cause ME/CFS symptoms or result from ongoing/past infections. It does not establish that immunological dysfunction is present in all ME/CFS patients, nor does it prove that correcting these abnormalities would improve patient outcomes. The cross-sectional design means we cannot determine the temporal sequence of events.