Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn's disease and chronic fatigue syndrome. — CFSMEATLAS
Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn's disease and chronic fatigue syndrome.
Bourgonje, Arno R, Hörstke, Nicolai V, Fehringer, Michaela et al. · Microbiome · 2024 · DOI
Quick Summary
This study looked at immune responses in ME/CFS and Crohn's disease patients by measuring antibodies against proteins from gut bacteria called flagellins. Researchers found that both patient groups had elevated antibodies against these bacterial proteins, but the pattern of where these antibodies attached differed between the two diseases. These antibody patterns could potentially help doctors diagnose ME/CFS and understand how the immune system may be responding abnormally to gut bacteria.
Why It Matters
This research identifies a potential blood test marker for ME/CFS diagnosis and suggests that abnormal immune responses to gut bacteria may play a role in disease pathogenesis. Understanding these differences between ME/CFS and similar diseases like Crohn's could help develop targeted treatments that restore proper immune tolerance to commensal bacteria.
Observed Findings
Both ME/CFS and Crohn's disease patients showed elevated systemic antibody responses against gut microbiota flagellins compared to healthy controls.
N-terminal antibody binding to Lachnospiraceae flagellins was comparable between ME/CFS and Crohn's disease patients.
C-terminal antibody binding was more prevalent in Crohn's disease patients than ME/CFS patients.
N-terminal antibody-bound flagellin sequences resembled 'stimulator' and 'silent' flagellin types in both diseases.
C-terminal antibody-bound flagellins in Crohn's disease showed higher resemblance to stimulator flagellins, a pattern not observed in ME/CFS.
Inferred Conclusions
Antibody binding to the N-terminal domain of flagellins may similarly disrupt TLR5 activation in both ME/CFS and Crohn's disease, potentially leading to loss of bacterial tolerance.
Disease-specific differences in C-terminal antibody binding suggest distinct pathophysiological mechanisms between ME/CFS and Crohn's disease despite shared gut dysbiosis-related features.
Flagellin-specific antibody profiles have diagnostic potential as serological biomarkers for distinguishing between ME/CFS and other conditions.
Remaining Questions
Do these flagellin antibodies functionally impair TLR5 signaling, and does this contribute to disease pathogenesis or result from it?
What This Study Does Not Prove
This study does not prove that flagellin antibodies cause ME/CFS—it only shows they are associated with the disease. It also does not establish whether these antibodies are a symptom of ME/CFS or a contributing factor. The cross-sectional design cannot determine causality or temporal relationships, and functional effects of antibody-flagellin binding on disease mechanisms remain to be demonstrated.