Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS.

Area of Science:

• Rheumatology
• Immunology
• Neurology

Background:

• Fatigue is a primary and disabling symptom in primary Sjögren's syndrome (pSS).
• Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) also features fatigue and exertional intolerance.
• Understanding fatigue in pSS and its overlap with ME/CFS is crucial for patient management.

Purpose of the Study:

• To characterize fatigue and associated symptoms in pSS patients.
• To investigate potential symptom overlap between pSS and ME/CFS.
• To identify objective measures for fatigue severity in pSS.

Main Methods:

• Assessed pSS symptom severity and disease activity using questionnaires.
• Evaluated pSS patients against the Canadian Consensus Criteria (CCC) for ME/CFS.
• Measured hand grip strength (HGS) and specific autoantibodies (α1, α2, β1, β2, M3, M4).

Main Results:

• A subgroup of pSS patients reported severe fatigue, pain, depression, and sleep disturbances.
• Four out of eighteen pSS patients met the CCC criteria for ME/CFS.
• HGS correlated with fatigue severity, but unlike ME/CFS, strength recovered post-exertion. Elevated β1, β2, and M4 autoantibodies correlated with disease activity (ESSDAI), not fatigue.

Conclusions:

• Only a small subset of pSS patients meet ME/CFS criteria.
• Post-exertional malaise (PEM) is atypical in pSS, often triggered by mental rather than physical exertion.
• Hand grip strength provides an objective method for assessing fatigue severity in primary Sjögren's syndrome.