Related Studies from the NIH Cohort

1 WASF3 and Mitochondrial Dysfunction (Wang et al. 2023)

Using muscle biopsies from the same NIH intramural cohort, Wang et al. identified a specific molecular mechanism linking cellular stress to exercise intolerance (Wang et al. 2023).

1.1 Key Findings

  • Elevated WASF3 protein: ME/CFS muscle biopsies showed increased WASF3 (Wiskott-Aldrich syndrome protein family member 3)
  • ER stress activation: Endoplasmic reticulum stress was aberrantly increased
  • Mitochondrial localization: WASF3 localizes to mitochondria and disrupts respiratory chain complex assembly
  • Functional consequence: Decreased oxygen consumption and exercise endurance

1.2 Proposed Mechanism

  • Cellular stress activates the unfolded protein response (ER stress)
  • ER stress induces WASF3 expression
  • WASF3 translocates to mitochondria
  • WASF3 disrupts respiratory chain complex IV assembly
  • Impaired oxidative phosphorylation reduces exercise capacity

1.3 Therapeutic Implication

Pharmacologic inhibition of ER stress improved mitochondrial function in patient-derived cells, suggesting a potential therapeutic target.

2 T Cell Exhaustion (Iu et al. 2024)

A separate study examining immune cells from ME/CFS patients found extensive evidence of CD8+ T cell exhaustion (Iu et al. 2024).

2.1 Key Findings

  • Elevated PD-1 expression: Exhaustion marker on CD8+ T cells
  • Transcriptional reprogramming: Gene expression patterns consistent with chronic antigenic stimulation
  • Epigenetic changes: Persistent modifications indicating long-term immune activation
  • Similar to chronic infections: Pattern resembles exhaustion seen in chronic viral infections and cancer

2.2 Implications

T cell exhaustion provides independent confirmation of chronic immune activation in ME/CFS and suggests that immune checkpoint therapies or other approaches to reverse exhaustion might have therapeutic potential.

References

Iu, Derek S, Lauren E Klevorn, Sanjana Bhatt, Sunita Bhatt, et al. 2024. β€œTranscriptional Reprogramming Primes CD8+ T Cells Toward Exhaustion in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.” Proceedings of the National Academy of Sciences 121 (52): e2415119121. https://doi.org/10.1073/pnas.2415119121.
Wang, Ping-yuan, Jin Ma, Young-Chae Kim, et al. 2023. β€œWASF3 Disrupts Mitochondrial Respiration and May Mediate Exercise Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.” Proceedings of the National Academy of Sciences 120 (34): e2302738120. https://doi.org/10.1073/pnas.2302738120.