Heat vs. Fatigue: Hyperthermia as a Possible Treatment Option for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

The aetiology and pathophysiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) have not yet been clarified. Its exact diagnosis is also difficult because it has no biomarkers. This lack of knowledge leads to difficulties in treating the disease. In our work, we are attempting to counteract this problem by analysing the central cellular mechanisms in ME/CFS patients and comparing them with those of healthy individuals. This pilot study provides a small glimpse into the journey of nine people with ME/CFS-more specifically, how their peripheral blood mononuclear cells (PBMCs) responded immediately after a session of whole-body hyperthermia (WBH). The clinical effect of WBH has already been investigated in other studies on the treatment of ME/CFS, and these studies have provided valuable insights into its potential benefits. The present study is concerned with the investigation of cellular parameters, namely autophagy, mitochondrial function and mRNA expression, before and after WBH. The results suggest that ME/CFS patients may have higher autophagy-related protein light chain 3 (LC3)-II levels and increased mitochondrial function compared with healthy individuals. A whole-body hyperthermia session could lead to a reduction in LC3-II levels, resulting in a reversion to the levels observed in healthy donors. In the case of mitochondrial parameters, hyperthermia could lead to an increase in the measured parameters. This pilot study is a continuation of a previously published study in which only the isolated cells of ME/CFS patients and a healthy control group were treated with hyperthermia.