Related Experiment Videos
Pathogenic tracks in fatigue syndromes
M Moutschen1, J M Triffaux, J Demonty
1Department of Internal Medicine, CHU Sart-Tilman, Liège, Belgium.
Abstract:
This review analyses the recent literature devoted to two related fatigue syndromes: chronic fatigue syndrome (CFS) and acute onset postviral fatigue syndrome (PVFS). The articles are grouped into five pathogenic tracks: infectious agents, immune system, skeletic muscle, hypothalamo-pituitary-adrenal (HPA) axis and psychiatric factors. Although a particular infectious agent is unlikely to be responsible for all CFS cases, evidence is shown that host-parasite relationships are modified in a large proportion of patients with chronic fatigue. Antibody titres against infectious agents are often elevated and replication of several viruses could be increased. Chronic activation of the immune system is also observed and could be due to the reactivation of persistent or latent infectious agents such as herpes viruses (i.e. HHV-6) or enteroviruses. It could also be favorised by an impaired negative feedback of the HPA axis on the immune system. A model is proposed where the abnormalities of the HPA axis are primary events and are mainly responsible for a chronic activation of the immune system which in turn induces an increased replication of several viruses under the control of cellular transcription factors. These replicating viruses together with cytokines such as TNF-alpha would secondarily induce functional disorders of muscle and several aspects of asthenia itself.
Insights
Chronic fatigue syndromes may stem from immune system activation, potentially triggered by the hypothalamo-pituitary-adrenal (HPA) axis. This activation can lead to increased viral replication and muscle dysfunction, causing fatigue.
Area of Science:
- Neuroimmunology
- Infectious Diseases
- Endocrinology
Background:
- Chronic fatigue syndrome (CFS) and postviral fatigue syndrome (PVFS) are debilitating conditions.
- Pathogenesis involves complex interactions between infectious agents, immune responses, and neuroendocrine factors.
Purpose of the Study:
- To review and synthesize recent literature on the pathogenic mechanisms of CFS and PVFS.
- To explore five key pathogenic tracks: infectious agents, immune system, skeletal muscle, HPA axis, and psychiatric factors.
Main Methods:
- Literature review and analysis of articles on CFS and PVFS.
- Categorization of studies into five pathogenic pathways.
- Development of a proposed model for CFS pathogenesis.
Main Results:
- While no single infectious agent causes all CFS cases, altered host-parasite relationships and elevated antibody titers are common.
- Chronic immune activation, potentially linked to latent infections (e.g., HHV-6, enteroviruses), is observed.
- Abnormalities in the hypothalamo-pituitary-adrenal (HPA) axis may be primary, driving immune activation and viral replication.
Conclusions:
- A proposed model suggests HPA axis dysfunction initiates immune system activation, leading to increased viral replication.
- Replicating viruses and cytokines (e.g., TNF-alpha) contribute to secondary muscle dysfunction and asthenia.
- Understanding these interconnected pathways is crucial for developing effective treatments for chronic fatigue.