Current research priorities in chronic fatigue syndrome/myalgic encephalomyelitis: disease mechanisms, a diagnostic test and specific treatments.

Chronic fatigue syndrome (CFS) is an illness characterised by disabling fatigue of at least 6 months duration, which is accompanied by various rheumatological, infectious and neuropsychiatric symptoms. A collaborative study group has been formed to deal with the current areas for development in CFS research--namely, to develop an understanding of the molecular pathogenesis of CFS, to develop a diagnostic test and to develop specific and curative treatments. Various groups have studied the gene expression in peripheral blood of patients with CFS, and from those studies that have been confirmed using polymerase chain reaction (PCR), clearly, the most predominant functional theme is that of immunity and defence. However, we do not yet know the precise gene signature and metabolic pathways involved. Currently, this is being dealt with using a microarray representing 47,000 human genes and variants, massive parallel signature sequencing and real-time PCR. It will be important to ensure that once a gene signature has been identified, it is specific to CFS and does not occur in other diseases and infections. A diagnostic test is being developed using surface-enhanced, laser-desorption and ionisation-time-of-flight mass spectrometry based on a pilot study in which putative biomarkers were identified. Finally, clinical trials are being planned; novel treatments that we believe are important to trial in patients with CFS are interferon-beta and one of the anti-tumour necrosis factor-alpha drugs.

Chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is thought to have a worldwide prevalence of 0.4-1% with approximately 240,000 patients in the UK. Diagnosis is based on clinical criteria and critically depends on exclusion of other physical and psychiatric diseases. Studies of pathogenesis have revealed immune system abnormalities and chronic immune activation, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, brain abnormalities, evidence of emotional stress (comprising host aspects) and evidence of exogenous insults, for example, various microbial infections (Epstein-Barr virus, enteroviruses, parvovirus B19, Coxiella burnetii and Chlamydia pneumoniae), vaccinations and exposure to organophosphate chemicals and other toxins (comprising environmental aspects). Emotional stress appears to be very important as it reduces the ability of the immune system to clear infections, it's presence has been shown to determine whether or not an individual develops symptoms upon virus infection, and it leads to activation of the HPA axis. But, emotional stress is distinct from depression, the presence of which precludes a diagnosis of CFS. There is no specific treatment for CFS other than the much underutilised approach of specific treatment of virus infections. Current priorities are to understand the molecular pathogenesis of disease in terms of human and virus gene expression, to develop a diagnostic test based on protein biomarkers, and to develop specific curative treatments.