Findings from a clinical and laboratory database developed for discovery of pathogenic mechanisms in myalgic encephalomyelitis/chronic fatigue syndrome
Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, chronic illness that is often disabling. This paper introduces the Chronic Fatigue Initiative, which conducted a large multi-center study to more fully characterize ME/CFS and ultimately to describe and understand the underlying mechanisms and pathogenesis of this illness. Methods: A total of 203 patients with ME/CFS (cases) and 202 matched healthy controls (HCs) were enrolled from 5 geographically different expert clinical sites to create a well-characterized population linked to a national biorepository. ME/CFS subjects were compared to a one-to-one matched HC population for analyses of symptoms and illness severity. Cases were further evaluated for frequency and severity of symptoms and symptom clusters, and the effects of illness duration and acute vs. gradual onset. Results: This study collected more than 4000 pieces of data from each subject in the study. Marked impairment was demonstrated for cases vs. controls. Symptoms of fatigue were identified, but also, nearly as frequent and severe, were symptoms of cognitive dysfunction, inflammation, pain and autonomic dysfunction. Potential subgrouping strategies were suggested by these identified symptom clusters: sleep, neurocognitive, autonomic, inflammatory, neuroinflammatory, gastrointestinal and endocrine symptoms. Conclusions: Clearly, ME/CFS is not simply a state of chronic fatigue. These data indicate that fatigue severity is matched by cognitive, autonomic, pain, inflammatory and neuroinflammatory symptoms as the predominant clinical features. These findings may assist in the clarification and validation of case definitions. In addition, the data can aid clinicians in recognizing and understanding the overall illness presentation. Framing ME/CFS as a multisystem disorder may assist in developing therapies targeting the multifaceted domains of illness.
A multicenter blinded analysis indicates no association between chronic fatigue syndrome/myalgic encephalomyelitis and either xenotropic murine leukemia virus-related virus or polytropic murine leukemia virus
The disabling disorder known as chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) has been linked in two independent studies to infection with xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (pMLV). Although the associations were not confirmed in subsequent studies by other investigators, patients continue to question the consensus of the scientific community in rejecting the validity of the association. Here we report blinded analysis of peripheral blood from a rigorously characterized, geographically diverse population of 147 patients with CFS/ME and 146 healthy subjects by the investigators describing the original association. This analysis reveals no evidence of either XMRV or pMLV infection. IMPORTANCE Chronic fatigue syndrome/myalgic encephalomyelitis has an estimated prevalence of 42/10,000 in the United States, with annual direct medical costs of $7 billion. Here, the original investigators who found XMRV and pMLV (polytropic murine leukemia virus) in blood of subjects with this disorder report that this association is not confirmed in a blinded analysis of samples from rigorously characterized subjects. The increasing frequency with which molecular methods are used for pathogen discovery poses new challenges to public health and support of science. It is imperative that strategies be developed to rapidly and coherently address discoveries so that they can be carried forward for translation to clinical medicine or abandoned to focus resource investment more productively. Our study provides a paradigm for pathogen dediscovery that may be helpful to others working in this field.