Peter D White

Comment on “Detection of an Infectious Retrovirus, XMRV, in Blood Cells of Patients with Chronic Fatigue Syndrome”

Viral Link to Chronic Fatigue Chronic fatigue syndrome (CFS) is a complex and debilitating disorder that is often linked to immune system dysfunction but whose cause(s) remain mysterious. Lombardi et al. (p. 585, published online 8 October; see the Perspective by Coffin and Stoye) now present a tantalizing new lead. In blood samples from 101 patients with well-documented CFS, over two-thirds (68) contained DNA from a recently described human gammaretrovirus, xenotropic murine leukemia virus–related virus (XMRV), which possesses sequence similarity to a murine leukemia virus. Cell culture assays confirmed that XMRV derived from CFS patient plasma and from T and B lymphocytes was infectious. Although the correlation with CFS is striking, whether the virus plays a causal role in the disorder remains to be determined. Interestingly, nearly 4% of the 218 healthy donors tested were positive for XMRV, which suggests that this virus—whose pathogenic potential is unknown—may be present in a significant proportion of the general population. Two-thirds of a sample of 101 U.S. patients with chronic fatigue syndrome harbor an infectious retrovirus in their blood cells. Chronic fatigue syndrome (CFS) is a debilitating disease of unknown etiology that is estimated to affect 17 million people worldwide. Studying peripheral blood mononuclear cells (PBMCs) from CFS patients, we identified DNA from a human gammaretrovirus, xenotropic murine leukemia virus–related virus (XMRV), in 68 of 101 patients (67%) as compared to 8 of 218 (3.7%) healthy controls. Cell culture experiments revealed that patient-derived XMRV is infectious and that both cell-associated and cell-free transmission of the virus are possible. Secondary viral infections were established in uninfected primary lymphocytes and indicator cell lines after their exposure to activated PBMCs, B cells, T cells, or plasma derived from CFS patients. These findings raise the possibility that XMRV may be a contributing factor in the pathogenesis of CFS.

Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution

BackgroundChronic fatigue syndrome (CFS) is defined by symptoms and disability, has no confirmatory physical signs or characteristic laboratory abnormalities, and the etiology and pathophysiology remain unknown. Difficulties with accurate case ascertainment contribute to this ignorance.MethodsExperienced investigators from around the world who are involved in CFS research met for a series of three day workshops in 2000, 2001 and 2002 intended to identify the problems in application of the current CFS case definition. The investigators were divided into focus groups and each group was charged with a topic. The investigators in each focus group relied on their own clinical and scientific knowledge, brainstorming within each group and with all investigators when focus group summaries were presented. Relevant literature was selected and reviewed independent of the workshops. The relevant literature was circulated via list-serves and resolved as being relevant by group consensus. Focus group reports were analyzed and compiled into the recommendations presented here.ResultsAmbiguities in the current CFS research definition that contribute to inconsistent case identification were identified. Recommendations for use of the definition, standardization of classification instruments and study design issues are presented that are intended to improve the precision of case ascertainment. The International CFS Study Group also identified ambiguities associated with exclusionary and comorbid conditions and reviewed the standardized, internationally applicable instruments used to measure symptoms, fatigue intensity and associated disability.ConclusionThis paper provides an approach to guide systematic, and hopefully reproducible, application of the current case definition, so that case ascertainment would be more uniform across sites. Ultimately, an operational CFS case definition will need to be based on empirical studies designed to delineate the possibly distinct biological pathways that result in chronic fatigue.

Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis

BACKGROUND Certain infections can trigger chronic fatigue syndromes (CFS) in a minority of people infected, but the reason is unknown. We describe some factors that predict or are associated with prolonged fatigue after infectious mononucleosis and contrast these factors with those that predicted mood disorders after the same infection. METHODS We prospectively studied a cohort of 250 primary-care patients with infectious mononucleosis or ordinary upper-respiratory-tract infections until 6 months after clinical onset. We sought predictors of both acute and chronic fatigue syndromes and mood disorders from clinical, laboratory, and psychosocial measures. FINDINGS An empirically defined fatigue syndrome 6 months after onset, which excluded comorbid psychiatric disorders, was most reliably predicted by a positive Monospot test at onset (odds ratio 2.1 [95% CI 1.4-3.3]) and lower physical fitness (0.35 [0.15-0.8]). Cervical lymphadenopathy and initial bed rest were associated with, or predicted, a fatigue syndrome up to 2 months after onset. By contrast, mood disorders were predicted by a premorbid psychiatric history (2.3 [1.4-3.9]), an emotional personality score (1.21 [1.11-1.35]), and social adversity (1.7 [1.0-2.9]). Definitions of CFS that included comorbid mood disorders were predicted by a mixture of those factors that predicted either the empirically defined fatigue syndrome or mood disorders. INTERPRETATION The predictors of a prolonged fatigue syndrome after an infection differ with both definition and time, depending particularly on the presence or absence of comorbid mood disorders. The particular infection and its consequent immune reaction may have an early role, but physical deconditioning may also be important. By contrast, mood disorders are predicted by factors that predict mood disorders in general.

Strength and physiological response to exercise in patients with chronic fatigue syndrome

OBJECTIVE To measure strength, aerobic exercise capacity and efficiency, and functional incapacity in patients with chronic fatigue syndrome (CFS) who do not have a current psychiatric disorder. METHODS Sixty six patients with CFS without a current psychiatric disorder, 30 healthy but sedentary controls, and 15 patients with a current major depressive disorder were recruited into the study. Exercise capacity and efficiency were assessed by monitoring peak and submaximal oxygen uptake, heart rate, blood lactate, duration of exercise, and perceived exertion during a treadmill walking test. Strength was measured using twitch interpolated voluntary isometric quadriceps contractions. Symptomatic measures included physical and mental fatigue, mood, sleep, somatic amplification, and functional incapacity. RESULTS Compared with sedentary controls, patients with CFS were physically weaker, had a significantly reduced exercise capacity, and perceived greater effort during exercise, but were equally unfit. Compared with depressed controls, patients with CFS had significantly higher submaximal oxygen uptakes during exercise, were weaker, and perceived greater physical fatigue and incapacity. Multiple regression models suggested that exercise incapacity in CFS was related to quadriceps muscle weakness, increased cardiovascular response to exercise, and body mass index. The best model of the increased exercise capacity found after graded exercise therapy consisted of a reduction in submaximal heart rate response to exercise. CONCLUSIONS Patients with CFS were weaker than sedentary and depressed controls and as unfit as sedentary controls. Low exercise capacity in patients with CFS was related to quadriceps muscle weakness, low physical fitness, and a high body mass ratio. Improved physical fitness after treatment was associated with increased exercise capacity. These data imply that physical deconditioning helps to maintain physical disability in CFS and that a treatment designed to reverse deconditioning helps to improve physical function.

Is there a better term than "medically unexplained symptoms"?

The European Association of Consultation Liaison Psychiatry and Psychosomatics (EACLPP) is preparing a document aimed at improving the quality of care received by patients who have “medically unexplained symptoms” or “somatisation” [1]. Part of this document identifies barriers to improved care and it has become apparent that the term “medically unexplained symptoms” is itself a barrier to improved care. This is because the term is not acceptable to some patients and doctors. It defines the patients symptoms by what they are not, rather than by what they are, and it reflects dualistic thinking – regarding symptoms as either “organic” or “non-organic”/“psychological”. The authors of this paper met in Manchester in May 2009 to review thoroughly this problem of terminology and make recommendations for a better term.. The deliberations of the group form the basis of this paper. Our discussion concerned terminology applicable to the more severe and persistent common symptoms of unknown aetiology, so often seen in primary care, and the recognised disorders, which present with symptoms that escape orthodox medical or surgical disease explanations. The latter include the disorders currently listed in the Somatoform disorders chapters of the American Diagnostic and Statistical Manual of Mental Disorders (DSM) and the WHO International Classification of Diseases (ICD). Our priority was to identify a term or terms that would facilitate management – that is it would encourage joint medical psychiatric/psychological assessment and treatment and be acceptable to physicians, patients, psychiatrists and psychologists. In the first step, we reviewed why the term “medically unexplained symptoms” is so often unhelpful. In the second step we established a set of criteria which may be used to judge any alternative term. In the third step we applied these criteria to the various terms which have been used to describe this group of complaints.

Is a full recovery possible after cognitive behavioural therapy for chronic fatigue syndrome

Background: Cognitive behavioural therapy (CBT) for chronic fatigue syndrome (CFS) leads to a decrease in symptoms and disabilities. There is controversy about the nature of the change following treatment; some suggest that patients improve by learning to adapt to a chronic condition, others think that recovery is possible. The objective of this study was to find out whether recovery from CFS is possible after CBT. Methods: The outcome of a cohort of 96 patients treated for CFS with CBT was studied. The definition of recovery was based on the absence of the criteria for CFS set up by the Center for Disease Control (CDC), but also took into account the perception of the patients’ fatigue and their own health. Data from healthy population norms were used in calculating conservative thresholds for recovery. Results: After treatment, 69% of the patients no longer met the CDC criteria for CFS. The percentage of recovered patients depended on the criteria used for recovery. Using the most comprehensive definition of recovery, 23% of the patients fully recovered. Fewer patients with a co-morbid medical condition recovered. Conclusion: Significant improvement following CBT is probable and a full recovery is possible. Sharing this information with patients can raise the expectations of the treatment, which may enhance outcomes without raising false hopes.

Is perfectionism associated with fatigue

Perfectionism has been implicated as a vulnerability factor in the development of chronic unexplained fatigue. In the present study, different components of fatigue and perfectionism were studied in 121 female nurses. They completed a postal questionnaire assessing current (state) and usual (trait) fatigue, and dimensions of personality including six components of perfectionism. Night-shift work was associated with state, but not trait, fatigue. Negative, but not positive, components of perfectionism were associated with mental trait fatigue in particular, but also with physical trait fatigue. In contrast, the associations with positive perfectionism tended to be inverse. Multiple regression modeling indicated that neuroticism as well as negative perfectionism were separately associated with trait fatigue. We suggest that negative aspects of perfectionism may cause maladaptive coping strategies which predispose individuals to fatigue.

How to assess common somatic symptoms in large-scale studies: A systematic review of questionnaires

OBJECTIVE Many questionnaires for assessment of common somatic symptoms or functional somatic symptoms are available and their use differs greatly among studies. The prevalence and incidence of symptoms are partially determined by the methods used to assess them. As a result, comparison across studies is difficult. This article describes a systematic review of self-report questionnaires for somatic symptoms for use in large-scale studies and recommends two questionnaires for use in such studies. METHODS A literature search was performed in the databases Medline, PsycINFO and EMBASE. Articles that reported the development, evaluation, or review of a self-report somatic symptom measure were included. Instrument evaluation was based on validity and reliability, and their fitness for purpose in large scale studies, according to the PhenX criteria. RESULTS The literature search identified 40 questionnaires. The number of items within the questionnaires ranged from 5 to 78 items. In 70% of the questionnaires, headaches were included, followed by nausea/upset stomach (65%), shortness of breath/breathing trouble (58%), dizziness (55%), and (low) back pain/backaches (55%). Data on validity and reliability were reported and used for evaluation. CONCLUSION Questionnaires varied regarding usability and burden to participants, and relevance to a variety of populations and regions. Based on our criteria, the Patient Health Questionnaire-15 and the Symptom Checklist-90 somatization scale seem the most fit for purpose for use in large-scale studies. These two questionnaires have well-established psychometric properties, contain relevant symptoms, are relatively short, and are available in multiple languages.

A systematic review of chronic fatigue, its syndromes and ethnicity: prevalence, severity, co-morbidity and coping

BACKGROUND Chronic Fatigue Syndrome (CFS) is characterized by unexplained fatigue that lasts for at least 6 months alongside a constellation of other symptoms. CFS was historically thought to be most common among White women of higher socio-economic status. However, some recent studies in the USA suggest that the prevalence is actually higher in some minority ethnic groups. If there are convincing differences in prevalence and risk factors across all or some ethnic groups, investigating the causes of these can help unravel the pathophysiology of CFS. METHODS A systematic review was conducted to explore the relationship between fatigue, chronic fatigue (CF--fatigue lasting for 6 months), CFS and ethnicity. Studies were population-based and health service-based. Meta-analysis was also conducted to examine the population prevalence of CF and CFS across ethnic groups. RESULTS Meta-analysis showed that compared with the White American majority, African Americans and Native Americans have a higher risk of CFS [Odds Ratio (OR) 2.95, 95% confidence interval (CI): 0.69-10.4; OR = 11.5, CI: 1.1-56.4, respectively] and CF (OR = 1.56, CI: 1.03-2.24; OR = 3.28, CI: 1.63-5.88, respectively). Minority ethnic groups with CF and CFS experience more severe symptoms and may be more likely to use religion, denial and behavioural disengagement to cope with their condition compared with the White majority. CONCLUSIONS Although available studies and data are limited, it does appear that some ethnic minority groups are more likely to suffer from CF and CFS compared with White people. Ethnic minority status alone is insufficient to explain ethnic variation of prevalence. Psychosocial risk factors found in high-risk groups and ethnicity warrant further investigation to improve our understanding of aetiology and the management of this complex condition.

The existence of a fatigue syndrome after glandular fever

This prospective cohort study was designed to test whether a distinct fatigue syndrome existed after the onset of glandular fever. Two hundred and fifty primary care patients, with either glandular fever or an ordinary upper respiratory tract infection (URTI) were interviewed three times in the 6 months after the clinical onset of their infection. At each interview a standardized psychiatric interview was given and physical symptoms were assessed. There were 108 subjects with and Epstein-Barr virus (EBV) infection; 83 subjects had glandular fever not caused by EBV and 54 subjects had an ordinary URTI. Five subjects were excluded because they had no evidence of an infection. Principal components analyses of symptoms supported the existence of a fatigue syndrome, particularly in the two glandular fever groups. The addition of symptoms not elicited by the standard interviews gave the full syndrome. This included physical and mental fatigue, excessive sleep, psychomotor retardation, poor concentration, anhedonia, irritability, social withdrawal, emotional lability, and transient sore throat and neck gland swelling with pain. A fatigue syndrome probably exists after glandular fever.