A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome

Plasma cytokine levels reveal deficiencies in IL-8 and gamma interferon in Long-COVID

Up to half of individuals who contract SARS-CoV-2 develop symptoms of long-COVID approximately three months after initial infection. These symptoms are highly variable, and the mechanisms inducing them are yet to be understood. We compared plasma cytokine levels from individuals with long-COVID to healthy individuals and found that those with long-COVID had 100% reductions in circulating levels of interferon gamma (IFNγ) and interleukin-8 (IL-8). Additionally, we found significant reductions in levels of IL-6, IL-2, IL-17, IL-13, and IL-4 in individuals with long-COVID. We propose immune exhaustion as the driver of long-COVID, with the complete absence of IFNγ and IL-8 preventing the lungs and other organs from healing after acute infection, and reducing the ability to fight off subsequent infections, both contributing to the myriad of symptoms suffered by those with long-COVID.

Risk of rheumatic disease in breast implant users: a qualitative systematic review

Background

Recent studies on the risk of rheumatic disease among breast implant users have reported conflicting results. The primary objective of this study was to provide a systematic and critical review of the literature on the association between breast implants and the risk of rheumatic disease.

Methods

A qualitative systematic review was conducted in PubMed, MEDLINE, EMBASE, EBM-Reviews and CINAHL Complete from database inception to June 23rd, 2021. Eligible papers were full-length articles in English or French reporting original data on the incident risk of rheumatic disease among individuals with and without breast implants. Data were extracted from published reports and appraised using the Newcastle-Ottawa scale. The main outcome was incident risk of systemic sclerosis (SSc), Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), fibromyalgia and other rheumatic disorders and symptoms.

Results

Out of 3,425 identified citations, 86 met inclusion criteria. Two cohort studies suggested a two-fold increase in risk of SSc, whereas three case-control studies showed no increase in risk. Three cohort studies did not find an increased risk of incident and confirmed SS among breast implant users, however symptoms of sicca, myalgia and fatigue were reported more frequently. A meta-analysis of heterogenous studies reported a less than two-fold increase in risk of RA. Studies did not support an association with SLE. Insufficient evidence was available for autoimmune myositis and other rheumatic diseases. Implant rupture detected on imaging was not clearly associated with incident rheumatic disease, although no studies specifically examined the risk associated with acute/traumatic rupture. Little data was available on the safety of saline breast implants. Explantation often led to temporary improvement.

Conclusions

Based on a small number of high-quality and methodologically robust studies, an association between breast implants and a small increase in risk of SSc and RA could not be excluded. Symptoms of sicca, myalgia and fatigue were reported more frequently among breast implant users. Overall, there remains much uncertainty in regard to the association between breast implants and the risk of incident rheumatic diseases. Individuals considering the placement of breast implants should be informed of this uncertainty.

Trial Registration

This study was registered in the PROSPERO database (#CRD42019133616).

Meta-analysis investigating post-exertional malaise between patients and controls

Post-exertional malaise is either required or included in many previously proposed case definitions of myalgic encephalomyelitis/chronic fatigue syndrome. A meta-analysis of odds ratios (ORs; association between patient status and post-exertional malaise status) and a number of potential moderators (i.e. study-level characteristics) of effect size were conducted. Post-exertional malaise was found to be 10.4 times more likely to be associated with a myalgic encephalomyelitis/chronic fatigue syndrome diagnosis than with control status. Significant moderators of effect size included patient recruitment strategy and control selection. These findings suggest that post-exertional malaise should be considered a cardinal symptom of myalgic encephalomyelitis/chronic fatigue syndrome.

Inflammatory proteins are altered in chronic fatigue syndrome-A systematic review and meta-analysis

Immune dysfunction has been posited as a key element in the aetiology of chronic fatigue syndrome (CFS) since the illness was first conceived. However, systematic reviews have yet to quantitatively synthesise inflammatory biomarkers across the literature. We undertook a systematic review and meta-analysis to quantify available data on circulating inflammatory proteins, examining studies recruiting patients with a CFS diagnosis and a non-affected control group. Results were meta-analysed from 42 studies. Patients with CFS had significantly elevated tumour necrosis factor (ES = 0.274, p < 0.001), interleukin-2 (ES = 0.203, p = 0.006), interleukin-4 (ES = 0.373, p = 0.004), transforming growth factor-β (ES = 0.967, p < 0.001) and c-reactive protein (ES = 0.622, p = 0.019). 12 proteins did not differ between groups. These data provide some support for an inflammatory component in CFS, although inconsistency of results indicates that inflammation is unlikely to be a primary feature in all those suffering from this disorder. It is hoped that further work will elucidate whether there are subgroups of patients with clinically-relevant inflammatory dysfunction, and whether inflammatory cytokines may provide a prognostic biomarker or moderate treatment effects.

Neuroinflammation and Cytokines in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Critical Review of Research Methods

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is the label given to a syndrome that can include long-term flu-like symptoms, profound fatigue, trouble concentrating, and autonomic problems, all of which worsen after exertion. It is unclear how many individuals with this diagnosis are suffering from the same condition or have the same underlying pathophysiology, and the discovery of biomarkers would be clarifying. The name "myalgic encephalomyelitis" essentially means "muscle pain related to central nervous system inflammation" and many efforts to find diagnostic biomarkers have focused on one or more aspects of neuroinflammation, from periphery to brain. As the field uncovers the relationship between the symptoms of this condition and neuroinflammation, attention must be paid to the biological mechanisms of neuroinflammation and issues with its potential measurement. The current review focuses on three methods used to study putative neuroinflammation in ME/CFS: (1) positron emission tomography (PET) neuroimaging using translocator protein (TSPO) binding radioligand (2) magnetic resonance spectroscopy (MRS) neuroimaging and (3) assays of cytokines circulating in blood and cerebrospinal fluid. PET scanning using TSPO-binding radioligand is a promising option for studies of neuroinflammation. However, methodological difficulties that exist both in this particular technique and across the ME/CFS neuroimaging literature must be addressed for any results to be interpretable. We argue that the vast majority of ME/CFS neuroimaging has failed to use optimal techniques for studying brainstem, despite its probable centrality to any neuroinflammatory causes or autonomic effects. MRS is discussed as a less informative but more widely available, less invasive, and less expensive option for imaging neuroinflammation, and existing studies using MRS neuroimaging are reviewed. Studies seeking to find a peripheral circulating cytokine "profile" for ME/CFS are reviewed, with attention paid to the biological and methodological reasons for lack of replication among these studies. We argue that both the biological mechanisms of cytokines and the innumerable sources of potential variance in their measurement make it unlikely that a consistent and replicable diagnostic cytokine profile will ever be discovered.

Exercise and the Athlete With Infectious Mononucleosis

OBJECTIVE

To determine appropriate management of the active individual with infectious mononucleosis (IM), including issues of diagnosis, the determination of splenomegaly, and other measures of disease status, the relationship of the disease to chronic fatigue syndrome (CFS), and the risks of exercise at various points in the disease process.

DATA SOURCES

An Ovid/MEDLINE search (January 1996-June 2015) was widely supplemented by "similar articles" found in Ovid/MEDLINE and PubMed, reference lists, and personal files.

MAIN RESULTS

Clinical diagnoses of IM are unreliable. Traditional laboratory indicators (lymphocytosis, abnormal lymphocytes, and a heterophile-positive slide test) can be supplemented by more sensitive and more specific but also more costly Epstein-Barr antigen determinations. Clinical estimates of splenomegaly are fallible. Laboratory determinations, commonly by 2D ultrasonography, must take account of methodology, the formulae used in calculations and the individual's body size. The SD of normal values matches the typical increase of size in IM, but repeat measurements can help to monitor regression of the disease. The main risks to the athlete are spontaneous splenic rupture (seen in 0.1%-0.5% of patients and signaled by acute abdominal pain) and progression to chronic fatigue, best avoided by 3 to 4 weeks of restricted activity followed by graded reconditioning. A full recovery of athletic performance is usual with 2 to 3 months of conservative management.

CONCLUSIONS

Infectious mononucleosis is a common issue for young athletes. But given accurate diagnosis and the avoidance of splenic rupture and progression to CFS through a few weeks of restricted activity, long-term risks to the health of athletes are few.

Chronic fatigue syndrome and circulating cytokines: A systematic review

There has been much interest in the role of the immune system in the pathophysiology of chronic fatigue syndrome (CFS), as CFS may develop following an infection and cytokines are known to induce acute sickness behaviour, with similar symptoms to CFS. Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines, a search was conducted on PubMed, Web of Science, Embase and PsycINFO, for CFS related-terms in combination with cytokine-related terms. Cases had to meet established criteria for CFS and be compared with healthy controls. Papers retrieved were assessed for both inclusionary criteria and quality. 38 papers met the inclusionary criteria. The quality of the studies varied. 77 serum or plasma cytokines were measured without immune stimulation. Cases of CFS had significantly elevated concentrations of transforming growth factor-beta (TGF-β) in five out of eight (63%) studies. No other cytokines were present in abnormal concentrations in the majority of studies, although insufficient data were available for some cytokines. Following physical exercise there were no differences in circulating cytokine levels between cases and controls and exercise made no difference to already elevated TGF-β concentrations. The finding of elevated TGF-β concentration, at biologically relevant levels, needs further exploration, but circulating cytokines do not seem to explain the core characteristic of post-exertional fatigue.

Chronic coinfections in patients diagnosed with chronic lyme disease: a systematic review

PURPOSE

Often, the controversial diagnosis of chronic Lyme disease is given to patients with prolonged, medically unexplained physical symptoms. Many such patients also are treated for chronic coinfections with Babesia, Anaplasma, or Bartonella in the absence of typical presentations, objective clinical findings, or laboratory confirmation of active infection. We have undertaken a systematic review of the literature to evaluate several aspects of this practice.

METHODS

Five systematic literature searches were performed using Boolean operators and the PubMed search engine.

RESULTS

The literature searches did not demonstrate convincing evidence of: 1) chronic anaplasmosis infection; 2) treatment-responsive symptomatic chronic babesiosis in immunocompetent persons in the absence of fever, laboratory abnormalities, and detectable parasitemia; 3) either geographically widespread or treatment-responsive symptomatic chronic infection with Babesia duncani in the absence of fever, laboratory abnormalities, and detectable parasitemia; 4) tick-borne transmission of Bartonella species; or 5) simultaneous Lyme disease and Bartonella infection.

CONCLUSIONS

The medical literature does not support the diagnosis of chronic, atypical tick-borne coinfections in patients with chronic, nonspecific illnesses.

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is an illness characterized by disabling fatigue of at least 6 months. The aetiology of the condition has been hotly debated. In this chapter the evidence for CFS as a post viral condition and/or a neurological condition is reviewed. Although there is evidence that CFS is triggered by certain viruses in some patients and that neurobiological changes such as hypocortisolism are associated with the syndrome, neither mechanism is sufficient to explain the extent of the symptoms or disability experienced by patients. It is unlikely that CFS can be understood through one aetiological mechanisms. Rather it is a complex illness which is best explained in terms of a multifactorial cognitive behavioural model. This model proposes that CFS is precipitated by life events and/or viral illness in vulnerable individuals, such as those who are genetically predisposed, prone to distress, high achievement, and over or under activity. A self perpetuating cycle where physiological changes, illness beliefs, reduced and inconsistent activity, sleep disturbance, medical uncertainty and lack of guidance interact to maintain symptoms. Treatments based on this model including cognitive behavioural therapy and graded exercise therapy are effective at significantly reducing fatigue and disability in CFS. This chapter provides a description of these approaches and details of the trials conducted in the area.

The common immunogenic etiology of chronic fatigue syndrome: from infections to vaccines via adjuvants to the ASIA syndrome

Chronic fatigue syndrome (CFS) is characterized by unexplained fatigue that lasts for at least 6 months with a constellation of other symptoms. Most cases start suddenly, and are usually accompanied by a flu-like illness. It is a symptom-based diagnosis of exclusion, the pathogenesis of which is unknown. Studies have examined and hypothesized about the possible biomedical and epidemiologic characteristics of the disease, including genetic predisposition, infections, endocrine abnormalities, and immune dysfunction and psychological and psychosocial factors. Recently, the AISA (autoimmune/inflammatory syndrome induced by adjuvants) syndrome was recognized, indicating the possible contribution of adjuvants and vaccines to the development of autoimmunity.

Psychopathology and physical activity as predictors of chronic fatigue syndrome in the 1958 british birth cohort: a replication study of the 1946 and 1970 birth cohorts

Purpose

In this study, we investigate whether prospective associations between psychopathology, physical activity, and chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) observed in the 1946 and 1970 birth cohorts were replicable in the 1958 British birth cohort.

Methods

Prospective study using the 1958 British birth cohort, which included 98.7% of births from 1 week in March 1958 in England, Wales, and Scotland. The outcome was self-reported CFS/ME by the age of 42 years, at which point 11,419 participants remained in the study. Psychopathology was assessed by the Rutter scales in childhood and the Malaise Inventory in adulthood. Physical activity was reported by the cohort member, mother and teacher in childhood and adulthood.

Results

The prevalence of CFS/ME was 1.0% (95% confidence interval [CI] = 0.9–1.3) and the median age of onset was 34 years. Premorbid psychopathology at 23 years (odds ratio [OR] = 1.85, 95% CI = 1.06–3.22) and 33 years (OR = 2.81, 95% CI = 1.28–6.18) significantly increased the odds of developing CFS/ME, supporting the 1946 cohort findings. Childhood psychopathology, sedentary behavior in childhood, and persistent exercise in adulthood were not associated with CFS/ME.

Conclusions

In cohort studies premorbid psychopathology in adulthood is a replicated risk marker for CFS/ME, whereas premorbid extremes of physical activity are not.

Postinfectious fatigue in adolescents and physical activity

OBJECTIVE

To compare adolescents who do and do not recover from acute infectious mononucleosis in terms of fatigue severity and activity levels before, during, and in the 2 years following infection.

DESIGN

Prospective case-control study.

SETTING

The baseline and 12- and 24-month evaluations occurred in the subjects' homes. The 6-month outpatient visit occurred at Children's Memorial Hospital in Chicago, Illinois.

PARTICIPANTS

Three hundred one adolescents (aged 12-18 years) with acute infectious mononucleosis.

MAIN EXPOSURES

All participants were evaluated at baseline (during active infection). Six months following infection, 39 of them met criteria for chronic fatigue syndrome. These subjects were matched by sex and Tanner stage to 39 randomly selected screened-negative subjects. Both groups were reevaluated at 12- and 24-month follow-ups.

OUTCOME MEASURES

Scores from the Fatigue Severity Scale and the Modifiable Activity Questionnaire.

RESULTS

For both groups, physical activity levels declined and sleep increased as a result of having mononucleosis. Compared with their matched controls, adolescents with chronic fatigue syndrome reported significantly higher levels of fatigue at all points and spent significantly more time sleeping during the day 6 and 12 months following infection. The 2 groups did not differ significantly in terms of physical activity levels before, during, or after infection. There was a consistent trend for decreased physical activity in the chronic fatigue syndrome group.

CONCLUSIONS

Adolescents with chronic fatigue syndrome appear to be pushing themselves in an attempt to maintain similar activity levels as their peers, but paying for it in terms of fatigue severity and an increased need for sleep, particularly during the day.

Neuropsychological functioning, illness perception, mood and quality of life in chronic fatigue syndrome, autoimmune thyroid disease and healthy participants

BACKGROUND

This study attempted to longitudinally investigate neuropsychological function, illness representations, self-esteem, mood and quality of life (QoL) in individuals with chronic fatigue syndrome (CFS) and compared them with both healthy participants and a clinical comparison group of individuals with autoimmune thyroid disease (AITD).

METHOD

Neuropsychological evaluation was administered at two time points, five weeks apart. Twenty-one individuals with CFS, 20 individuals with AITD and 21 healthy participants were matched for age, pre-morbid intelligence, education level and socio-economic status (SES). All groups also completed measures of illness perceptions, mood, self-esteem and QoL at both time points.

RESULTS

The CFS group showed significantly greater impairment on measures of immediate and delayed memory, attention and visuo-constructional ability, and reported significantly higher levels of anxiety and depression. After controlling for the effects of mood, the CFS group still demonstrated significant impairment in attention. The CFS group also reported significantly lower self-reported QoL than the AITD and healthy participants. In terms of illness perceptions, the AITD group believed that their condition would last longer, that they had more treatment control over their condition, and reported less concern than the CFS group.

CONCLUSIONS

These results suggest that the primary cognitive impairment in CFS is attention and that this is not secondary to affective status. The lower treatment control perceptions and greater illness concerns that CFS patients report may be causally related to their affective status.

Risk factors for persistent fatigue with significant school absence in children and adolescents

OBJECTIVE

To assess children and adolescents with severe fatigue who are referred to pediatricians and to examine whether factors can be identified at their first visit that predict worse outcomes at 1 year.

METHODS

Ninety-one patients, aged 8 to 18 years completed questionnaires about sleep, somatic symptoms, physical activity, and fatigue. They were reassessed 12 months later. Measurements at baseline and outcome were analyzed by using univariable logistic regression with persistent, severe fatigue (yes/no) and persistent school absence (yes/no) as dependent variables and baseline scores as independent variables.

RESULTS

After 12 months, 50.6% of the children and adolescents showed improvement; 29.1% had persistent fatigue, and 20.3% had persistent fatigue with significant school absence. Factors associated with the poorest outcome were sleep problems (odds ratio [OR]: 1.4 [95% confidence interval (CI): 1.1-1.8]), initial fatigue score (OR: 1.1 [95% CI: 1.0-1.2]), somatic complaints such as hot and cold spells (OR: 1.9 [95% CI: 1.2-3.0]), blurred vision (OR: 2.1 [95% CI: 1.1-4.0]), pain in arms and legs (OR: 2.0 [95% CI: 1.0-3.2]), back pain (OR: 1.8 [95% CI: 1.0-3.2]), constipation (OR: 1.7 [95% CI: 1.0-2.7]), and memory deficits (OR: 1.8 [95% CI: 1.0-3.2]). Resolved fatigue was associated with male gender (OR: 5.0 [95% CI: 1.6-15.5]) and a physically active lifestyle (OR: 1.3 [95% CI: 1.1-1.5]).

CONCLUSIONS

Assessment of predictive factors at the first visit enables the pediatrician to identify those patients with severe fatigue who are at risk of a poor outcome. Female gender, poor sleep quality, physically inactive lifestyle, and specific somatic complaints were important predictive factors.

Modulation of antigen-induced chronic fatigue in mouse model of water immersion stress by naringin, a polyphenolic antioxidant

It is believed that physical stress, infection and oxidative stress are involved in the development of chronic fatigue syndrome. There is little evidence stating the beneficial role of nutritional supplements in chronic fatigue syndrome. Based on this, this study was designed to evaluate the effect of naringin, a natural polyphenol, in a mouse model of immunologically-induced fatigue, wherein purified lipopolysaccharide (LPS) as well as Brucella abortus (BA) antigen was used as immunogens. The assessment of chronic fatigue syndrome was based on chronic water-immersion stress test for 10 mins as well as measurement of hyperalgesia for 19 days. Immobility time and tail withdrawal latency as well as oxidative stress were taken as the markers of fatigue. Mice challenged with LPS or BA for 19 days showed significant increase in the immobility time, hyperalgesia and oxidative stress on 19th day. Serum tumor necrosis factor-alpha (TNF-alpha) levels markedly increased with LPS or BA challenge. Concurrent treatment with naringin resulted in the significant decrease in the immobility time as well as hyperalgesia. There was significant attenuation of oxidative stress as well as in TNF-alpha levels. Present findings strongly suggest the role of oxidative stress and immunological activation in the pathophysiology of chronic fatigue syndrome, and treatment with naringin can be a valuable option in chronic fatigue syndrome.

Immunological aspects of chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a specific clinical condition that characterises unexplained disabling fatigue and a combination of non-specific accompanying symptoms for at least 6 months, in the absence of a medical diagnosis that would otherwise explain the clinical presentation. Other common symptoms include headaches, myalgia, arthralgia, and post-exertional malaise; cognitive difficulties, with impaired memory and concentration; unrefreshing sleep; and mood changes. Similar disorders have been described for at least two centuries and have been differently named neurasthenia, post-viral fatigue, myalgic encephalomyelitis and chronic mononucleosis. Recent longitudinal studies suggest that some people affected by chronic fatigue syndrome improve with time but that most remain functionally impaired for several years. The estimated worldwide prevalence of CFS is 0.4-1% and it affects over 800,000 people in the United States and approximately 240,000 patients in the UK. No physical examination signs are specific to CFS and no diagnostic tests identify this syndrome. The pathophysiological mechanism of CFS is unclear. The main hypotheses include altered central nervous system functioning resulting from an abnormal immune response against a common antigen; a neuroendocrine disturbance; cognitive impairment caused by response to infection or other stimuli in sentient people. The current concept is that CFS pathogenesis is a multifactorial condition. Various studies have sought evidence for a disturbance in immunity in people with CFS. An alteration in cytokine profile, a decreased function of natural killer (NK) cells, a presence of autoantibodies and a reduced responses of T cells to mitogens and other specific antigens have been reported. The observed high level of pro-inflammatory cytokines may explain some of the manifestations such as fatigue and flu-like symptoms and influence NK activity. Abnormal activation of the T lymphocyte subsets and a decrease in antibody-dependent cell-mediated cytotoxicity have been described. An increased number of CD8+ cytotoxic T lymphocytes and CD38 and HLA-DR activation markers have been reported, and a decrease in CD11b expression associated with an increased expression of CD28+ T subsets has been observed. This review discusses the immunological aspects of CFS and offers an immunological hypothesis for the disease processes.

Curcumin, a polyphenolic antioxidant, attenuates chronic fatigue syndrome in murine water immersion stress model

Chronic fatigue syndrome, infection and oxidative stress are interrelated in epidemiological case studies. However, data demonstrating scientific validation of epidemiological claims regarding effectiveness of nutritional supplements for chronic fatigue syndrome are lacking. This study is designed to evaluate the effect of natural polyphenol, curcumin, in a mouse model of immunologically induced fatigue, where purified lipopolysaccharide (LPS) and Brucella abortus (BA) antigens were used as immunogens. The assessment of chronic fatigue syndrome was based on chronic water-immersion stress test for 10 min daily for 19 days and the immobility time was taken as the marker of fatigue. Mice challenged with LPS or BA for 19 days showed significant increase in the immobility time and hyperalgesia on day 19, as well as marked increase in serum tumor necrosis factor-alpha (TNF-alpha) levels. Concurrent treatment with curcumin resulted in significantly decreased immobility time as well as hyperalgesia. There was significant attenuation of oxidative stress as well as TNF-alpha levels. These findings strongly suggest that during immunological activation, there is significant increase in oxidative stress and curcumin can be a valuable option in the treatment of chronic fatigue syndrome.

Gene expression subtypes in patients with chronic fatigue syndrome/myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a multisystem disease, the pathogenesis of which remains undetermined. We set out to determine the precise abnormalities of gene expression in the blood of patients with CFS/ME. We analyzed gene expression in peripheral blood from 25 patients with CFS/ME diagnosed according to the Centers for Disease Control and Prevention diagnostic criteria and 50 healthy blood donors, using a microarray with a cutoff fold difference of expression of >or=2.5. Genes showing differential expression were further analyzed in 55 patients with CFS/ME and 75 healthy blood donors, using quantitative polymerase chain reaction. Differential expression was confirmed for 88 genes; 85 were upregulated, and 3 were downregulated. Highly represented functions were hematological disease and function, immunological disease and function, cancer, cell death, immune response, and infection. Clustering of quantitative polymerase chain reaction data from patients with CFS/ME revealed 7 subtypes with distinct differences in Medical Outcomes Survey Short Form-36 scores, clinical phenotypes, and severity.

Effectiveness of personal protective measures to prevent Lyme disease

Use of protective clothing and tick repellents on the skin or clothing while outdoors is 40% and 20% effective, respectively.

After the manufacture of Lyme vaccine was discontinued in 2002, strategies to prevent Lyme disease (LD) have focused on personal protective measures. Effectiveness of these measures has not been conclusively demonstrated. The aim of our case–control study was to assess the effectiveness of personal preventive measures in a highly disease-endemic area. Case-patients were persons with LD reported to Connecticut’s Department of Public Health and classified as having definite, possible, or unlikely LD. Age-matched controls without LD were identified. Study participants were interviewed to assess the practice of preventive measures and to obtain information on occupational and recreational risk factors. Use of protective clothing was 40% effective; routine use of tick repellents on skin or clothing was 20% effective. Checking one’s body for ticks and spraying property with acaricides were not effective. We concluded that use of protective clothing and of tick repellents (on skin or clothing) are effective in preventing LD.

Hematologic and urinary excretion anomalies in patients with chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) have a broad and variable spectrum of signs and symptoms with variable onsets. This report outlines the results of a single-blind, cross-sectional research project that extensively investigated a large cohort of 100 CFS patients and 82 non fatigued control subjects with the aim of performing a case-control evaluation of alterations in standard blood parameters and urinary amino and organic acid excretion profiles. Blood biochemistry and full blood counts were unremarkable and fell within normal laboratory ranges. However, the case-control comparison of the blood cell data revealed that CFS patients had a significant decrease in red cell distribution width and increases in mean platelet volume, neutrophil counts, and the neutrophil-lymphocyte ratio. Evaluation of the urine excretion parameters also revealed a number of anomalies. The overnight urine output and rate of amino acid excretion were both reduced in the CFS group (P < 0.01). Significant decreases in the urinary excretion of asparagine (P < 0.0001), phenylalanine (P < 0.003), the branch chain amino acids (P < 0.005), and succinic acid (P < 0.0001), as well as increases in 3-methylhistidine (P < 0.05) and tyrosine (P < 0.05) were observed. It was concluded that the urinary excretion and blood parameters data supported the hypothesis that alterations in physiologic homeostasis exist in CFS patients.

Infection and vaccination in chronic fatigue syndrome: myth or reality?

Chronic fatigue syndrome (CFS) is characterized by severe disabling fatigue lasting for more than 6 months associated with physical and mental disturbances such as headache, arthralgia, myalgia, memory impairment, sore throat and tender lymph nodes. The exact pathogenesis is still unknown. Several models were proposed to explain its etiology including chronic infection, endocrine dysfunction, autonomic imbalance, depression, decreased immunity states and an aberrant reaction to infection. No convincing evidence was found to support any of the suggested pathogenic mechanisms. The current concept is that CFS pathogenesis is a multi factorial condition in which an infective agent cause an aberrant immune response characterized by a shift to Th-2 dominant response. When the response fails to be switched-off, a chronic immune activation occurs and clinically expressed as the symptomatology of CFS. Vaccinations are used in order to stimulate the immune system to induce a persistent immunity against the favorable antigens. Several syndromes that contain chronic fatigue as one of their symptoms, such as "Gulf war syndrome" and macrophagic myofasciitis were related to vaccinations. Can vaccinations induce the aberrant immune response of CFS? Little is known about this issue. There are some reports on CFS occurring after vaccination, but few prospective and retrospective studies failed to find such an association. A working group of the Canadian Laboratory Center for Disease Control (LCDC) that was founded in order to examine the suspected association between CFS and vaccinations concluded that there is no evidence that relates CFS to vaccination. Further studies are requested to examine this issue since it is very conceivable that if infection can lead to CFS, vaccination may also lead to it in the same immune-mediated pathogenesis.

A case control study of premorbid and currently reported physical activity levels in chronic fatigue syndrome

BACKGROUND

Patients with chronic fatigue syndrome typically report high levels of physical activity before becoming ill. Few studies have examined premorbid and current activity levels in chronically fatigued patients.

METHODS

In a case-control study, 33 patients with chronic, unexplained, disabling fatigue attending a university-based clinic specializing in fatigue were compared to 33 healthy, age- and sex-matched controls. Patients rated their activity levels before their illness and currently, using scales designed for this purpose. Controls reported their level of activity of 2 years previously and currently. Chi-square analyses, Student's t tests, and Wilcoxon signed rank tests were used in pair matched analyses.

RESULTS

Compared to healthy controls, patients with chronic, unexplained fatigue rated themselves as more active before their illness (p < or = 0.001) and less active currently (p < or = 0.001). The patients also reported they currently stood or walked less than the controls (median [inter-quartile range] = 4 2345 versus 9 [7.5-12] hours, p < or = 0.001), and spent more time reclining (median [inter-quartile range] = 12 10111213141516 versus 8 [8-9.5] hours, p < or = 0.001). These differences remained significant for the subset of patients who met strict criteria for chronic fatigue syndrome or fibromyalgia.

CONCLUSION

Patients with chronic, unexplained, disabling fatigue reported being more active before becoming ill than healthy controls. This finding could be explained by greater premorbid activity levels that could predispose to illness, or by an overestimation of previous activity. Either possibility could influence patients' perceptions of their current activity levels and their judgments of recovery. Perceived activity should be addressed as part of management of the illness.

Chronic fatigue syndrome: an update focusing on phenomenology and pathophysiology

PURPOSE OF REVIEW

Chronic fatigue syndrome is a controversial condition especially concerning its clinical definition and aetiopathogenesis. Most recent research progress has been made in phenomenology and pathophysiology and we focused our review on these two areas.

RECENT FINDINGS

The phenomenology research supports the notion of a discrete fatigue syndrome which can be distinguished from depression and anxiety. The current case definition, however, may need an improvement based on empirical data. Recent advances in understanding the pathophysiology of chronic fatigue syndrome continue to demonstrate the involvement of the central nervous system. Hyperserotonergic state and hypoactivity of the hypothalamic-pituitary-adrenal axis constitute other findings, but the question of whether these alterations are a cause or consequence of chronic fatigue syndrome still remains unanswered. Immune system involvement in the pathogenesis seems certain but the findings on the specific mechanisms are still inconsistent. Genetic studies provide some evidence of the syndrome being a partly genetic condition, but environmental effects seem to be still predominant and identification of specific genes is still at a very early stage.

SUMMARY

The recent findings suggest that further research is needed in improving the current case definition; investigating overlaps and boundaries among various functional somatic syndromes; answering the question of whether the pathophysiologic findings are a cause or consequence; and elucidating the involvement of the central nervous system, immune system and genetic factors.

Time course of exercise induced alterations in daily activity in chronic fatigue syndrome

In a previous study we demonstrated that while people with CFS had lower daily activity levels than control subjects, they were able to increase daily activity via a daily walking program. We reanalyzed our data to determine the time course of activity changes during the walking program. Daily activity assessed via an accelometer worn at the hip was divided into sleep, active, and walking periods. Over the first 4–10 days of walking the subjects with CFS were able to reach the prescribed activity goals each day. After this time, walking and total activity counts decreased. Sedentary controls subjects were able to maintain their daily walking and total activity goals throughout the 4 weeks. Unlike our previous interpretation of the data, we feel this new analysis suggests that CFS patients may develop exercise intolerance as demonstrated by reduced total activity after 4–10 days. The inability to sustain target activity levels, associated with pronounced worsening of symptomology, suggests the subjects with CFS had reached their activity limit.

Gene expression in peripheral blood mononuclear cells from patients with chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is a multisystem disease, the pathogenesis of which remains undetermined.

AIMS

To test the hypothesis that there are reproducible abnormalities of gene expression in patients with CFS compared with normal healthy persons.

METHODS

To gain further insight into the pathogenesis of this disease, gene expression was analysed in peripheral blood mononuclear cells from 25 patients with CFS diagnosed according to the Centers for Disease Control criteria and 25 normal blood donors matched for age, sex, and geographical location, using a single colour microarray representing 9522 human genes. After normalisation, average difference values for each gene were compared between test and control groups using a cutoff fold difference of expression > or = 1.5 and a p value of 0.001. Genes showing differential expression were further analysed using Taqman real time polymerase chain reaction (PCR) in fresh samples.

RESULTS

Analysis of microarray data revealed differential expression of 35 genes. Real time PCR confirmed differential expression in the same direction as array results for 16 of these genes, 15 of which were upregulated (ABCD4, PRKCL1, MRPL23, CD2BP2, GSN, NTE, POLR2G, PEX16, EIF2B4, EIF4G1, ANAPC11, PDCD2, KHSRP, BRMS1, and GABARAPL1) and one of which was downregulated (IL-10RA). This profile suggests T cell activation and perturbation of neuronal and mitochondrial function. Upregulation of neuropathy target esterase and eukaryotic translation initiation factor 4G1 may suggest links with organophosphate exposure and virus infection, respectively.

CONCLUSION

These results suggest that patients with CFS have reproducible alterations in gene regulation.

Cytokine production and modulation: comparison of patients with chronic fatigue syndrome and normal controls

We studied cytokine production in 15 patients with chronic fatigue syndrome (CFS) and 23 controls. CFS patients' peripheral blood mononuclear cells were cultured with lipopolysaccharide or phytohemagglutinin. Enzymatic immunoassay indicated cytokine concentration in culture supernatants. CFS patients showed significantly lower mRNA levels and transforming growth factor-beta1 (TGF-beta1) production. Cytokine dysregulation affects CFS pathogenesis. TGF-beta1 may aid treatment because it affects CFS inflammatory characteristics.

Childhood predictors of self reported chronic fatigue syndrome/myalgic encephalomyelitis in adults: national birth cohort study

OBJECTIVE

To study childhood risk factors for chronic fatigue syndrome in adult life.

DESIGN

Examination of data from the 1970 British birth cohort.

PARTICIPANTS

16,567 babies born 5-11 April 1970, followed up at 5, 10, 16, and 29-30 years.

MAIN OUTCOME MEASURES

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) identified by self report at age 30 years. Data from childhood from questionnaires given to parents and teachers. Maternal mental health assessed with the malaise inventory.

RESULTS

93 (0.8%, 95% confidence interval 0.7 to 1.0) of 11 261 participants reported ever having CFS/ME, and 48 (0.4%, 0.3 to 0.6) had the condition currently. Higher risk of CFS/ME was associated with having a limiting longstanding condition in childhood (odds ratio 2.3, 1.4 to 3.9), female sex (2.3, 1.4 to 2.6), and high social class in childhood (2.2, 1.4 to 3.5). Higher levels of exercise in childhood were associated with lower risk (0.5, 0.2 to 0.9). Maternal psychological disorder, psychological problems in childhood, birth weight, birth order, atopy, obesity, school absence, academic ability, and parental illness were not associated with risk of CFS/ME.

CONCLUSIONS

We identified no association between maternal or child psychological distress, academic ability, parental illness, atopy, or birth order and increasing risk of lifetime CFS/ME. Sedentary behaviour increased the risk.

Fatigue and aging

Fatigue is the most common chronic symptom of cancer and the symptom most likely to disrupt the patient's activity and to cause disability.Fatigue affects older cancer patients to the same order of magnitude as younger ones and appears to be related to different factors such as anemia, depression, and reduced neuromuscular energy production. Interestingly, some studies have suggested that the duration of fatigue may be age-related. In the elderly, fatigue may cause functional dependence; functional dependence may lead to interruption of treatment, decline in quality of life and expensive home care. Available interventions include reduction of centrally acting drugs, management of anemia and metabolic abnormalities, and management of depression, treatment of sleep disorders, correction of endocrine abnormalities and realistic exercise programmes.

Aluminum inclusion macrophagic myofasciitis: a recently identified condition

The authors conclude that the persistence of aluminum hydroxide at the site of intramuscular injection is a novel finding which has an exact significance that remains to be established fully. It seems mandatory to evaluate possible long-term adverse effects induced by this compound, because this issue has not been addressed (in the past, aluminum hydroxide was believed to be cleared quickly from the body). If safety concerns about the long-term effects of aluminum hydroxide are confirmed, novel and alternative vaccine adjuvants to rescue vaccine-based strategies should be proposed to ensure the enormous benefit for public health that these vaccines provide worldwide.

Cytokines in parvovirus B19 infection as an aid to understanding chronic fatigue syndrome

Human parvovirus B19 infection has been associated with various clinical manifestations of a rheumatic nature such as arthritis, fatigue, and chronic fatigue syndrome (CFS), which can persist for years after the acute phase. The authors have demonstrated recently that acute B19 infection is accompanied by raised circulating levels of IL-1b, IL-6, TNF-a, and IFN-g and that raised circulating levels of TNF-a and IFN-g persist and are accompanied by MCP-1 in those patients who develop CFS. A resolution of clinical symptoms and cytokine dysregulation after intravenous immunoglobulin (IVIG) therapy, which is the only specific treatment for parvovirus B19 infection, also has been reported. Although CFS may be caused by various microbial and other triggers, that triggered by B19 virus is clinically indistinguishable from idiopathic CFS and exhibits similar cytokine abnormalities and may represent an accessible model for the study of CFS.

A systematic review and critical evaluation of the immunology of chronic fatigue syndrome

OBJECTIVE

Immune dysfunction in patients with chronic fatigue syndrome (CFS) has been widely but inconsistently reported. Traditional reviews of the literature have produced a variety of conclusions. We present the results of the first systematic review of the subject.

METHODS

EMBASE, MEDLINE and PSYCHINFO databases were searched, and leading researchers in the field were contacted. Inclusion criteria were applied, and studies were then divided into groups based on the quality of their methodology. Study results were collated and described.

RESULTS

Studies ranged widely in quality. There was an inverse association between study quality and finding low levels of natural killer cells, suggesting that the association may be related to study methodology. On the other hand, reports of abnormalities in T cells and cytokine levels were not related to study quality.

CONCLUSIONS

The conclusions of this systematic review differ from a recent traditional narrative review of the immunology of CFS. No consistent pattern of immunological abnormalities is identified.

Long-term neuropsychologic and health outcomes of children with facial nerve palsy attributable to Lyme disease

BACKGROUND

There is little information about the long-term outcomes of children with facial nerve palsy attributable to Lyme disease, a group putatively at high risk for poor neurologic outcomes.

OBJECTIVE

The purpose of this study is to assess the long-term neuropsychologic and health outcomes of children with facial nerve palsy attributable to Lyme disease.

METHODS

We conducted a matched cross-sectional study of children with facial nerve palsy in Connecticut who met the Centers for Disease Control and Prevention national surveillance case definition for Lyme disease. We identified children with facial nerve palsy attributable to Lyme disease from population-based data for the state of Connecticut from 1984 to 1991 as well as from selected clinical practices from 1984 to 1998. For each case, 2 controls without Lyme disease, matched by age, were selected by sequential digit dialing technique. Both patients and controls (or their parents) were interviewed using structured questionnaires. Outcomes included self/parents' reports both of symptoms and of abilities to perform normal daily activities since the diagnosis was made (or for an equivalent period of time for controls). In addition, the patients with facial nerve palsy attributable to Lyme disease were evaluated with a battery of neuropsychologic tests.

RESULTS

Of the 43 patients, 30% were female and 93% were white. Median age at diagnosis was 8 years (range: 2-18 years). Mean time to follow-up was 49 months (range: 7-161 months). Of the patients, 16% had been treated parenterally with ceftriaxone and 84% had been treated orally with either doxycycline or amoxicillin. Overall, 79% believed they were cured of Lyme disease, 9% believed they were not cured, and 12% did not know. The proportions of patients and of matched controls that reported increased problems with normal daily activities (eg, exercise, academic performance, word recall, sleeping) were similar. Patients with facial nerve palsy attributable to Lyme disease were more likely than matched controls to report symptoms of neck pain, changes in behavior, pains in joints or muscles, numbness or funny sensations in nerves, and problems with memory, but three quarters of them did not attribute these problems to Lyme disease. Twenty patients agreed to undergo neuropsychologic testing; all had average to above average scores on tests of IQ (eg, mean IQ was 110.2), memory, learning, attention, concentration, math, reading and spelling performance, executive functioning, abstract thinking, sequential processing, visuospatial scanning, and motor speed. There were no apparent differences in outcomes between children who received oral versus parenteral treatment.

CONCLUSIONS

The neuropsychologic and health outcomes of children with facial nerve palsy attributable to Lyme disease 7 to 161 months earlier are comparable to those who did not have Lyme disease.

Successful intravenous immunoglobulin therapy in 3 cases of parvovirus B19-associated chronic fatigue syndrome

Three cases of chronic fatigue syndrome (CFS) that followed acute parvovirus B19 infection were treated with a 5-day course of intravenous immunoglobulin (IVIG; 400 mg/kg per day), the only specific treatment for parvovirus B19 infection. We examined the influence of IVIG treatment on the production of cytokines and chemokines in individuals with CFS due to parvovirus B19. IVIG therapy led to clearance of parvovirus B19 viremia, resolution of symptoms, and improvement in physical and functional ability in all patients, as well as resolution of cytokine dysregulation.

Joint hypermobility is more common in children with chronic fatigue syndrome than in healthy controls

OBJECTIVE

To determine whether children with chronic fatigue syndrome (CFS) have a higher prevalence of joint hypermobility than gender-matched controls.

STUDY DESIGN

Matched case-control study comparing the Beighton joint hypermobility scores in 58 consecutive children with CFS (incident cases) with 58 otherwise healthy controls referred to a dermatology clinic for evaluation of common skin problems. A second group of 58 patients previously diagnosed with CFS (prevalent cases) was matched by gender to the incident cases to evaluate temporal changes in referral patterns.

RESULTS

Of the 58 patients in each group, 71% were female. The median Beighton scores were higher in incident CFS cases than in healthy controls (4 vs 1, P <.001). More incident CFS cases had Beighton scores >/=4 (consistent with joint hypermobility), 60% versus 24%, P <.0001. Incident and prevalent CFS cases had similar Beighton scores. The odds ratio for hypermobility in all patients with CFS versus healthy controls was 3.5 (P <.001; 95% CI, 1.6-7.5).

CONCLUSIONS

Joint hypermobility is more common in patients with CFS than in otherwise healthy children with common skin disorders. The etiologic significance of the observed association remains to be defined.

Do silicone breast implants cause rheumatologic disorders? A systematic review for a court-appointed national science panel

OBJECTIVE

To assist in evaluating expert testimony and scientific evidence presented in law suits brought against silicone breast implant manufacturers, a US District Court Order established a National Science Panel to assess whether existing studies provide scientific evidence of an association between silicone breast implants and systemic classic/accepted connective disease, atypical connective disease, and certain signs and symptoms identified by plaintiffs in the law suits. Local disorders potentially associated with these implants were not addressed in this review. Therefore, we performed a systematic review of published studies on the association between silicone breast implants and systemic connective tissue disorders.

METHODS

Data from relevant studies (human cohort, case-control, or cross-sectional studies with > or = 10 participants and appropriate controls) were identified through literature searches of Medline, Current Contents, HealthStar, Biological Abstracts, EMBase, Toxline, and Dissertation Abstracts. Two independent reviewers, using standard collection forms, extracted data from the included studies. Adjusted relative risks (RRs) in cohort studies and odds ratios (ORs) in case-control and cross-sectional studies were reported if provided; otherwise, unadjusted RRs and ORs were calculated.

RESULTS

Twenty-four studies meeting inclusion criteria were identified. No association was evident between breast implants and any established or atypical connective tissue disorder. There was discordance among studies in reports of arthralgias, lymphadenopathy, myalgias, sicca symptoms, skin changes, and stiffness.

CONCLUSION

The panel found no evidence to support expert testimony suggesting an association between silicone breast implants and connective diseases. Discordance for symptoms may reflect differences in symptoms included in various categories, the small number of cases, and the effect of having single subjects with > 1 symptom represented in analyses of each symptom reported. The process presented here is an early example of the use of independent scientific panels to help courts clarify scientific evidence in legal proceedings.

Cytokines play an aetiopathogenetic role in fibromyalgia: a hypothesis and pilot study

OBJECTIVE

To measure soluble factors having a possible role in fibromyalgia (FM) and compare the profiles of patients with recent onset of the syndrome with patients with chronic FM.

METHODS

The production of cytokines, cytokine-related molecules, and a CXC chemokine, interleukin (IL)-8, was examined. Fifty-six patients with FM (23 with <2 yr and 33 with >2 yr of symptoms) were compared with age- and sex-matched healthy controls. Cytokines and cytokine-related molecules were measured in sera and in supernatants of peripheral blood mononuclear cells (PBMC) that were incubated with and without lectins and phorbol myristate acetate (PMA).

RESULTS

No differences between FMS and controls were found by measuring IL-1beta, IL-2, IL-10, serum IL-2 receptor (sIL-2R), interferon gamma (IFN-gamma), and tumour necrosis factor alpha (TNF-alpha). Levels of IL-1R antibody (IL-1Ra) and IL-8 were significantly higher in sera, and IL-1Ra and IL-6 were significantly higher in stimulated and unstimulated FM PBMC compared with controls. Serum IL-6 levels were comparable to those in controls, but were elevated in supernatants of in vitro-activated PBMC derived from patients with >2 yr of symptoms. In the presence of PMA, there were additional increases in IL-1Ra, IL-8 and IL-6 over control values.

CONCLUSIONS

In patients with FM we found increases over time in serum levels and/or PBMC-stimulated activity of soluble factors whose release is stimulated by substance P. Because IL-8 promotes sympathetic pain and IL-6 induces hyperalgesia, fatigue and depression, it is hypothesized that they may play a role in modulating FM symptoms.

Associations between perfectionism, mood, and fatigue in chronic fatigue syndrome: a pilot study

This study investigated possible associations between perfectionistic personality traits, mood, and fatigue in chronic fatigue syndrome (CFS). Forty CFS sufferers referred to tertiary care and 31 control healthy subjects completed the Multidimensional Perfectionism Scale (MPS), Chalder Fatigue Questionnaire, and Hospital Anxiety and Depression (HAD) scale. Total perfectionism scores did not correlate with fatigue, anxiety, or depression in either group. Other-oriented MPS scores were significantly lower among CFS sufferers (p = .0019), especially women, and correlated negatively with physical fatigue levels overall (R = -0.27, p = .02). Total and socially prescribed MPS scores correlated with age for the CFS group alone (p = .05). Possible reasons why this study did not confirm a positive association between perfectionism and CFS are discussed. The finding that CFS sufferers set lower standards and have lower expectations for significant others may have implications for rehabilitation and recovery from this disorder.

Orthostatic intolerance in the chronic fatigue syndrome

This study aims to investigate the prevalence and pathophysiology of orthostatic intolerance (OI) and its potential contribution to symptoms of a group of unselected patients with chronic fatigue syndrome (CFS). Seventy five patients (65 women, 10 men) with CFS were evaluated. During an initial visit, a clinical suspicion as to the likelihood of observing laboratory evidence of OI was assigned. Laboratory investigation consisted of beat-to-beat recordings of heart rate, blood pressure (Finapres), and stroke volume (impedance cardiograph) while supine and during 80 degrees head-up tilt (HUT), during rhythmic deep breathing (6 breaths/min) and during the Valsalva maneuver. The responses of 48 age-matched healthy controls who had no history of OI were used to define the range of normal responses to these three maneuvers. Forty percent of patients with CFS had OI during head-up tilt. Sixteen exhibited neurally-mediated syncope alone, seven tachycardia (> 35 bpm averaged over the whole of the head-up tilt) and six a mixture of tachycardia and syncope. Eight of 48 controls exhibited neurally-mediated syncope. The responses to the Valsalva maneuver and to deep breathing were similar in controls and patients. On average, the duration of disease and patient age were significantly less and the onset of symptoms was more often subacute in patients with OI than in those without OI. We conclude that there exists a clinically identifiable subgroup of patients with CFS and OI that differs from control subjects and from those with CFS without OI for whom treatment specifically aimed at improving orthostatic tolerance may be indicated.

The importance of orthostatic intolerance in the chronic fatigue syndrome

Chronic fatigue syndrome (CFS) or myalgic encephalomyelitis is a clinically defined syndrome characterized by persistent or relapsing debilitating fatigue for longer than 6 months in the absence of any definable medical diagnosis. The cause of this syndrome is unknown. Symptoms of orthostatic intolerance, such as disabling fatigue, dizziness, diminished concentration, tremulousness, and nausea, are often found in patients with CFS. In this review, we critically evaluate the relationship between orthostatic intolerance and CFS. Particular emphasis is placed on clinical diagnosis, laboratory testing, pathophysiology, and therapeutic management. It is hoped that this review will provide a stimulus for further study of this complex and disabling condition.