Enteroviral RNA sequences detected by polymerase chain reaction in muscle of patients with postviral fatigue syndrome

Immunoglobulin subclass levels in chronic fatigue syndrome

The levels of immunoglobulin subclasses were determined for 46 patients meeting the original Centers for Disease Control case definition of chronic fatigue syndrome and were compared to values obtained for 50 age- and gender-matched healthy volunteer blood donor controls. The levels of immunoglobulin subclasses in these groups were further compared to a third group of additional chronic fatigue syndrome cases from whom samples had been obtained and frozen prospectively over a period of 7 years. These data do not demonstrate significant immunoglobulin subclass deficiencies in patients with chronic fatigue syndrome.

Enteroviral polymerase chain reaction in the investigation of aseptic meningitis

We used a nested polymerase chain reaction (nPCR) to seek evidence for enteroviruses in clinical samples from patients with symptoms of aseptic meningitis. When compared with conventional virus isolation methods on a total of 366 samples collected during 1994-1995, an increase in positivity from 6% to 27% was shown. The results indicate that nPCR would be a valuable aid to the laboratory diagnosis of enteroviral infections as it can detect those enteroviruses that cannot be identified by current isolation methods.

Evidence of presence of poliovirus genomic sequences in cerebrospinal fluid from patients with postpolio syndrome

The postpolio syndrome (PPS) is characterized by new neuromuscular symptoms occurring 30 to 40 years after the acute episode of poliomyelitis paralysis. The presence of the poliovirus RNA genome in the cerebrospinal fluid from 10 patients with PPS and from 23 control patients was sought by using reverse transcription and a PCR specific for polioviruses and/or other enteroviruses. Poliovirus-specific genomic sequences in the 5' untranslated region and in the capsid region (VP1) were detected by reverse transcription PCR in 5 of 10 patients with PPS but in none of the control patients. Sequencing confirmed the presence of mutated poliovirus sequences. This finding suggests persistent viral infection in the central nervous system related to the presence of poliovirus genomes.

Search for picornaviruses at onset of inflammatory myopathy

Picornaviruses may not play a role as persistent agents in the inflammatory myopathies, but it is still thought likely that they may act as triggers of an autoimmune process. Forty one muscle biopsy specimens, taken from three weeks to six months (mean four months) after onset, were examined using three different picornaviral primers and PCR. Moderate to severe disease activity was evident in all specimens. The results were compared with those of 18 biopsy specimens examined later in the disease course, and with specimens from 27 patients with non-inflammatory myopathies. All results were negative. Thus, even as early as three weeks after clinical disease appears, picornaviruses are not detectable in these disorders.

Somatisation in children

This review summarises recent work on somatisation in childhood. Minor physiological dysfunction may play a part in a number of cases and associated psychiatric disorders are commonly though not universally found. Contributory family factors include high rates of health problems and of parental psychological distress and there is some evidence for the role of family modelling and reinforcement of illness behaviour. There is suggestive evidence linking somatisation to emotional closeness in families, to family togetherness around health matters and to anomalies in children's social relationships. Somatisation in children can respond to treatments involving cognitive-behavioural and family techniques as well as to sensitive, psychologically sound advice from paediatricians.

No findings of enteroviruses in Swedish patients with chronic fatigue syndrome

Enteroviruses have been proposed to cause an immune complex disease in the chronic fatigue syndrome. Altogether 34 patients with the chronic fatigue syndrome, according to criteria of the Centers for Disease Control, USA, were studied evenly over the seasons for the possible presence of a chronic enterovirus infection. In 11 patients, 1-5 faecal samples were collected at about 6 month intervals for virus isolation before and after acid treatment, followed by ultracetrifugation at pH 3 to dissolve possible enterovirus-antibody complexes. Another 14 fecal samples were subjected to routine virus isolation alone. Seven pairs of serum-cerebrospinal fluid samples were analysed for cross-reactive IgG antibody activity to enteroviruses. In 29 patients a muscle biopsy was collected for enterovirus polymerase chain reaction (PCR). We were unable to identify enteroviruses in any of these samples by any of these techniques. Our study does not confirm evidence for persistent enterovirus infection in the chronic fatigue syndrome.

Search for persistent infection with poliovirus or other enteroviruses in amyotrophic lateral sclerosis-motor neurone disease

A longstanding hypothesis proposes that amyotrophic lateral sclerosis-motor neurone disease (ALS-MND) is a late consequence of subclinical poliovirus (PV) infection. In this study, RNA extracts of CNS tissue from 28 patients with ALS-MND and 7 controls were assayed by nested polymerase chain reaction (PCR) using primers to the 5'-untranslated region (UTR) of the enterovirus (EV) genome which is highly conserved between EVs including PV, echovirus and coxsackie viruses. The integrity of RNA extracted from either archival paraffin-embedded or frozen CNS tissue was assessed by detection of constitutive Ableson tyrosine kinase (ABL) mRNA by PCR. Of 63 tissue samples assayed, 81% (51/63) were ABL-positive corresponding to 78% (22/28) of the ALS-MND cases and all controls. None of the 27 ALS-MND cases (i.e. 21 ABL+ and 6 ABL-) in which paraffin-embedded tissue was used nor any of the age and sex matched controls were positive for specific PV/EV RNA. Moreover, CNS tissue from 14 different locations obtained from one patient < 2 hrs after death and immediately frozen, showed no evidence of PV/EV at any site by PCR. Disease duration, degree of tissue autolysis and duration of tissue storage were all excluded as factors which may predispose to negative results. The sensitivity of the PV PCR was determined to be 40-400 copies (12.5 - 125 ag) of synthetic EV RNA transcripts in 1 microgram of cellular RNA and the assay was shown to detect all types of PV and and other EVs tested. Thus it seems unlikely that a persistent PV or related EV infection is implicated in ALS-MND unless there has been alteration in the 5'-UTR of the virus genome.

Comparison of coxsackie B neutralisation and enteroviral PCR in chronic fatigue patients

Coxsackie B enteroviruses have been implicated repeatedly as agents associated with chronic fatigue syndrome (CFS). The objective of this study was to compare the serological evidence for the presence of Coxsackie B virus neutralising antibody, with the polymerase chain reaction (PCR) detecting a portion of the 5' nontranslated region (NTR) of the enterovirus genome. Serum samples from 100 chronic fatigue patients and from 100 healthy comparison patients were used in this study. In the CFS study group, 42% patients were positive for enteroviral sequences by PCR, compared to only 9% of the comparison group. Using the neutralisation assay, 34% of study patients were positive, compared to 41% of comparison patients. In the study group, 66/100 patient results correlated, i.e., they were either positive/positive or negative/negative for both tests. Of those that did not correlate, the majority were PCR-positive/Coxsackie B antibody-negative (21/34). In the comparison group, 58/100 patient results correlated. Of those that did not, the majority were PCR-negative/Coxsackie B antibody-positive (37/42). The Coxsackie B antibody neutralisation assay was not able to differentiate the CFS study group from the healthy comparison group, and thus the clinical relevance of this assay may be questioned. The PCR assay did differentiate the two groups with significantly more CFS patients having evidence of enterovirus than the comparison group.

Postinfectious fatigue: prospective cohort study in primary care

The idea that chronic fatigue has an infectious origin has become popular, but the main evidence for such an association has come from retrospective case-control studies, which are subject to ascertainment bias. We report a prospective study of the outcome of clinically diagnosed infections in patients presenting to UK general practitioners. Questionnaires assessing fatigue and psychiatric morbidity were sent to all patients aged 18-45 years in the study practices. The prevalence of chronic fatigue and chronic fatigue syndrome was then ascertained among 1199 people aged 18-45 who presented to the general practitioners with symptomatic infections and in 1167 people who attended the surgeries for other reasons. 84% were followed up at 6 months. 9.9% of cases and 11.7% of controls reported chronic fatigue (odds ratio 1.0 [95% CI 0.6-1.1]). There were no differences in the proportions who met various criteria for chronic fatigue syndrome. No effect of infection was noted when we excluded subjects who reported fatigue or psychological morbidity at the baseline screening. The strongest independent predictors of postinfectious fatigue were fatigue assessed before presentation with clinical infection (3.0 [1.9-4.7]) and psychological distress before presentation (1.8 [1.2-2.9]) and at presentation with the acute infection (1.8 [1.1-2.8]). There was no effect of sex or social class. Our study shows no evidence that common infective episodes in primary care are related to the onset of chronic fatigue or chronic fatigue syndrome.

Chronic fatigue syndrome: a clinical and laboratory study with a well matched control group

OBJECTIVE

To investigate the relation between severity of complaints, laboratory data and psychological parameters in patients with chronic fatigue syndrome (CFS).

SUBJECTS

Eighty-eight patients with CFS and 77 healthy controls matched for age, sex and geographical area.

METHODS

Patients and controls visited our outpatient clinic for a detailed medical history, physical examination and psychological tests: Checklist Individual Strength (CIS). Beck Depression Inventory (BDI) and Sickness Impact Profile (SIP). Venous blood was drawn for a complete blood cell count, serum chemistry panel, C-reactive protein and serological tests on a panel of infectious agents.

RESULTS

All patients fulfilled the criteria for CFS as described by Sharpe et al. (J R Soc Med 1991; 84: 118-21), only 18 patients (20.5%) fulfilled the CDC criteria. The outcome of serum chemistry tests and haematological tests were within the normal range. No significant differences were found in the outcome of serological tests. Compared to controls, significant differences were found in the results on the CIS, the BDI, and the SIP. These results varied with the number of complaints (CDC criteria). When the number of complaints was included as the covariate in the analysis, there were no significant differences on fatigue severity, depression, and functional impairment between patients who fulfilled the CDC criteria and patients who did not.

CONCLUSION

It is concluded that the psychological parameters of fatigue severity, depression and functional impairment are related to the clinical severity of the illness. Because the extensive panel of laboratory tests applied in this study did not discriminate between patients and controls, it was not possible to investigate a possible relation between the outcomes of psychological and laboratory testing.

Analysis of protein synthesis by two-dimensional gel electrophoresis in T cells persistently infected with coxsackie B virus

Coxsackie B viruses (CBV) have been implicated in various human diseases that present as either limited acute infections or prolonged chronic infections. A number of investigations have suggested that a virus-induced immune dysfunction might play a role in in vivo pathogenesis. In the current study, we describe CBV infection of two human T cell-derived cell lines (Jurkat and MOLT-4 cells) as potential models for CBV infection of lymphocytes. Short term (up to 144 h post-infection) CBV infection of either cell line resulted in a decline in the viability of the cell population together with an approximate 10-fold rise in the titre of infectious virus during the period of incubation. Analyses of the intracellular proteins by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) demonstrated that although putative virus proteins were detectable there was minimal inhibition of the cellular protein synthesis following CBV infection. This contrasted with the more permissive and highly lytic CBV infection of HEp-2C cells (Cash, Electrophoresis 1991, 10, 793-800). Persistently infected cell lines from both Jurkat and MOLT-4 cells (piJURKAT-3673 and piMOLT-2667 cells) were established. Analyses of intracellular protein synthesis of these persistently infected cell lines showed the synthesis of novel proteins not detected for the corresponding uninfected parental cell line. There were no significant alterations in overall cellular protein synthesis detectable by the small format 2-D PAGE system employed in these investigations. The data presented in the current investigation will contribute towards studies on virus-induced responses of specific biological functions associated with T cells.

Detection of enterovirus-specific RNA in serum: the relationship to chronic fatigue

The serum of 88 chronic fatigue patients was screened for enteroviral specific sequences by polymerase chain reaction (PCR) assay. The PCR method used was "nested" PCR targetting the 5' nontranslated region of the enteroviral genome which yielded a final fragment length of 264 base pairs. Samples were obtained from patients during 1990-1991. In addition, buffy coat specimens and stool specimens were examined in some patients. Samples from two cohorts of comparison individuals were also obtained. The comparison groups were firstly, acutely ill individuals with symptoms consistent with a presumed enteroviral infection (matched by age, sex, and date of receipt of specimen) and secondly, healthy individuals (matched by age and date of receipt of specimen). Enteroviral specific sequences were detected in 36 of 88 serum samples from chronic fatigue patients, 22 of 82 acutely ill individuals, and 3 of 126 healthy individuals. The enteroviral PCR positivity did not correlate with any one particular feature of chronic fatigue nor did it reflect any history of illness at onset of fatigue, duration of fatigue, or age of patient. These results provide new evidence for the presence of enteroviral specific sequences in serum, buffy coat, and stool samples in many patients with chronic fatigue. This may reflect a persistent enterovirus infection in a proportion of chronic fatigue patients.

Polymerase chain reaction and sequencing for typing rhinovirus RNA

Primers were designed and tested for their ability to distinguish rhinoviruses from enteroviruses. A primer set derived from the 5'-UTR/VP coding region junction was able to amplify all the rhinovirus serotypes tested. Enteroviruses were either not amplified by these primer pairs or produced a band of larger size that could easily be discriminated from the rhinovirus-specific product. In contrast, primers embedded in the 5'-UTR region alone were able to amplify both rhinovirus and enterovirus RNA. It is shown that rhinoviruses could be specifically typed by sequencing the amplicon derived from the 5'-UTR set. The sequences of the 5'-UTR region of ten previously unsequenced rhinoviruses were derived. The sequences obtained cluster into two groups: 1B, 41, 15, 30, 63, 31, 56, and 44; and 17, 69, and 70. Amplicons from serotypes 17,69, and 70 also group by sequence with the equivalent region of HRV14 from the genetic database, while the others group with 2 and 89.

Low frequency of detection by nested polymerase chain reaction of enterovirus ribonucleic acid in endomyocardial tissue of patients with idiopathic dilated cardiomyopathy

OBJECTIVES

The purpose of this study was to determine the prevalence of enteroviral infection in the myocardium of patients with idiopathic dilated cardiomyopathy by using a highly sensitive and specific detection technique.

BACKGROUND

Recent molecular studies have suggested that enteroviral persistence (in particular, coxsackieviruses type B) may underlie idiopathic myocarditis and dilated cardiomyopathy.

METHODS

The method used to detect enterovirus-specific ribonucleic acids (RNAs) is based on reverse transcription and nested polymerase chain reaction amplification with four pairs of primers from the conserved 5' noncoding region of the enteroviral genome. Several members of the Enterovirus genus are detectable by this assay (coxsackieviruses B1 to B6; polioviruses 1 to 3; echoviruses 9, 19 and 31), with a sensitivity threshold close to the detection of a single molecule of viral RNA in 1 mg of tissue sample. Endomyocardial tissue samples from 84 subjects were analyzed (77 samples obtained from left endomyocardial biopsies, 7 from explanted hearts). The subjects comprised 63 study patients (53 with dilated cardiomyopathy, 3 with idiopathic myocarditis, 1 with right ventricular dysplasia, 1 with restrictive cardiomyopathy, 1 with eosinophilic myocarditis, 1 with primary ventricular fibrillation and 3 with myocarditis of known etiology) and 21 control subjects with other diseases.

RESULTS

Positive signals were obtained only in samples from six study patients (four with dilated cardiomyopathy, one with right ventricular dysplasia and one with myocarditis). Samples from control subjects, uninfected rat myocardium and cultured cell lines yielded systematically negative results. Moreover, the nucleotide sequence analysis of the amplification products from patients with positive samples raised doubts about the true positivity of these samples.

CONCLUSIONS

This study suggests that the persistence of enteroviral RNA in dilated cardiomyopathy is not a major cause of the disease and that a careful analysis of polymerase chain reaction amplification products is essential in any study in which this technique is pushed to high sensitivity thresholds.

Search for persistent enterovirus infection of muscle in inflammatory myopathies

To investigate the hypothesis that the inflammatory muscle diseases (IMD) polymyositis (PM) and dermatomyositis (DM) may be due to a chronic, persistent enterovirus (EV) infection we sought to determine the prevalence of these viruses in muscle tissue using both nested polymerase chain reaction (PCR) and dot-blot hybridization assays. Thirty-six frozen muscle biopsies from 32 adult cases of IMD and 42 biopsies from 36 control subjects with other neuromuscular disorders were studied. Primers for PCR were chosen to conserved regions of the 5'-untranslated region of the EV genome. Constitutive Ableson tyrosine kinase (ABL) mRNA was detected by PCR to confirm the integrity of muscle RNA extracts. The sensitivity of the EV PCR was determined to be 40-400 copies (12.5-125 ag) of synthetic EV RNA transcript against a background of 1 microgram of cellular RNA. The specificity was assessed using a range of enteroviral and unrelated viral isolates extracted from cell cultures. Of the 78 samples tested, ABL mRNA was successfully detected in all but four samples. The time the biopsies spent in ultracold storage (1-73 months) did not appear to influence the integrity of extracted RNA. When assayed for EV RNA by nested PCR, none of 29 IMD cases (i.e., 28 PM and 1 DM) nor sequential biopsies from 3 PM patients were found to be positive. All 42 control biopsies were also negative for EV RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Psychosocial factors and chronic fatigue syndrome

This study investigated the number and severity of life events, Type A behaviour, coping strategies and social support differences between chronic fatigue and irritable bowel syndrome patients prior to illness and between these groups and healthy controls. Although few differences were found between the groups for life events, a number of interesting results emerged with regard to different aspects of Type A behaviour, various coping strategies and social support. These findings are discussed with respect to existing research in the field.

Detection of adenoviruses and enteroviruses in polluted waters by nested PCR amplification

A procedure has been developed for the rapid detection of enteroviruses and adenoviruses in environmental samples. Several systems for virus concentration and extraction of nucleic acid were tested by adding adenovirus type 2 and poliovirus type 1 to different sewage samples. The most promising method for virus recovery involved the concentration of viruses by centrifugation and elution of the virus pellets by treatment with 0.25 N glycine buffer, pH 9.5. Nucleic acid extraction by adsorption of RNA and DNA to silica particles was the most efficient. One aliquot of the extracted nucleic acids was used for a nested two-step PCR, with specific primers for all adenoviruses; and another aliquot was used to synthesize cDNA for a nested two-step PCR with specific primers for further detection of seeded polioviruses or all enteroviruses in the river water and sewage samples. The specificity and sensitivity were evaluated, and 24 different enterovirus strains and the 47 human adenovirus serotypes were recognized by the primers used. The sensitivity was estimated to be between 1 and 10 virus particles for each of the species tested. Twenty-five samples of sewage and polluted river water were analyzed and showed a much higher number of positive isolates by nested PCR than by tissue culture analysis. The PCR-based detection of enteroviruses and adenoviruses shows good results as an indicator of possible viral contamination in environmental wastewater.

Viruses, neurosis and fatigue

The evidence for viral infections as a cause of anxiety, depression and fatigue is reviewed. It is argued that in order to fully understand any proposed relationship the effects of psychosocial factors on immunity, convalescence and illness behaviour must be acknowledged.

Sequences specific for enterovirus detected in spinal cord from patients with motor neurone disease

OBJECTIVE

To investigate the association of enteroviruses with motor neurone disease, also known as amyotrophic lateral sclerosis.

DESIGN

Analysis by enterovirus polymerase chain reaction of wax embedded material from spinal cords taken at necropsy from subjects with motor neurone disease and from age and sex matched controls.

SETTING

Specimens were collected in the west of Scotland and in London between 1982 and 1992.

RESULTS

Sequences specific for a non-poliovirus type enterovirus were detected in spinal cord tissue from subjects with motor neurone disease. Amplification of a 414 base RNA target sequence in the conserved enterovirus 5' untranslated region from wax embedded tissue sections was successful in tissue from eight of 11 cases of sporadic motor neurone disease, one of two cases of familial motor neurone disease, and the one case of poliomyelitis, but not in the six matched controls or one case of antecedent poliomyelitis. In addition, sequences were detected in spinal cords from one monkey infected with wild type poliovirus and one monkey infected with polio vaccine. Comparison of sequences from cases of motor neurone disease with sequences of corresponding regions of the 5' untranslated regions of known picornaviruses showed them to be tightly grouped within the enterovirus genus closely related to coxsackievirus type B but not to polioviruses. Sequences derived from different parts of the spinal cord of the same subjects were identical, but sequences differed between individual subjects.

CONCLUSIONS

Conserved enteroviral sequences closely related to coxsackie B virus sequences were detectable in spinal cords from subjects with sporadic motor neurone disease and from one subject with possible familial motor neurone disease.

High titers of anti-Epstein-Barr virus DNA polymerase are found in patients with severe fatiguing illness

Forty-one patients with chronic fatigue syndrome (CFS), 76 healthy controls matched with the patient group for age range, sex, race, and socioeconomic class, and 22 symptomatic patients with seasonal affective disorder (SAD) had serum sampled for antibodies against 2 Epstein-Barr virus (EBV) replicating enzymes. Abnormal titers of antibodies were found twice as often in CFS patients as controls (34.1% vs. 17.1%), with SAD patients having an intermediate frequency (27.3%). Stratifying for disease severity sharpened the differences considerably, with the sicker CFS and SAD patients having 52% and 50% abnormal tests, respectively; more mildly afflicted CFS and SAD patients had a frequency of abnormal tests in the normal range. Antibodies to EBV DNA polymerase (DNAP) were the more sensitive of the two tests in that they were positive in all cases but one. These findings suggest that antibodies against EBV DNAP may be a useful marker in delineating a subset of patients with severe fatiguing illness for appropriate treatment trials and for monitoring their outcomes.

PCR for the diagnosis of enteroviral meningitis

A 2-step 'semi-nested' enterovirus PCR was developed and applied to CSF and serum specimens from 27 consecutive patients with aseptic meningitis. CSF and sera from 8 patients with non-enteroviral diagnoses were included as negative clinical controls. Enterovirus RNA was detected in CSF by PCR in 15 of the patients with aseptic meningitis, compared with 6 by virus culture. Acute-phase sera proved positive for enterovirus RNA in 11 patients, thus increasing the number of PCR-positive patients to 18. Convalescent-phase sera were all negative by PCR. The correlation of a positive or negative PCR result in CSF and/or serum versus combined conventional virology (serology and isolation from 1-3 sites, i.e. CSF, stool and throat) was 78%. All negative controls were negative by PCR. PCR is a reliable and sensitive diagnostic tool for the detection of enteroviral infections. Both CSF and acute-phase serum should be considered for testing.

Coxsackievirus B1-based antibody-capture enzyme-linked immunosorbent assay for detection of immunoglobulin G (IgG), IgM, and IgA with broad specificity for enteroviruses

An antibody-capture enzyme-linked immunosorbent assay (ELISA) with coxsackievirus B1 as the antigen was evaluated for detection of immunoglobulin G (IgG), IgM, and IgA antibodies and showed broad specificity for enteroviruses. In total, 116 serum or cerebrospinal fluid samples from 62 patients were tested by ELISA and the complement fixation test (CFT). Additionally, 15 serum samples that contained poliovirus-specific IgM antibody were tested. Serum samples from 200 healthy blood donors were used for standardization of the assays. The sensitivity of the ELISA varied with time of serum sampling, with a relatively low sensitivity when serum was collected within 3 days after the onset of symptoms (23%; 5 of 22) but good sensitivity when serum was collected later (83%; 20 of 24). The sensitivity was better than that of the CFT. The ELISAs were broadly reactive as concluded from typing of virus isolates that were simultaneously obtained. The assay did, furthermore, detect antibody against poliovirus type 3. Sera that contained rheumatoid factor, antinuclear antibody, or cardiolipin antibody (by the Venereal Disease Research Laboratory test) did not react in this ELISA. Nonspecific reactivity did occur, however, in cases of infectious mononucleosis and in Mycoplasma pneumoniae infection. The enterovirus-specific ELISA is found to be simple to perform, more sensitive than the CFT, and far less laborious than the neutralization test.

The polymerase chain reaction. Applications in dermatology

Within the space of the last 5 years, application of the revolutionary in vitro method of deoxyribonucleic acid (DNA) amplification known as the polymerase chain reaction (PCR), has become ubiquitous. The rapidly increasing number of clinical and research articles utilizing this technology, both in the dermatologic and general medical literature, requires one to have at least a basic understanding of how the PCR is conducted, what it has to offer, and the potential shortcomings. Such knowledge will hopefully allow a more critical appraisal of an increasingly complex literature. This review aims to describe the methodology and medical applications of this powerful technique with special consideration to the increasing role PCR may have on dermatologic research and practice.

Exercise performance and fatiguability in patients with chronic fatigue syndrome

To examine the role of delay in recovery of peripheral muscle function following exercise in the fatigue experienced by patients with the chronic fatigue syndrome (CFS) and to examine the influence of effort perception in limiting exercise performance in these patients, a study was carried out on a group of twelve patients with chronic fatigue syndrome and 12 sex and age-matched sedentary control subjects. Symptom limited incremental cycle exercise tests including measurements of perceived exertion were performed followed by examination of the contractile properties of the quadriceps muscle group for up to 48 hours. Muscle function was assessed by percutaneous electrical stimulation and maximum voluntary contractions. Muscle function at rest and during recovery was normal in CFS patients as assessed by maximum isometric voluntary contraction, 20:50 Hz tetanic force ratio and maximum relaxation rate. Exercise duration and the relationship between heart rate and work rate during exercise were similar in both groups. CFS patients had higher perceived exertion scores in relation to heart rate during exercise representing a reduced effort sensation threshold of 3.2 units on an unmodified Borg scale in CFS patients. Patients with chronic fatigue syndrome show normal muscle physiology before and after exercise. Raised perceived exertion scores during exercise suggest that central factors are limiting exercise capacity in these patients.

Polymyositis and dermatomyositis: no persistence of enterovirus or encephalomyocarditis virus RNA in muscle

OBJECTIVES

A persistent infection of enteroviruses and cardioviruses has been implicated in polymyositis and dermatomyositis, but conventional hybridisation studies of the presence of enterovirus RNA and encephalomyocarditis (EMC) virus RNA in affected muscle have yielded conflicting results. To investigate further the possibility of viral persistence, the presence of viral RNA in muscle from patients with adult onset polymyositis and dermatomyositis was investigated using a polymerase chain reaction (PCR) technique.

METHODS

Muscle tissue was obtained from 10 patients with polymyositis and five patients with dermatomyositis, all with adult onset active disease. A PCR was performed using primers with high specificity for enterovirus and EMC virus RNA, followed by Southern blot hybridisation with an oligonucleotide probe directed against the internal portion of the amplified product. A PCR directed against the Abelson tyrosine kinase mRNA served as an internal control for the presence and quality of RNA.

RESULTS

A specific amplification for enterovirus or for EMC virus could not be seen in any of the muscle biopsy samples, despite a sensitivity of about 30 plaque forming units for enterovirus and of 100 plaque forming units for EMC virus. Southern blot hybridisation confirmed these results in that positive controls hybridised with the oligonucleotide probe, but no signal was obtained with the muscle specimens.

CONCLUSION

A sensitive and specific PCR technique showed no evidence of the presence of enterovirus or EMC virus RNA in muscle samples from patients with polymyositis or dermatomyositis. These data do not support the proposal that viral RNA persistence plays a part in these idiopathic inflammatory myopathies.

Biochemical and muscle studies in patients with acute onset post-viral fatigue syndrome

AIMS

To investigate in detail various biochemical and pathophysiological indices of muscle pathology in acute onset post-viral fatigue syndrome (PVFS).

METHODS

Twenty three patients with PVFS (of mean duration 4.6 years) were subjected to needle biopsy for histomorphometry and total RNA contents. Plasma analysis included serology and creatine kinase activities. Indices of whole body mass were also measured--namely, whole body potassium content and plasma carnosinase activities.

RESULTS

About 80% of the patients had serology indicative of persistent enteroviral infection as determined by VP1 antigen assay. Only about 10% of that same group of patients had serological indications of current enterovirus infection by IgM assay; a separate subset of 10% showed antibody changes suggestive of reactivation of Epstein-Barr virus. Quantitative morphometric analysis of skeletal muscle fibres indicated that the quadriceps muscle was normal or displayed only minor abnormalities in 22 patients. The Quetelet's Index (body mass index) and whole-body potassium values (index of lean body mass) were not affected in PVFS. The mean plasma carnosinase and creatinine kinase activities were also generally normal in these patients. The mean muscle RNA composition--mg RNA/mg DNA: was significantly reduced in acute onset PVFS by about 15%. The protein:DNA ratio was not significantly affected.

CONCLUSIONS

Patients with acute onset PVFS, therefore, lose muscle protein synthetic potential, but not muscle bulk. Histopathology is consistent with these observations. These perturbations may contribute to the apparent feature of perceived muscle weakness associated with the persistent viral infection in the muscle themselves.

Nested polymerase chain reaction for high-sensitivity detection of enteroviral RNA in biological samples

A method based on nested polymerase chain reaction was developed for the detection of enteroviral genomes in biological samples. By taking advantage of the conserved 5' noncoding region of the enteroviral RNA, two sets of primers were utilized, enabling the detection either of a broad range of enteroviruses or of group B coxsackieviruses only. The sensitivity of the method is close to the detection of single molecules of viral RNA in as much as 1 mg of tissue sample. A preliminary study showed the usefulness of this technique for the analysis of endomyocardial biopsy samples from patients with idiopathic dilated cardiomyopathy and myocarditis.

Demonstration of Coxsackie virus RNA in formalin-fixed tissue sections from childhood myocarditis cases by in situ hybridization and the polymerase chain reaction

This is a combined study using in situ hybridization and the polymerase chain reaction to investigate the presence of Coxsackie virus RNA in formalin-fixed tissue from cases of childhood myocarditis. Of the ten cases studied, two were positive by both methods. The virus RNA was predominantly located in areas showing an inflammatory cell infiltrate and myofibre necrosis. These findings suggest that direct lytic infection of myocytes by virus is responsible for myocarditis in these cases, rather than an autoimmune process, which has been suggested previously. The findings in one case, where the virus showed a marked sub-endocardial distribution, may have implications for the aetiology of endocardial fibroelastosis by confirming a viral tropism for this location. The techniques used in this study are easily repeatable and can be directly applied to look for viruses in a number of other diseases where a viral aetiology is suspected.

[Chronic fatigue syndrome: a critical review]

The term "chronic fatigue syndrome" (CFS) applies to a condition of unknown aetiology characterized clinically by an association of subjective symptoms, the most constant being an invalidating tiredness. The diagnostic criteria in current use do not permit to isolate an homogeneous subgroup among patients consulting for chronic asthenia. In the present state of research no infectious or immunological cause has been demonstrated conclusively, although a persistent enterovirus or herpesvirus type 6 infection or a state of chronic immune activation seem to play a role in some cases. Patients who fulfill the criteria of CFS present with psychiatric overmorbidity, essentially depressive, and in 50% of the cases with the mental disorders preceding CFS. The various theoretical models linking CFS to psychopathology are discussed, and finally the syndrome is regarded as a social construction reproducing or renovating the neurasthenia of the late 19th century. There is no specific treatment of CFS, but antidepressants, cognitive-behavioural therapy and perhaps certain immuno-modulators can be useful. The future lines of research should endeavour to isolate a subgroup of patients with prolonged asthenia after a recognized episode of infection and to identify the immunological, psychological and behavioral characteristics of this particular group as well as their reciprocal interactions.

Simple technique for detecting RNA viruses by PCR in single sections of wax embedded tissue

The detection of specific RNA species in wax-embedded tissue sections using the polymerase chain reaction (PCR) means that gene expression can be studied and RNA viruses detected in stored histological tissue samples. This technique potentially allows the distribution of gene expression and viral replication to be studied in finely subdivided tissues. A technique is presented that has been used successfully to detect short RNA target sequences (130-420 bases) from proto-oncogene Abelson, human enteroviruses, and the sheep retrovirus Maedi-Visna virus using RNA PCR in single wax sections (20-30 microns). Various tissues were used which had not been deliberately prepared for this purpose. In a simple procedure hot xylene dewaxing is followed by acid phenol extraction of RNA and RNA PCR.

Chronic fatigue syndrome. A fresh look at an old problem

Chronic fatigue syndrome (CFS), an organic disease of unexplained origin, affects about three people in 100,000. Symptoms last approximately 2 1/2 years, and most CFS patients return to normal health. Diagnosis of CFS is by exclusion. No single remedy has yet proven consistently beneficial. Family physicians can help by providing medical validation of disability to persons who might otherwise be seen as malingerers.

Rapid diagnosis of enterovirus infection by magnetic bead extraction and polymerase chain reaction detection of enterovirus RNA in clinical specimens

We describe a rapid method for extraction and detection of enterovirus RNA in clinical samples. By using magnetic bead technology, enterovirus RNA was efficiently and rapidly extracted from cerebrospinal fluid, stool, saliva, blood, pericardial fluid, urine, and cryopreserved or formalin-fixed solid tissue. Enterovirus RNA was then detected by reverse transcription followed by polymerase chain reaction amplification with primers designed to allow detection of most enterovirus serotypes. For detection of enteroviruses in specimens from patients with acute enteroviral disease, the overall sensitivity of enzymatic RNA amplification was greater than that of cell culture isolation, especially in blood specimens and in stool specimens from patients with acute cardiac disease. Enterovirus RNA was also detected in cryopreserved and archival formalin-fixed myocardial tissue from patients with acute myocarditis and chronic dilated cardiomyopathy. The ability to study archival specimens is of particular value in conducting retrospective investigation. The RNA extraction procedure used was considerably faster than extraction methods using organic reagents, used less hazardous reagents, and was of similar sensitivity. This detection protocol may therefore be useful both for the diagnosis of enterovirus infection and in studying the pathogenesis of acute and chronic enterovirus-induced disease.

Search for retrovirus in the chronic fatigue syndrome

AIM

To examine peripheral blood and skeletal muscle from patients with chronic fatigue syndrome for exogenous retrovirus.

METHODS

Blood samples from 30 patients and muscle biopsy specimens of 15 patients were examined for retroviral sequences by DNA extraction, polymerase chain reaction (PCR), and Southern blotting hybridisation. Sera were examined for human foamy virus by western immunoblotting and indirect immunofluorescence techniques.

RESULTS

No differences between the patient and control populations was found for any of the PCR primer sets used (gag, pol, env, and tax regions of HTLV I/II). An endogenous gag band was observed in both the patient and control groups. All sera were negative for antibody to human foamy virus.

CONCLUSION

The results indicate that there is no evidence of retroviral involvement in the chronic fatigue syndrome.

Serum IgA, IgG, and IgM responses to different enteroviruses as measured by a coxsackie B5-based indirect ELISA

An enterovirus-specific indirect ELISA, based on a single local isolate of coxsackie B5 as antigen, was used to study the IgA, IgG, and IgM responses in 19 patients with a recent or current enterovirus infection. Twelve different enterovirus serotypes were isolated from 15 patients. Paired serum samples were available from 10 and a single serum from 5 of these 15 patients. In addition, 4 patients diagnosed by a significant titer rise of complement fixing antibodies to enterovirus were included. A serological diagnosis, defined as an increase in titer of enterovirus IgG and/or presence of enterovirus IgM, were established in all 14 patients with paired sera. Enterovirus IgM was present in either a single serum or in both sera in 13 of them. Out of 5 patients with a single serum sample only, enterovirus IgA or enterovirus IgM was found in 4. Specific IgA was present in either a single serum or in both sera in 14 of the 19 patients. Seven of the 10 enterovirus isolate patients with paired sera had a significant titer rise of complement fixing antibodies; however, all 10 were diagnosed by ELISA. Among 64 healthy controls 2 had enterovirus IgA and none had enterovirus IgM. In conclusion, the use of a single antigen-based ELISA was found to be reliable for the diagnosis of recent and current enterovirus infections.

Possible upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome

OBJECTIVE

To study the dynamic function of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome.

DESIGN

Prospective comparison of patients with postviral fatigue syndrome with two control groups.

SETTING

Department of neurology, University of Glasgow, Southern General Hospital; department of psychiatry, St James's Hospital, Dublin.

SUBJECTS

15 patients with postviral fatigue syndrome, 13 age and sex matched healthy subjects, and 13 patients with primary depression.

MAIN OUTCOME MEASURES

Serum prolactin concentrations before and one, two, and three hours after administration of buspirone.

RESULTS

Because of the effects of sex hormones on prolactin secretion data for men and women were analysed separately. There was no significant difference in baseline prolactin concentrations between patients with postviral fatigue syndrome and healthy subjects or those with primary depression. However, the percentage difference between peak and baseline values was significantly higher in patients with postviral fatigue syndrome than the control groups (one way analysis of variance: women, p = 0.003; men, p = 0.004).

CONCLUSIONS

The results suggest upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome but not in those with primary depression. The buspirone challenge test may therefore be useful in distinguishing these two conditions. Larger studies are required to explore the potential value of drugs acting on central 5-hydroxytryptamine receptors in the treatment of patients with the postviral fatigue syndrome.

Non-cytopathic infection of rhabdomyosarcoma cells by coxsackie B5 virus

Infection of rhabdomyosarcoma (RD) cells by coxsackie B5 virus (CBV5) was non-cytopathic, although low titres of infectious virus were produced after 24 h post-infection. The extent of CBV5 replication in RD cells increased after sequential passage of the virus in these cells. The RD cells from the first cycle of CBV5 infection were recovered and maintained in culture for 3 months (equivalent to 21 passages) releasing infectious virus throughout this period; these cells were considered to be persistently infected with CBV5 and were designated piRD cells. Coxsackie virus antigen was demonstrated in a small proportion of piRD cells by immunofluorescence staining. High resolution two-dimensional polyacrylamide gel electrophoresis was used to analyse the intracellular proteins prepared from piRD cells, three proteins were detected which were absent in uninfected RD cells. These new proteins were similar in charge to virus proteins induced during CBV5 lytic infection of HEp-2 cells. Quantitative densitometry of 2-dimensional protein profiles of piRD and uninfected cells showed no significant disruption of RD cell protein synthesis by the persistent virus infection. Three cloned cell lines were recovered from piRD cells, none of which showed evidence of infectious virus or virus-induced protein synthesis suggesting that the parental cell line was a carrier culture for CBV5.