Category: Pathogenesis

Studies on enterovirus in patients with chronic fatigue syndrome

Abstract:

A large study on 121 patients with the chronic fatigue syndrome (CFS) that examined muscle biopsy samples for enterovirus by means of polymerase chain reaction analysis was carried out. The results were compared with those obtained from 101 muscle biopsy specimens from patients with a variety of other neuromuscular disorders (OND), including neurogenic atrophies, dystrophies, and mitochondrial, metabolic, and endocrine myopathies.

Thirty-two (26.4%) of the biopsy specimens from the group of patients with CFS were positive, compared with 20 (19.8%) from the group of patients with OND, a difference that was not significant.

This finding is in contrast to those of our previous smaller study in which significantly more patients with CFS than control subjects (53% [32 of 60] vs. 15% [6 of 41]) had enterovirus RNA sequences in their muscle. It was concluded that it is unlikely that persistent enterovirus infection plays a pathogenetic role in CFS, although an effect in initiating the disease process cannot be excluded.

 

Source: Gow JW, Behan WM, Simpson K, McGarry F, Keir S, Behan PO. Studies on enterovirus in patients with chronic fatigue syndrome. Clin Infect Dis. 1994 Jan;18 Suppl 1:S126-9. http://www.ncbi.nlm.nih.gov/pubmed/8148439

 

Pathogenic tracks in fatigue syndromes

Abstract:

This review analyses the recent literature devoted to two related fatigue syndromes: chronic fatigue syndrome (CFS) and acute onset postviral fatigue syndrome (PVFS). The articles are grouped into five pathogenic tracks: infectious agents, immune system, skeletic muscle, hypothalamo-pituitary-adrenal (HPA) axis and psychiatric factors.

Although a particular infectious agent is unlikely to be responsible for all CFS cases, evidence is shown that host-parasite relationships are modified in a large proportion of patients with chronic fatigue. Antibody titres against infectious agents are often elevated and replication of several viruses could be increased.

Chronic activation of the immune system is also observed and could be due to the reactivation of persistent or latent infectious agents such as herpes viruses (i.e. HHV-6) or enteroviruses. It could also be favorised by an impaired negative feedback of the HPA axis on the immune system.

A model is proposed where the abnormalities of the HPA axis are primary events and are mainly responsible for a chronic activation of the immune system which in turn induces an increased replication of several viruses under the control of cellular transcription factors. These replicating viruses together with cytokines such as TNF-alpha would secondarily induce functional disorders of muscle and several aspects of asthenia itself.

 

Source: Moutschen M, Triffaux JM, Demonty J, Legros JJ, Lefèbvre PJ. Pathogenic tracks in fatigue syndromes. Acta Clin Belg. 1994;49(6):274-89. http://www.ncbi.nlm.nih.gov/pubmed/7871934

 

Human herpesvirus 6 and chronic fatigue syndrome

Abstract:

The cause of chronic fatigue syndrome (CFS) is still enigmatic. Using indirect immunofluorescence testing for measuring antibody against human herpesvirus 6 (HHV-6), this study investigated the association of CFS with infection by HHV-6. Seventeen patients (group A) fulfilling the Centers for Disease Control (CDC) definition for CFS were compared with eight patients (group B) with chronic fatigue but not meeting the CDC criteria.

No significant difference was found between the two groups for 30 parameters including sex, age, exposure to children and serology for Epstein-Barr virus, cytomegalovirus, herpes simplex virus, and toxoplasma. Univariate analysis showed that patients in group A complained more frequently of a sore throat, headache and of recurrent type of fatigue.

These three parameters are discriminant in identifying patients who will meet the CDC case definition of CFS. The titre of antibody against HHV-6 in group A (1:99) was significantly higher than in group B (1:15) (P=0.007). Elevated HHV-6 titres suggests that this virus could be a cofactor in the pathogenesis of CFS.

 

Source: Eymard D, Lebel F, Miller M, Turgeon F. Human herpesvirus 6 and chronic fatigue syndrome. Can J Infect Dis. 1993 Jul;4(4):199-202. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3250792/  (Full article)

 

Enteroviruses and postviral fatigue syndrome

Abstract:

Postviral fatigue syndrome (PFS) occurs both in epidemics and sporadically. Many of the original epidemics were related to poliomyelitis outbreaks which either preceded or followed them.

The core clinical symptoms are always the same: severe fatigue made worse by exercise, myalgia, night sweats, atypical depression and excessive sleep. The other common symptoms include dysequilibrium disorders and irritable bowel syndrome.

We have detected enteroviral genome sequences in muscle biopsies from cases of PFS, using specific enteroviral oligonucleotide primers in the polymerase chain reaction (PCR). In addition, whole virus particles can be demonstrated in PCR-positive muscle, using solid-phase immuno-electron microscopy.

An increase in the number and size of muscle mitochondria was found in 70% of PFS cases, suggesting an abnormality in metabolic function. Evidence of hypothalamic dysfunction was present, particularly involving 5-hydroxytryptamine metabolism.

A putative model of PFS, based on persistent enteroviral infection in laboratory mice, revealed resolving inflammatory lesions in muscle with, however, a marked increase in the production of certain cytokines in the brain. This model may help to explain the pathogenesis of PFS.

 

Source: Behan PO, Behan WM, Gow JW, Cavanagh H, Gillespie S. Ciba Found Symp. 1993;173:146-54; discussion 154-9. http://www.ncbi.nlm.nih.gov/pubmed/8387908

 

Chronic fatigue syndrome–study of 51 cases treated at the Second Tokyo National Hospital

Abstract:

Fifty-one patients with chronic fatigue syndrome (CFS) were studied. Tender points, which are a characteristic clinical feature of fibromyalgia, were found in all but two of the patients at 11.4 points (mean) per patient. IgG antibody titers to EB virus viral capsid antigen were more elevated in the CFS patient group compared to that of the control (p < 0.0015). IgG antibody titers to HHV-6 were not higher in the patient group. NK cell activity was not more decreased in the patient group, whereas, the mean number of NK cells was lower (p < 0.005) in the patient group, when CD57 was used as the NK cell marker. Viral infections and/or disorders in cellular immunity may be important factors in the pathogenesis of CFS.

 

Source: Nishikai M. Chronic fatigue syndrome–study of 51 cases treated at the Second Tokyo National Hospital. Nihon Rinsho. 1992 Nov;50(11):2641-7. [Article in Japanese] http://www.ncbi.nlm.nih.gov/pubmed/1337560

 

Overview of our patients with chronic fatigue syndrome (CFS) from the pathoetiological aspects

Abstract:

We interviewed 285 patients who visited our department claiming with a complaint of chronic fatigue syndrome (CFS) and subsequently diagnosed 55 as having CFS, according to the criteria for CFS of the centers for disease control (CDC). We measured various virus antibody titers, 2-5, adenylate synthetase levels in the serum lymphocyte subset in blood, employing a double staining technique with monoclonal antibodies. In this paper, we pathoetiology of CFS, based on our findings and other researchers’ is discussed.

 

Source: Matsuda J, Gohchi K. Overview of our patients with chronic fatigue syndrome (CFS) from the pathoetiological aspects. Nihon Rinsho. 1992 Nov;50(11):2635-40. [Article in Japanese] http://www.ncbi.nlm.nih.gov/pubmed/1287240

 

Assessment of regional cerebral perfusion by 99Tcm-HMPAO SPECT in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a severely disabling illness of uncertain aetiology. It is characterized by a chronic, sustained or fluctuating sense of debilitating fatigue without any other known underlying medical conditions. It is also associated with both somatic and neuropsychological symptoms. Both physical and laboratory findings are usually unremarkable.

Regional cerebral blood flow (rCBF) was assessed in 60 clinically defined CFS patients and 14 normal control (NC) subjects using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) single photon emission computed tomography (SPECT). Compared with the NC group, the CFS group showed significantly lower cortical/cerebellar rCBF ratios, throughout multiple brain regions (P < 0.05). Forty-eight CFS subjects (80%) showed at least one or more rCBF ratios significantly less than normal values.

The major cerebral regions involved were frontal (38 cases, 63%), temporal (21 cases, 35%), parietal (32 cases, 53%) and occipital lobes (23 cases, 38%). The rCBF ratios of basal ganglia (24 cases, 40%) were also reduced. 99Tcm-HMPAO brain SPECT provided objective evidence for functional impairment of the brain in the majority of the CFS subjects. The findings may not be diagnostic of CFS but 99Tcm-HMPAO SPECT may play an important role in clarifying the pathoaetiology of CFS. Further studies are warranted.

 

Source: Ichise M, Salit IE, Abbey SE, Chung DG, Gray B, Kirsh JC, Freedman M. Assessment of regional cerebral perfusion by 99Tcm-HMPAO SPECT in chronic fatigue syndrome. Nucl Med Commun. 1992 Oct;13(10):767-72. http://www.ncbi.nlm.nih.gov/pubmed/1491843

 

Fluctuations in perceived energy and mood among patients with chronic fatigue syndrome

Comment in: Fluctuations in perceived energy and mood among patients with chronic fatigue syndrome. [J R Soc Med. 1992]

Comment on: Fluctuations in perceived energy and mood among patients with chronic fatigue syndrome. [J R Soc Med. 1992]

 

I find it surprising that Wood et al. (April 992 JRSM, p 195) no longer appear to consider,that the presence of a precipitating infection should be necessary for the selection of patients involved in the study of chronic fatigue syndromes. The reference they quote, which refers to guidelines laid down at Oxford in 1990, states very clearly that post-infectious patients with chronic fatigue do indeed form a distinct subgroup, and that to fulfil research criteria there, must be,’definite evidence of infection at onset or presentation’.

Having failed to make such a distinction it is not, altogether surprising that they go on to conclude that the higher levels of depression found in their study …. serve to reinforce the now widely–current, notion that such patients may be suffering from a depressive illness, of which physical fatigue is a somatic manifestation’.

You may read the rest of this comment as well as the author’s response here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1293670/pdf/jrsocmed00107-0092b.pdf

 

Source: Shepherd C. Fluctuations in perceived energy and mood among patients with chronic fatigue syndrome. J R Soc Med. 1992 Sep;85(9):588. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1293670/

 

Immunologically mediated fatigue: a murine model

Abstract:

Chronic fatigue syndrome (CFS) is an idiopathic disorder in which the chief symptoms is profound fatigue. To explore the relationship between immune stimulation and fatigue, we developed a murine model for quantifying fatigue: reduction in voluntary running and delayed initiation of grooming after swimming.

Inoculation of female BALB/c mice with Corynebacterium parvum antigen or the relatively avirulent Me49 strain of Toxoplasma gondii induced fatigue: baseline running reduced to less than 50 and 30% for 8 and 14 days, respectively, and delayed initiation of grooming after swimming in both immunologically stimulated groups.

A threefold evaluation of serum transforming growth factor-beta levels, a cytokine increased in CFS patients, was found in fatigued C. parvum- and T. gondii-inoculated mice. This murine model appears promising for investigation of the pathogenesis of immunologically mediated fatigue.

 

Source: Chao CC, DeLaHunt M, Hu S, Close K, Peterson PK. Immunologically mediated fatigue: a murine model. Clin Immunol Immunopathol. 1992 Aug;64(2):161-5. http://www.ncbi.nlm.nih.gov/pubmed/1643746

 

Serum levels of lymphokines and soluble cellular receptors in primary Epstein-Barr virus infection and in patients with chronic fatigue syndrome

Abstract:

The immunopathology in primary Epstein-Barr virus (EBV) infections and in chronic fatigue syndrome was studied by examining serum levels of interleukins (IL) and of soluble T cell receptors in serum samples.

Serum samples were from patients during and 6 months after primary EBV-induced infectious mononucleosis and from patients with chronic fatigue syndrome and serologic evidence of EBV reactivation. Markers for T lymphocyte activation (soluble IL-2 and CD8) and for monocyte activation (neopterin) were significantly elevated during acute infectious mononucleosis but not in patients with chronic fatigue syndrome.

Interferon-alpha, IL-1 beta, and IL-6 levels were not significantly increased in any patient group but inferferon-gamma levels were significantly increased during the acute phase of infectious mononucleosis. The levels of IL-1 alpha were significantly higher than in controls both in patients with infectious mononucleosis and in those with chronic fatigue syndrome. In the latter, the lack of most markers for lymphocyte activation found in patients with infectious mononucleosis makes it less likely that EBV reactivation causes symptoms.

 

Source: Linde A, Andersson B, Svenson SB, Ahrne H, Carlsson M, Forsberg P, Hugo H, Karstorp A, Lenkei R, Lindwall A, et al. Serum levels of lymphokines and soluble cellular receptors in primary Epstein-Barr virus infection and in patients with chronic fatigue syndrome. J Infect Dis. 1992 Jun;165(6):994-1000. http://www.ncbi.nlm.nih.gov/pubmed/1316417