Category: Pathogenesis

Acute enterovirus infection followed by myalgic encephalomyelitis/chronic fatigue syndrome(ME/CFS) and viral persistence

Abstract:

AIMS: Enteroviruses are well-known causes of acute respiratory and/or gastrointestinal infections and non-specific flu-like illness. Although enterovirus protein, RNA and non-cytopathic viruses have been demonstrated in the stomach biopsies of patients with myalgia encephalomyelitis/chronic fatigue syndrome (ME/CFS), causality for chronic diseases is difficult to establish without having well-documented cases of acute enterovirus infections. The aim of this study was to link acute enteroviral infection to viral persistence in patients with ME/CFS.

METHOD: Patients admitted to the hospital with acute febrile illnesses were screened for enteroviral infections. Acutely infected patients were followed longitudinally, and those who developed symptoms of ME/CFS underwent oesophagogastroduodenoscopy and biopsies of the antrum to document viral persistence by immunoperoxidase staining for viral protein and viral RNA assay.

RESULTS: Three representative patients with different manifestations of acute enterovirus infections progressed to have chronic symptoms of ME/CFS. Persistent viral infection was demonstrated in the antrum years later.

CONCLUSION: After acute infections, enteroviruses can persist in patients resulting in manifestation of ME/CFS. Chronic enterovirus infection in an immunocompetent host may be an example of a stalemate between attenuated, intracellular viruses and an ineffective immune response.

 

Source: Chia J, Chia A, Voeller M, Lee T, Chang R. Acute enterovirus infection followed by myalgic encephalomyelitis/chronic fatigue syndrome(ME/CFS) and viral persistence. J Clin Pathol. 2010 Feb;63(2):165-8. doi: 10.1136/jcp.2009.070466. Epub 2009 Oct 14. https://www.ncbi.nlm.nih.gov/pubmed/19828908

 

Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a debilitating disease of unknown etiology that is estimated to affect 17 million people worldwide. Studying peripheral blood mononuclear cells (PBMCs) from CFS patients, we identified DNA from a human gammaretrovirus, xenotropic murine leukemia virus-related virus (XMRV), in 68 of 101 patients (67%) as compared to 8 of 218 (3.7%) healthy controls. Cell culture experiments revealed that patient-derived XMRV is infectious and that both cell-associated and cell-free transmission of the virus are possible. Secondary viral infections were established in uninfected primary lymphocytes and indicator cell lines after their exposure to activated PBMCs, B cells, T cells, or plasma derived from CFS patients. These findings raise the possibility that XMRV may be a contributing factor in the pathogenesis of CFS.

Comment in:

Erratum in: Partial retraction. Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome. [Science. 2011]

Retraction in: Retraction. [Science. 2011]

 

Source: Lombardi VC, Ruscetti FW, Das Gupta J, Pfost MA, Hagen KS, Peterson DL, Ruscetti SK, Bagni RK, Petrow-Sadowski C, Gold B, Dean M, Silverman RH, Mikovits JA. Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome. Science. 2009 Oct 23;326(5952):585-9. doi: 10.1126/science.1179052. Epub 2009 Oct 8. http://science.sciencemag.org/content/326/5952/585.long (Full article)

 

Cardiac function fluctuates during exacerbation and remission in young adults with chronic fatigue syndrome and “small heart”

Abstract:

BACKGROUND: “Small heart syndrome”, previously referred to as so-called “neurocirculatory asthenia” associated with a small heart shadow on the chest roentgenogram, is characterized by weakness or fatigue even after mild exertion, palpitation, dyspnea, and fainting, many of which resemble symptoms in patients with chronic fatigue syndrome (CFS).

METHODS AND RESULTS: The study population comprised 42 patients with CFS younger than 40 years of age. Cardiothoracic ratio was determined on the chest roentgenogram and echocardiographic examination was performed to evaluate both the cardiac chamber size and function. “Small heart” (cardiothoracic ratio < or = 42%) on the chest X-ray photograph was noted in 26 (62%) of the study CFS patients. Echocardiographic examination demonstrated significantly smaller mean values of both the left ventricular (LV) end-diastolic and end-systolic dimensions, stroke volume indexes and cardiac indexes in CFS patients with “small heart” than in those without it and also in 20 control subjects. Thus, CFS patients with “small heart” had an actually small LV chamber and poor cardiac performance. During a long follow-up period of 10 CFS patients with “small heart”, all echocardiographic parameters mentioned above improved and cardiothoracic ratios increased significantly during the remission phase as compared with exacerbation phase.

CONCLUSIONS: “Small heart” on the chest X-ray photograph was prevalently noted in CFS patients. Echocardiographic examination revealed that CFS patients with “small heart” had an actually small LV chamber and poor cardiac performance. Cardiac functional changes evaluated by repeated examinations appeared to be directly associated with the severity of their symptoms. Small heart syndrome with impaired cardiac function may contribute to the development of CFS through low cardiac output as a constitutional factor.

 

Source: Miwa K, Fujita M. Cardiac function fluctuates during exacerbation and remission in young adults with chronic fatigue syndrome and “small heart”. J Cardiol. 2009 Aug;54(1):29-35. doi: 10.1016/j.jjcc.2009.02.008. Epub 2009 Mar 28. http://www.journal-of-cardiology.com/article/S0914-5087(09)00066-5/fulltext (Full article)

 

Functional characterization of muscle fibres from patients with chronic fatigue syndrome: case-control study

Abstract:

Chronic fatigue syndrome (CFS) is a disabling condition characterized by unexplained chronic fatigue that impairs normal activities. Although immunological and psychological aspects are present, symptoms related to skeletal muscles, such as muscle soreness, fatigability and increased lactate accumulation, are prominent in CFS patients.

In this case-control study, the phenotype of the same biopsy samples was analyzed by determining i) fibre-type proportion using myosin isoforms as fibre type molecular marker and gel electrophoresis as a tool to separate and quantify myosin isoforms, and ii) contractile properties of manually dissected, chemically made permeable and calcium-activated single muscle fibres.

The results showed that fibre-type proportion was significantly altered in CSF samples, which showed a shift from the slow- to the fast-twitch phenotype. Cross sectional area, force, maximum shortening velocity and calcium sensitivity were not significantly changed in single muscle fibres from CSF samples. Thus, the contractile properties of muscle fibres were preserved but their proportion was changed, with an increase in the more fatigue-prone, energetically expensive fast fibre type.

Taken together, these results support the view that muscle tissue is directly involved in the pathogenesis of CSF and it might contribute to the early onset of fatigue typical of the skeletal muscles of CFS patients.

 

Source: Pietrangelo T, Toniolo L, Paoli A, Fulle S, Puglielli C, Fanò G, Reggiani C. Functional characterization of muscle fibres from patients with chronic fatigue syndrome: case-control study. Int J Immunopathol Pharmacol. 2009 Apr-Jun;22(2):427-36. https://www.ncbi.nlm.nih.gov/pubmed/19505395

 

Chronic fatigue syndrome with autoantibodies–the result of an augmented adjuvant effect of hepatitis-B vaccine and silicone implant

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) that defines by prolonged fatigue and other manifestations, was recently integrated into a spectrum of central sensitivity syndromes including several diseases as fibromylagia. CFS etiology is multi-factorial commonly triggered by infectious agents. Vaccines, induce an immune response similarly to infections, and may trigger just like infections autoimmune diseases, CFS and fibromyalgia. Furthermore vaccines contain an adjuvant which enhances their immune stimulation.

CASE PRESENTATION: A 56-year-old woman was diagnosed with CFS accompanied by fibromyalgia, demyelination and autoantibodies. Her illness begun following the 2nd dose of hepatitis-B vaccine, and was aggravated by the 3rd vaccination. She underwent silicone breast implantation 6 years before vaccination with no adverse events. However, between the 2nd and 3rd vaccination she suffered a breast injury with local inflammation. Upon explanation of her breast implants silicone leak was observed.

DISCUSSION: Vaccines have been reported to precede CFS mainly following exposure to multiple vaccinations (e.g. the Gulf war syndrome), or as an adverse response to the vaccine adjuvant (e.g. the macrophagic myofasciitis syndrome). Silicone is considered an adjuvant to the immune system, and may induce “the adjuvant disease”. Silicone implant, especially silicone leak relationship with autoimmunity and CFS has been the focus of considerable debates.

CONCLUSION: Our patient illness started following hepatitis-B vaccine, suggesting that it was caused or accelerated by vaccination. In parallel to vaccination our patient suffered from breast injury, which might represent the time of silicone leak. The exposure to the adjuvant, silicone, might have augmented her immune response to the vaccine. To the best of our knowledge this is the first case of combined adverse effect to vaccine and silicone. Vaccine safety in individuals with silicone implants requires further studies.

 

Source: Nancy AL, Shoenfeld Y. Chronic fatigue syndrome with autoantibodies–the result of an augmented adjuvant effect of hepatitis-B vaccine and silicone implant. Autoimmun Rev. 2008 Oct;8(1):52-5. doi: 10.1016/j.autrev.2008.07.026. Epub 2008 Aug 24. https://www.ncbi.nlm.nih.gov/pubmed/18725327

 

Possible role for early-life immune insult including developmental immunotoxicity in chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME)

Abstract:

Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME) in some countries, is a debilitating disease with a constellation of multi-system dysfunctions primarily involving the neurological, endocrine and immune systems. While substantial information is available concerning the complex dysfunction-associated symptoms of CFS, environmental origins of the disease have yet to be determined.

Part of the dilemma in identifying the cause(s) has been the focus on biomarkers (hormones, neurotransmitters, cytokines, infectious agents) that are contemporary with later-life CFS episodes. Yet, recent investigations on the origins of environmental diseases of the neurological, endocrine, reproductive, respiratory and immune systems suggest that early life toxicologic and other insults are pivotal in producing later-life onset of symptoms. As with autism and childhood asthma, CFS can also occur in children where the causes are certainly early-life events.

Immune dysfunction is recognized as part of the CFS phenotype but has received comparatively less attention than aberrant neurological or endocrine function. However, recent research results suggest that early life immune insults (ELII) including developmental immunotoxicity (DIT), which is induced by xenobiotics, may offer an important clue to the origin(s) of CFS.

The developing immune system is a sensitive and novel target for environmental insult (xenobiotic, infectious agents, stress) with major ramifications for postnatal health risks. Additionally, many prenatal and early postnatal neurological lesions associated with postnatal neurobehavioral diseases are now recognized as linked to prenatal immune insult and inflammatory dysregulation. This review considers the potential role of ELII including DIT as an early-life component of later-life CFS.

 

Source: Dietert RR, Dietert JM. Possible role for early-life immune insult including developmental immunotoxicity in chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME). Toxicology. 2008 May 2;247(1):61-72. doi: 10.1016/j.tox.2008.01.022. Epub 2008 Feb 8. https://www.ncbi.nlm.nih.gov/pubmed/18336982

 

Chronic fatigue syndrome: characteristics and possible causes for its pathogenesis

Abstract:

Chronic fatigue syndrome is a heterogeneous disorder with unknown pathogenesis and etiology, characterized by disabling fatigue, difficulty in concentration and memory, and concomitant skeletal and muscular pain. Several mechanisms have been suggested to play a role in CFS, such as excessive oxidative stress following exertion, immune imbalance characterized by decreased natural killer cell and macrophage activity, immunoglobulin G subclass deficiencies (IgG1, IgG3) and decreased serum concentrations of complement component. Autoantibodies were also suggested as a possible factor in the pathogenesis of CFS. Recent studies indicate that anti-serotonin, anti-microtubule-associated protein 2 and anti-muscarinic cholinergic receptor 1 may play a role in the pathogenesis of CFS. It has been demonstrated that impairment in vasoactive neuropeptide metabolism may explain the symptoms of CFS.

 

Source: Bassi N, Amital D, Amital H, Doria A, Shoenfeld Y. Chronic fatigue syndrome: characteristics and possible causes for its pathogenesis. Isr Med Assoc J. 2008 Jan;10(1):79-82. http://www.ima.org.il/IMAJ/ViewArticle.aspx?year=2008&month=01&page=79 (Full article)

 

Genetic background of chronic fatigue syndrome

Abstract:

Although previous twin and family studies have suggested the involvement of genetic factor(s) in the pathogenesis of chronic fatigue syndrome (CFS), responsible gene for CFS was not known. We have recently reported the association of serotonin transporter gene polymorphism in CFS. A significant increase of longer (L and XL) alleic variants was found in the CFS patients compared to the controls. Compared to S allele, the L allele is believed to retain higher transcriptional activity, which causes decreased concentration of serotonin in the extracellular space, namely, active serotonin in CFS. These results thus support the serotonin hypothesis in the pathogenesis of CFS.

 

Source: Narita M, Narita N. Genetic background of chronic fatigue syndrome. Nihon Rinsho. 2007 Jun;65(6):997-1002. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/17561688

 

Viral infections in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a heterogeneous illness in which patients can have different, overlapping signs and symptoms. No single underlying cause has been established for all CFS patients. Epidemiological studies reveal that a flu-like sickness precedes the onset in the majority of cases. The major hypothesis of the pathogenesis of CFS is that infectious agents such as viruses, may trigger and lead to chronic activation of the immune system with abnormal regulation of cytokine production. Many studies have been performed to identify the possible microbial triggers and to understand the epidemiological microbial agents. We have summarized the recent progressive literature of virus, rickettsia, and mycoplasma implicated in the pathogenesis of CFS.

 

Source: Sairenji T, Nagata K. Viral infections in chronic fatigue syndrome. Nihon Rinsho. 2007 Jun;65(6):991-6. [Article in Japanese] https://www.ncbi.nlm.nih.gov/pubmed/17561687

 

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

Abstract:

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.

 

Source: Appel S, Chapman J, Shoenfeld Y. Infection and vaccination in chronic fatigue syndrome: myth or reality? Autoimmunity. 2007 Feb;40(1):48-53. https://www.ncbi.nlm.nih.gov/pubmed/17364497