Tag: review

Altered immune response to exercise in patients with chronic fatigue syndrome/myalgic encephalomyelitis: a systematic literature review

Abstract:

An increasing number of studies have examined how the immune system of patients with Chronic Fatigue Syndrome (CFS), or myalgic encephalomyelitis, responds to exercise. The objective of the present study was to systematically review the scientific literature addressing exercise-induced immunological changes in CFS patients compared to healthy control subjects. A systematic literature search was conducted in the PubMed and Web of science databases using different keyword combinations. We included 23 case control studies that examined whether CFS patients, compared to healthy sedentary controls, have a different immune response to exercise. The included articles were evaluated on their methodological quality.

Compared to the normal response of the immune system to exercise as seen in healthy subjects, patients with CFS have a more pronounced response in the complement system (i.e. C4a split product levels), oxidative stress system (i.e. enhanced oxidative stress combined with a delayed and reduced anti-oxidant response), and an alteration in the immune cells’ gene expression profile (increases in post-exercise interleukin-10 and toll-like receptor 4 gene expression), but not in circulating pro- or anti-inflammatory cytokines. Many of these immune changes relate to post-exertional malaise in CFS, a major characteristic of the illness. The literature review provides level B evidence for an altered immune response to exercise in patients with CFS.

 

Source: Nijs J, Nees A, Paul L, De Kooning M, Ickmans K, Meeus M, Van Oosterwijck J. Altered immune response to exercise in patients with chronic fatigue syndrome/myalgic encephalomyelitis: a systematic literature review. Exerc Immunol Rev. 2014;20:94-116. http://www.medizin.uni-tuebingen.de/transfusionsmedizin/institut/eir/content/2014/94/article.pdf (Full article)

 

Defining recovery in chronic fatigue syndrome: a critical review

Abstract:

PURPOSE: In chronic fatigue syndrome (CFS), the lack of consensus on how recovery should be defined or interpreted has generated controversy and confusion. The purpose of this paper was to systematically review, compare, and evaluate the definitions of recovery reported in the CFS literature and to make recommendations about the scope of recovery assessments.

METHODS: A search was done using the MEDLINE, PubMed, PsycINFO, CINAHL, and Cochrane databases for peer review papers that contained the search terms “chronic fatigue syndrome” and “recovery,” “reversal,” “remission,” and/or “treatment response.”

RESULTS: From the 22 extracted studies, recovery was operationally defined by reference with one or more of these domains: (1) pre-morbid functioning; (2) both fatigue and function; (3) fatigue (or related symptoms) alone; (4) function alone; and/or (5) brief global assessment. Almost all of the studies measuring recovery in CFS did so differently. The brief global assessment was the most common outcome measure used to define recovery. Estimates of recovery ranged from 0 to 66 % in intervention studies and 2.6 to 62 % in naturalistic studies.

CONCLUSIONS: Given that the term “recovery” was often based on limited assessments and less than full restoration of health, other more precise and accurate labels (e.g., clinically significant improvement) may be more appropriate and informative. In keeping with common understandings of the term recovery, we recommend a consistent definition that captures a broad-based return to health with assessments of both fatigue and function as well as the patient’s perceptions of his/her recovery status.

Comment in:

 

Source: Adamowicz JL, Caikauskaite I, Friedberg F. Defining recovery in chronic fatigue syndrome: a critical review. Qual Life Res. 2014 Nov;23(9):2407-16. doi: 10.1007/s11136-014-0705-9. Epub 2014 May 3. https://www.ncbi.nlm.nih.gov/pubmed/24791749

 

Comments

Frank Twisk 2014 Jul 01 11:41 a.m.
A definition of recovery in myalgic encephalomyelitis and chronic fatigue syndrome should be based upon objective measures. Qual Life Res. 2014 Jun 17. doi: 10.1007/s11136-014-0737-1. Twisk FNM.

Abstract

Introduction

Adamowicz and colleagues recently proposed to use “a consistent definition of recovery that captures a broad-based return to health with assessments of both fatigue and function as well as the patients’ perceptions of his/her recovery status” for patients with chronic fatigue syndrome (CFS).

Methods

A qualitative analysis of case definitions for Myalgic encephalomyelitis (ME) and CFS and methods to assess the symptoms and clinical status of ME and CFS patients objectively.

Results

The criteria of CFS define a heterogeneous disorder. ME, often used interchangeably with CFS, is principally defined by muscle weakness, cognitive impairment etc., but above all post-exertional “malaise”: a long-lasting increase in symptoms, e.g. muscle pain and cognitive deficits, after a minor exertion.

The principle symptom of CFS however is “chronic fatigue”. Since post-exertional “malaise” is not obligatory for CFS, only part of the CFS patients meet the diagnostic criteria for ME, while not all ME patients qualify as CFS patients.

There are several accepted methods to assess characteristic symptoms and the clinical status of ME and CFS patients using objective measures, e.g. (repeated) cardiopulmonary exercise tests.

Conclusion

To resolve the debate about the clinical status, proposed effectiveness of therapies and recovery in ME and CFS, it is crucial to accurately diagnose patients using well-defined criteria for ME and CFS and an objective assessment of various typical symptoms, since subjective measures such as “fatigue” will perpetuate the debate.

Comment by Joan Crawford 2014 Jun 04 10:04 a.m. 
Part 2

I’d have liked to have seen this article proposing solid, objective measures be used in the future – ones that have face validity with patients and doctors. Moreover, future trials need to decide if the researchers are aiming at recovery from ill health to as near/close to pre-morbid health (as in like how you’d recover from a severe, debilitating infection) or if they are aim at improving functioning/quality of life as a goal in its own right. This difference ideally should be clearly identified.

The omission of the obvious mathematical/statistical flaws with the use of SF36 PF scale was notable. They miss that using 1SD below mean is not an OK thing to do to compare HC and patients. Doing this is a statistical nonsense. The HC data is massively skewed with a ceiling effect. The bulk of HCs score the max score of 100. (Bowling, 1999, Figure 1). The HC data is not normally distributed so using the mean is not terribly helpful here when comparing and setting standards for recovery. I think using the mode (the value that appears most often in the data sets) would be much more meaningful in this context. Similar will be true of the fatigue scores. There was also no mention of the lowering of the SF36 PF scale outcome measure cut off level in the PACE trial (White et al., 2011). There may well be good reasons for doing so but there was no critical review as to whether the reasons given by White et al were good enough to justify the changes between the proposed pre-trial paper measures (White et al 2007) and the final Lancet one. I notice that White was a co-author of the Knoop (2007) paper that selected a SF36 PF score of -1SD as recovered but in a later trial (White et al., 2011) this was reduced to 60 (-2SD). This is quite a leap by the same investigator.

I particularly do not like their pathologisation/speculation of the role of pre-morbid patient functioning. Action prone nonsense. No one can or are they ever likely to prove objectively that pwME/CFS were overactive/overambitious/action prone before getting ill. I hear people mourning the loss of activities, relationships and careers they cherished and enjoyed immensely. So now they cannot even talk about their pre-illness time without feeling psychologised? To not take a more critical view of this is a real let down for me. It’s subjective, speculative nonsense that is unprovable. Patients have a right to get annoyed when they are psychologised in this manner. It should be rather obvious that patients have ex-work colleagues and friends who worked as hard (or harder, longer, faster) than them who are still employed, with families, fit and well with fulfilling lives. PwME/CFS cannot do this because they are sick. Not because they overdid it a bit. That is burnout, not ME/CFS. I thought it remiss to not see the other side regarding how the impact of this speculation might affect patients. Moreover, there are plenty of not especially ambitious, couch potatoes who are ill!

How recovery in ME/CFS is operationalised in the future requires more critical thought and this must take into account how the patients define recovery and must be able to be demonstrated objectively (Haywood et al., 2011).

References:

Anthony, W. A. (1993) Recovery from mental illness: the guiding vision of the mental health service system in the 1990s. Psychosocial Rehabilitation Journal, 16, 11-23.

Bowling A., Bond, M., Jenkinson, C., & Lamping, D.L. (1999). Short Form 36 (SF-36) Health Survey questionnaire: which normative data should be used? Comparisons between the norms provided by the Omnibus Survey in Britain, the Health Survey for England and the Oxford Healthy Life Survey. Journal of Public Health Medicine. 21(3):255-70.

Haywood, K.L., Staniszewska, S., & Chapman, S. (2011). Quality and acceptability of patient-reported outcome measures used in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): A systematic review. Quality of Life Research, In press.

Knoop, H., Bleijenberg, G., Gielissen, M. F. M., van der Meer, J.W. M., & White, P. D. (2007). Is a full recovery possible after cognitive behavioral therapy for chronic fatigue syndrome? Psychotherapy and Psychosomatics, 76, 171–176.

Lester, H., & Gask, L. (2006). Delivering medical care for patients with serious mental illness or promoting a collaborative model of recovery. British Journal of Psychiatry, 188, 401–402.

White, P.D., Sharpe, M.C., Chalder, T., DeCesare, J.C., Walwyn, R; on behalf of the PACE trial group. (2007). Protocol for the PACE trial: a randomised controlled trial of adaptive pacing, cognitive behaviour therapy, and graded exercise, as supplements to standardised specialist medical care versus standardised specialist medical care alone for patients with the chronic fatigue syndrome/myalgic encephalomyelitis or encephalopathy. BioMed Cent Neurology, 7:6.

White, P.D., Goldsmith, K.A., Johnson, A.L., Potts, L., Walwyn, R., DeCesare, J.C., et al. (2011). Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): A randomised trial. Lancet, 5, 377(9768), 823-836.
Comment by Joan Crawford 2014 Jun 04 10:01 a.m.edited 
Part 1

This paper has a great description of the differences between ‘recovery’ versus ‘adaptation/feeling better’. As a patient I describe this as the difference between ‘feeling better’ and ‘being better’ (i.e. recovered to point comparable with pre-existing health given age increase with ability to return to work/social life without the presence of limiting symptoms). These things appear to get muddled in many clinical trials. I suspect anyone feeling poorly will feel a bit or a lot better after a psychological intervention with a concerned, empathic individual, however, whether this has any impact on their underlying condition or activity levels needs to be shown by objective measures.

It was a disappointment that in this paper there was no push for more objective measures of patient functioning to be used in future research work. For example, pedometers, actigraphy, neuropsychological tests, 2 day exercise testing (if well enough at baseline), using simple dynamometers taking readings over 2 days, return to work/school (or ability to do if the person wished), move from incapacity/sickness welfare payments to job seeking benefits and so on. I’m perplexed when researchers claim that patients are recovered if they continue to receive incapacity/ill health payments. Perhaps in this condition it might be worth measuring whether saliva cortisol levels and NK cell functioning normalise. At a push even the simple 6 minute walking test could be helpful. Objective measures need not be expensive. Simple, reliable and cheap equipment such as pedometers are available for around $30 and can show really well if a patient who is doing better over time. This could be used quite simply to get around the issue of is the patient feeling better because they are actually doing less that is discussed in the review. It’s a shame that straightforward solutions like this were not suggested.

Within the paper the authors refer to Lester & Gask (2006), which includes a popular definition of recovery from within mental health context by William Anthony as: “‘a way of living a satisfying, hopeful and contributing life even with the limitations caused by illness. Recovery involves the development of a new meaning and purpose in one’s life as one grows beyond the catastrophic effects of mental illness’ (Antony, 1993: p. 21). I had not seen this definition before for recovery so it was educating to be made aware that this was a widely used concept. To me that defines adaptation, not recovery. I would not be happy with researchers who decided that that was a good place to start defining recovery from ME/CFS. I’d want the goal to be at a minimum to not feel ill or sick or debilitated and able to be free of disease symptoms and normal functioning for the patient for their age.

References and Part 2 above

Assessing severity of illness and outcomes of treatment in children with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME): a systematic review of patient-reported outcome measures (PROMs)

Abstract:

Chronic Fatigue Syndrome or Myalgic Encephalomyelitis (CFS/ME) in children is characterized by persistent or recurrent debilitating fatigue which results in a substantial reduction in activity. There is a growing interest in the use of questionnaires, or patient-reported outcome measures (PROMs), to assess how patients function and feel in relation to their health and associated healthcare. However, guidance for PROM selection for children with CFS/ME does not exist.

We reviewed the quality and acceptability of PROMs used with children with CFS/ME to inform recommendations for practice. We conducted a systematic review of PROMs completed by children with CFS/ME. The quality of the evaluative studies and the reviewed measures were assessed against recommended criteria using an appraisal framework and the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. We sought evidence of measurement (reliability, validity, responsiveness, interpretability, data quality) and practical properties (acceptability, relevance, feasibility).

Sixteen articles were included in the review, providing evidence of reliability and/or validity for 13 PROMs. Of these, five were child-specific (one health-related quality-of-life; four emotional well-being) and eight were not (four emotional well-being, three fatigue-specific; and one generic). All measures had limited evidence of measurement properties and no evidence of practical properties.

Recommendations for patient-reported assessment are difficult to make because of limited evidence of the quality and acceptability of PROMs for children with CFS/ME. The appraisal method highlighted significant methodological and quality issues which must be addressed in future research. There is a lack of qualitative evidence describing the outcomes of healthcare that are important to children with CFS/ME, and the relevance or appropriateness of available measures.

Future PROM development and evaluation in this group must seek to involve children collaboratively to ensure that the outcomes that children care about are assessed in an acceptable way.

© 2014 John Wiley & Sons Ltd.

 

Source: Haywood KL, Collin SM, Crawley E. Assessing severity of illness and outcomes of treatment in children with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME): a systematic review of patient-reported outcome measures (PROMs). Child Care Health Dev. 2014 Nov;40(6):806-24. doi: 10.1111/cch.12135. Epub 2014 Mar 24. https://www.ncbi.nlm.nih.gov/pubmed/24661148

 

Overcoming the barriers to the diagnosis and management of chronic fatigue syndrome/ME in primary care: a meta synthesis of qualitative studies

Abstract:

BACKGROUND: The NICE guideline for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) emphasises the need for an early diagnosis in primary care with management tailored to patient needs. However, GPs can be reluctant to make a diagnosis and are unsure how to manage people with the condition.

METHODS: A meta synthesis of published qualitative studies was conducted, producing a multi-perspective description of barriers to the diagnosis and management of CFS/ME, and the ways that some health professionals have been able to overcome them. Analysis provided second-order interpretation of the original findings and developed third-order constructs to provide recommendations for the medical curriculum.

RESULTS: Twenty one qualitative studies were identified. The literature shows that for over 20 years health professionals have reported a limited understanding of CFS/ME. Working within the framework of the biomedical model has also led some GPs to be sceptical about the existence of the condition. GPs who provide a diagnosis tend to have a broader, multifactorial, model of the condition and more positive attitudes towards CFS/ME. These GPs collaborate with patients to reach agreement on symptom management, and use their therapeutic skills to promote self care.

CONCLUSIONS: In order to address barriers to the diagnosis and management of CFS/ME in primary care, the limitations of the biomedical model needs to be recognised. A more flexible bio-psychosocial approach is recommended where medical school training aims to equip practitioners with the skills needed to understand, support and manage patients and provide a pathway to refer for specialist input.

 

Source: Bayliss K, Goodall M, Chisholm A, Fordham B, Chew-Graham C, Riste L, Fisher L, Lovell K, Peters S, Wearden A. Overcoming the barriers to the diagnosis and management of chronic fatigue syndrome/ME in primary care: a meta synthesis of qualitative studies. BMC Fam Pract. 2014 Mar 7;15:44. doi: 10.1186/1471-2296-15-44. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3973969/ (Full article)

 

Malfunctioning of the autonomic nervous system in patients with chronic fatigue syndrome: a systematic literature review

Abstract:

INTRODUCTION: It is hypothesised that the autonomic nervous system responds differently to various stressors in patients with chronic fatigue syndrome (CFS) compared with healthy controls. The goal is to systematically review the scientific literature addressing the functioning of the autonomic nervous system in patients with CFS.

MATERIALS AND METHODS: All studies that were identified through electronic databases (PubMed and Web of Science) were screened for eligibility based on the selection criteria and assessed (two independent raters) for methodological quality using a methodological checklist for case-control studies.

RESULTS: Twenty-seven case-control studies were included. The methodological quality varied between 50% and 71·4%. Some studies showed different responses to head-up tilt and other autonomous testing.

CONCLUSION: Although comparison between the included case-control studies was difficult, we can conclude that there are differences in autonomous response between patients with CFS and healthy controls. The heart rate dynamic response during the head-up tilt test differs between patients with CFS and healthy controls, supporting the increased prevalence of postural orthostatic tachycardia syndrome. The autonomic response can be useful for the diagnosis of CFS.

© 2014 Stichting European Society for Clinical Investigation Journal Foundation.

 

Source: Van Cauwenbergh D, Nijs J, Kos D, Van Weijnen L, Struyf F, Meeus M. Malfunctioning of the autonomic nervous system in patients with chronic fatigue syndrome: a systematic literature review. Eur J Clin Invest. 2014 May;44(5):516-26. doi: 10.1111/eci.12256. https://www.ncbi.nlm.nih.gov/pubmed/24601948

 

Mitochondrial dysfunctions in myalgic encephalomyelitis/chronic fatigue syndrome explained by activated immuno-inflammatory, oxidative and nitrosative stress pathways

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) is classified by the World Health Organization as a disorder of the central nervous system. ME/cfs is an neuro-immune disorder accompanied by chronic low-grade inflammation, increased levels of oxidative and nitrosative stress (O&NS), O&NS-mediated damage to fatty acids, DNA and proteins, autoimmune reactions directed against neoantigens and brain disorders. Mitochondrial dysfunctions have been found in ME/cfs, e.g. lowered ATP production, impaired oxidative phosphorylation and mitochondrial damage.

This paper reviews the pathways that may explain mitochondrial dysfunctions in ME/cfs. Increased levels of pro-inflammatory cytokines, such as interleukin-1 and tumor necrosis factor-α, and elastase, and increased O&NS may inhibit mitochondrial respiration, decrease the activities of the electron transport chain and mitochondrial membrane potential, increase mitochondrial membrane permeability, interfere with ATP production and cause mitochondrial shutdown. The activated O&NS pathways may additionally lead to damage of mitochondrial DNA and membranes thus decreasing membrane fluidity. Lowered levels of antioxidants, zinc and coenzyme Q10, and ω3 polyunsaturated fatty acids in ME/cfs may further aggravate the activated immuno-inflammatory and O&NS pathways.

Therefore, it may be concluded that immuno-inflammatory and O&NS pathways may play a role in the mitochondrial dysfunctions and consequently the bioenergetic abnormalities seen in patients with ME/cfs. Defects in ATP production and the electron transport complex, in turn, are associated with an elevated production of superoxide and hydrogen peroxide in mitochondria creating adaptive and synergistic damage.

It is argued that mitochondrial dysfunctions, e.g. lowered ATP production, may play a role in the onset of ME/cfs symptoms, e.g. fatigue and post exertional malaise, and may explain in part the central metabolic abnormalities observed in ME/cfs, e.g. glucose hypometabolism and cerebral hypoperfusion.

 

Source: Morris G, Maes M. Mitochondrial dysfunctions in myalgic encephalomyelitis/chronic fatigue syndrome explained by activated immuno-inflammatory, oxidative and nitrosative stress pathways. Metab Brain Dis. 2014 Mar;29(1):19-36. doi: 10.1007/s11011-013-9435-x. Epub 2013 Sep 10.https://www.ncbi.nlm.nih.gov/pubmed/24557875

 

Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review

Abstract:

OBJECTIVE: To identify case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), and explore how the validity of case definitions can be evaluated in the absence of a reference standard.

DESIGN: Systematic review.

SETTING: International.

PARTICIPANTS: A literature search, updated as of November 2013, led to the identification of 20 case definitions and inclusion of 38 validation studies.

PRIMARY AND SECONDARY OUTCOME MEASURE: Validation studies were assessed for risk of bias and categorised according to three validation models: (1) independent application of several case definitions on the same population, (2) sequential application of different case definitions on patients diagnosed with CFS/ME with one set of diagnostic criteria or (3) comparison of prevalence estimates from different case definitions applied on different populations.

RESULTS: A total of 38 studies contributed data of sufficient quality and consistency for evaluation of validity, with CDC-1994/Fukuda as the most frequently applied case definition. No study rigorously assessed the reproducibility or feasibility of case definitions. Validation studies were small with methodological weaknesses and inconsistent results. No empirical data indicated that any case definition specifically identified patients with a neuroimmunological condition.

CONCLUSIONS: Classification of patients according to severity and symptom patterns, aiming to predict prognosis or effectiveness of therapy, seems useful. Development of further case definitions of CFS/ME should be given a low priority. Consistency in research can be achieved by applying diagnostic criteria that have been subjected to systematic evaluation.

 

Source: Brurberg KG, Fønhus MS, Larun L, Flottorp S, Malterud K. Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review. BMJ Open. 2014 Feb 7;4(2):e003973. doi: 10.1136/bmjopen-2013-003973. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918975/ (Full article)

 

Chronic fatigue syndrome: a personalized integrative medicine approach

Abstract:

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a relatively common illness, yet despite considerable investigation, current treatments have modest benefits, and the prognosis remains poor. Because CFS/ME is a heterogeneous disorder with diverse etiological factors and pathological features, a patient-centered integrative framework based on modifiable physiological and environmental factors may offer hope for more effective management and better clinical outcomes. An individualized approach may also help target interventions for subgroups most likely to respond to specific treatments. This review summarizes a number of avenues for integrative management, including dietary modification, functional nutritional deficiencies, physical fitness, psychological and physical stress, environmental toxicity, gastrointestinal disturbances, immunological aberrations, inflammation, oxidative stress, and mitochondrial dysfunction. A personalized, integrative approach to CFS/ME deserves further consideration as a template for patient management and future research.

 

Source: Brown B. Chronic fatigue syndrome: a personalized integrative medicine approach. Altern Ther Health Med. 2014 Jan-Feb;20(1):29-40. https://www.ncbi.nlm.nih.gov/pubmed/24445354

 

Chronic Fatigue Syndrome: Case Definitions and Diagnostic Assessment

Abstract:

Chronic fatigue syndrome (CFS) is a chronic, debilitating illness that has posed considerable challenges for both patients and health care providers. Individuals with CFS often deal with considerable stigma and difficulties accessing appropriate care. Many medical professionals are increasingly recognizing the devastating nature of this illness, but at this time, few health care workers are knowledgeable and experienced enough to provide adequate patient care. There is a need for further efforts to educate health care workers on CFS diagnostic, assessment, and treatment issues. The present article reviews controversies regarding CFS case definitions, diagnostic criteria, the name of the illness, and epidemiological and treatment studies. We conclude that an imprecise case definition underlies many of the problems with diagnostic and treatment issues.

 

Source: Williams YJ, Jantke RL, Jason LA. Chronic Fatigue Syndrome: Case Definitions and Diagnostic Assessment. N Y State Psychol. 2014 Winter;26(4):41-45. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5008849/ (Full article)

 

Natural killer cells in patients with severe chronic fatigue syndrome

Abstract:

Maintenance of health and physiological homeostasis is a synergistic process involving tight regulation of proteins, transcription factors and other molecular processes. The immune system consists of innate and adaptive immune cells that are required to sustain immunity. The presence of pathogens and tumour cells activates innate immune cells, in particular Natural Killer (NK) cells.

Stochastic expression of NK receptors activates either inhibitory or activating signals and results in cytokine production and activation of pathways that result in apoptosis of target cells. Thus, NK cells are a necessary component of the immunological process and aberrations in their functional processes, including equivocal levels of NK cells and cytotoxic activity pre-empts recurrent viral infections, autoimmune diseases and altered inflammatory responses. NK cells are implicated in a number of diseases including chronic fatigue syndrome (CFS). The purpose of this review is to highlight the different profiles of NK cells reported in CFS patients and to determine the extent of NK immune dysfunction in subtypes of CFS patients based on severity in symptoms.

 

Source: Brenu EW, Hardcastle SL, Atkinson GM, van Driel ML, Kreijkamp-Kaspers S, Ashton KJ, Staines DR, Marshall-Gradisnik SM. Natural killer cells in patients with severe chronic fatigue syndrome. Auto Immun Highlights. 2013 Apr 16;4(3):69-80. doi: 10.1007/s13317-013-0051-x. ECollection 2013. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4389023/ (Full article)