Dysregulation of cytokine pathways in chronic fatigue syndrome and multiple sclerosis

Abstract:

Background: Cytokine studies in chronic fatigue syndrome (CFS) have yielded mixed findings.

Purpose: This investigation evaluated whether network analysis of cytokine production differs between patients with CFS and multiple sclerosis (MS) as compared to a reference group of healthy controls.

Methods: Three subgroups (N = 109) were included: 15 participants who met diagnostic criteria for CFS, 57 participants meeting criteria for MS, and 37 controls. Peripheral blood was obtained and production of a select cytokine profile was determined from stimulated and unstimulated mononuclear cells. Data were generated through the use of a multi-analyte bead suspension array. Pairwise associations were determined for each group, and these associations were used to create a graphical representation of the data. The graph was clustered using an eigenvector community algorithm and results visualized using edges to model the correlations by color and thickness to show direction and strength.

Results: The control and MS groups produced a three-neighborhood relationship regardless of cell condition. While producing a three-neighborhood relationship, the MS group differed significantly from the control group as it displayed stronger relationships among pro-inflammatory cytokines. In contrast, the CFS group displayed a three-neighborhood solution when unstimulated. However, when cells from the CFS group were stimulated, a two-neighborhood model was found that exhibited stronger inter-cytokine correlations. The model found in CFS was significantly different from that found in the control and MS groups.

Conclusion: CFS was characterized by a pattern of global immunologic activation using network analysis, fundamentally different from those found for either MS or control groups.

Source: Matthew Sorenson, Jacob Furst, Herbert Mathews & Leonard A. Jason. Dysregulation of cytokine pathways in chronic fatigue syndrome and multiple sclerosis. Fatigue: Biomedicine, Health & Behavior, Published online: 07 Jun 2017. http://www.tandfonline.com/doi/abs/10.1080/21641846.2017.1335237?journalCode=rftg20

The role of IP-10 in Chronic Fatigue Syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a severely debilitating and complex illness of uncertain cause, characterised by prolonged, fatigue triggered by minimal activity. There is evidence that CFS is associated with chronic inflammation. Studies have shown that plasma levels of cytokines are chronically modified in patients with CFS.

This study examined physiological, subjective and cognitive factors associated with plasma cytokine concentrations in a cohort of 92 patients compared with age and sex matched healthy controls. A sub-group of patients and healthy controls (HCs) also underwent more detailed analyses of muscle function, cytokine production and cognitive function. Patients were diagnosed with CFS if they met the Oxford criteria for Chronic Fatigue Syndrome and recommended NICE guidelines. Patients completed a number of validated questionnaires including the Chalder Fatigue Questionnaire (CFQ) which is considered a valid and reliable measure of fatigue in patients with CFS.

Patients with CFS demonstrated a characteristic significant reduction in Maximal Voluntary Contraction Force compared with HCs. Data on plasma concentrations of 27 pro- and anti-inflammatory cytokines were analysed using multiple or logistic regression with age and sex which were significant covariates included in each model. CFS was strongly associated with a limited number of cytokines. Diagnosis of CFS was associated with increased plasma contents of MIP-1a, MIP-1b and RANTES (p<0.05) and marginally with Eotaxin (p=0.07) when modelled individually. MVC and self-reported fatigue both showed particularly strong associations with plasma IP-10 concentrations.

Muscle content of IP-10 mRNA was significantly elevated, suggesting that, at least in part, muscle was a source of this IP-10 but not the other cytokines. Pairwise associations between MVC and cytokines demonstrated that the reduced MVC seen in patients with CFS was strongly associated with plasma levels of IP-10, TNF-α and IL-5. Further analyses revealed strong correlations between plasma RANTES and eotaxin levels and poorer verbal recall and RTs of patients with CFS. The consistent association of IP-10 with the physiological features and of RANTES and eotaxin with the cognitive features of CFS provides compelling evidence for a role of these cytokine/chemokines in the physiological and cognitive pathology of CFS.

This work was funded by the Medical Research Council.

Source: Anne McArdle, Arief Gusnanto, Kate Earl, George Sakellariou, Clare Lawton, Daniel Owens, Graeme Close, Michael Beadsworth and Louise Dye. The role of IP-10 in Chronic Fatigue Syndrome. April 2017, The FASEB Journal, vol. 31 no. 1 Supplement lb789. http://www.fasebj.org/content/31/1_Supplement/lb789.short

 

A systematic review of the association between fatigue and genetic polymorphisms

Abstract:

Fatigue is one of the most common and distressing symptoms, leading to markedly decreased quality of life among a large subset of patients with a variety of disorders. Susceptibility to fatigue may be influenced by genetic factors including single nucleotide polymorphisms (SNPs), especially in the regulatory regions, of relevant genes.

To further investigate the association of SNPs with fatigue in various patient populations, a systematic search was conducted on Pubmed, CINAHL, PsycINFO, and Sociological Abstracts Database for fatigue related-terms in combination with polymorphisms or genetic variation-related terms. Fifty papers in total met the inclusion and exclusion criteria for this analysis. These 50 papers were further classified into three subgroups for evaluation: chronic fatigue syndrome (CFS), cancer-related fatigue (CRF) and other disease-related fatigue.

SNPs in regulatory pathways of immune and neurotransmitter systems were found to play important roles in the etiologies of CFS, CRF and other disease-related fatigue. Evidence for associations between elevated fatigue and specific polymorphisms in TNFα, IL1b, IL4 and IL6 genes was revealed for all three subgroups of fatigue.

We also found CFS shared a series of polymorphisms in HLA, IFN-γ, 5-HT and NR3C1 genes with other disease-related fatigue, however these SNPs (excluding IFN-γ) were not found to be adequately investigated in CRF. Gaps in knowledge related to fatigue etiology and recommendations for future research are further discussed.

Copyright © 2017 Elsevier Inc. All rights reserved.

 

Source: Wang T, Yin J, Miller AH, Xiao C. A systematic review of the association between fatigue and genetic polymorphisms. Brain Behav Immun. 2017 Jan 12. pii: S0889-1591(17)30007-7. doi: 10.1016/j.bbi.2017.01.007. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28089639

 

Illness progression in chronic fatigue syndrome: a shifting immune baseline

Abstract:

BACKGROUND: Validation of biomarkers for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) across data sets has proven disappointing. As immune signature may be affected by many factors, our objective was to explore the shift in discriminatory cytokines across ME/CFS subjects separated by duration of illness.

METHODS: Cytokine expression collected at rest across multiple studies for female ME/CFS subjects (i) 18 years or younger, ill for 2 years or less (n = 18), (ii) 18-50 years of age, ill for 7 years (n = 22), and (iii) age 50 years or older (n = 28), ill for 11 years on average. Control subjects were matched for age and body mass index (BMI). Data describing the levels of 16 cytokines using a chemiluminescent assay was used to support the identification of separate linear classification models for each subgroup. In order to isolate the effects of duration of illness alone, cytokines that changed significantly with age in the healthy control subjects were excluded a priori.

RESULTS: Optimal selection of cytokines in each group resulted in subsets of IL-1α, 6, 8, 15 and TNFα. Common to any 2 of 3 groups were IL-1α, 6 and 8. Setting these 3 markers as a triple screen and adjusting their contribution according to illness duration sub-groups produced ME/CFS classification accuracies of 75-88 %. The contribution of IL-1α, higher in recently ill adolescent ME/CFS subjects was progressively less important with duration. While high levels of IL-8 screened positive for ME/CFS in the recently afflicted, the opposite was true for subjects ill for more than 2 years. Similarly, while low levels of IL-6 suggested early ME/CFS, the reverse was true in subjects over 18 years of age ill for more than 2 years.

CONCLUSIONS: These preliminary results suggest that IL-1α, 6 and 8 adjusted for illness duration may serve as robust biomarkers, independent of age, in screening for ME/CFS.

 

Source: Russell L, Broderick G, Taylor R, Fernandes H, Harvey J, Barnes Z, Smylie A, Collado F, Balbin EG, Katz BZ, Klimas NG, Fletcher MA. Illness progression in chronic fatigue syndrome: a shifting immune baseline. BMC Immunol. 2016 Mar 10;17:3. doi: 10.1186/s12865-016-0142-3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785654/ (Full article)

 

Reductions in circulating levels of IL-16, IL-7 and VEGF-A in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Recently, differences in the levels of various chemokines and cytokines were reported in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as compared with controls. Moreover, the analyte profile differed between chronic ME/CFS patients of long duration versus patients with disease of less than 3 years. In the current study, we measured the plasma levels of 34 cytokines, chemokines and growth factors in 100 chronic ME/CFS patients of long duration and in 79 gender and age-matched controls.

We observed highly significant reductions in the concentration of circulating interleukin (IL)-16, IL-7, and Vascular Endothelial Growth Factor A (VEGF-A) in ME/CFS patients. All three biomarkers were significantly correlated in a multivariate cluster analysis. In addition, we identified significant reductions in the concentrations of fractalkine (CX3CL1) and monokine-induced-by-IFN-γ (MIG; CXCL9) along with increases in the concentrations of eotaxin 2 (CCL24) in ME/CFS patients.

Our data recapitulates previous data from another USA ME/CFS cohort in which circulating levels of IL-7 were reduced. Also, a reduced level of VEGF-A was reported previously in sera of patients with Gulf War Illness as well as in cerebral spinal fluid samples from a different cohort of USA ME/CFS patients.

To our knowledge, we are the first to test for levels of IL-16 in ME/CFS patients. In combination with previous data, our work suggests that the clustered reduction of IL-7, IL-16 and VEGF-A may have physiological relevance to ME/CFS disease. This profile is ME/CFS-specific since measurement of the same analytes present in chronic infectious and autoimmune liver diseases, where persistent fatigue is also a major symptom, failed to demonstrate the same changes. Further studies of other ME/CFS and overlapping disease cohorts are warranted in future.

Copyright © 2015 Elsevier Ltd. All rights reserved.

 

Source: Landi A, Broadhurst D, Vernon SD, Tyrrell DL, Houghton M. Reductions in circulating levels of IL-16, IL-7 and VEGF-A in myalgic encephalomyelitis/chronic fatigue syndrome. Cytokine. 2016 Feb;78:27-36. doi: 10.1016/j.cyto.2015.11.018. Epub 2015 Nov 28. https://www.ncbi.nlm.nih.gov/pubmed/26615570

 

Serum Immune Proteins in Moderate and Severe Chronic Fatigue Syndrome/Myalgic Encephalomyelitis Patients

Abstract:

Immunological dysregulation is present in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), with recent studies also highlighting the importance of examining symptom severity. This research addressed this relationship between CFS/ME severity subgroups, assessing serum immunoglobulins and serum cytokines in severe and moderate CFS/ME patients.

Participants included healthy controls (n= 22), moderately (n = 22) and severely (n=19) affected CFS/ME patients. The 1994 Fukuda Criteria defined CFS/ME and severity scales confirmed mobile and housebound CFS/ME patients as moderate and severe respectively.

IL-1β was significantly reduced in severe compared with moderate CFS/ME patients. IL-6 was significantly decreased in moderate CFS/ME patients compared with healthy controls and severe CFS/ME patients. RANTES was significantly increased in moderate CFS/ME patients compared to severe CFS/ME patients. Serum IL-7 and IL-8 were significantly higher in the severe CFS/ME group compared with healthy controls and moderate CFS/ME patients. IFN-γ was significantly increased in severe CFS/ME patients compared with moderately affected patients.

This was the first study to show cytokine variation in moderate and severe CFS/ME patients, with significant differences shown between CFS/ME symptom severity groups. This research suggests that distinguishing severity subgroups in CFS/ME research settings may allow for a more stringent analysis of the heterogeneous and otherwise inconsistent illness.

Source: Hardcastle SL, Brenu EW, Johnston S, Nguyen T, Huth T, Ramos S, Staines D, Marshall-Gradisnik S. Serum Immune Proteins in Moderate and Severe Chronic Fatigue Syndrome/Myalgic Encephalomyelitis Patients. Int J Med Sci. 2015 Sep 5;12(10):764-72. doi: 10.7150/ijms.12399. ECollection 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4615236/ (Full article)

 

Distinct plasma immune signatures in ME/CFS are present early in the course of illness

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an unexplained incapacitating illness that may affect up to 4 million people in the United States alone. There are no validated laboratory tests for diagnosis or management despite global efforts to find biomarkers of disease. We considered the possibility that inability to identify such biomarkers reflected variations in diagnostic criteria and laboratory methods as well as the timing of sample collection during the course of the illness.

Accordingly, we leveraged two large, multicenter cohort studies of ME/CFS to assess the relationship of immune signatures with diagnosis, illness duration, and other clinical variables. Controls were frequency-matched on key variables known to affect immune status, including season of sampling and geographic site, in addition to age and sex. We report here distinct alterations in plasma immune signatures early in the course of ME/CFS (n = 52) relative to healthy controls (n = 348) that are not present in subjects with longer duration of illness (n = 246).

Analyses based on disease duration revealed that early ME/CFS cases had a prominent activation of both pro- and anti-inflammatory cytokines as well as dissociation of intercytokine regulatory networks. We found a stronger correlation of cytokine alterations with illness duration than with measures of illness severity, suggesting that the immunopathology of ME/CFS is not static. These findings have critical implications for discovery of interventional strategies and early diagnosis of ME/CFS.

 

Source: Hornig M, Montoya JG, Klimas NG, Levine S, Felsenstein D, Bateman L, Peterson DL, Gottschalk CG, Schultz AF, Che X, Eddy ML, Komaroff AL, Lipkin WI. Distinct plasma immune signatures in ME/CFS are present early in the course of illness. Sci Adv. 2015 Feb;1(1). pii: e1400121. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4465185/ (Full article)

 

Cytokines in the cerebrospinal fluids of patients with chronic fatigue syndrome/myalgic encephalomyelitis

Abstract:

OBJECTIVES: Previous research has provided evidence for dysregulation in peripheral cytokines in patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). To date only one study has examined cytokines in cerebrospinal fluid (CSF) samples of CFS/ME patients. The purpose of this pilot study was to examine the role of cytokines in CSF of CFS/ME patients.

METHODS: CSF was collected from 18 CFS/ME patients and 5 healthy controls. The CSF samples were examined for the expression of 27 cytokines (interleukin- (IL-) 1β, IL-1ra, IL-2, IL-4, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12p70, IL-13, IL-15, IL-17, basic FGF, eotaxin, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1 (MCAF), MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α, and VEGF) using the Bio-Plex Human Cytokine 27-plex Assay.

RESULTS: Of the 27 cytokines examined, only IL-10 was significantly reduced in the CFS/ME patients in comparison to the controls.

CONCLUSIONS: This preliminary investigation suggests that perturbations in inflammatory cytokines in the CSF of CFS/ME patients may contribute to the neurological discrepancies observed in CFS/ME.

 

Source: Peterson D, Brenu EW, Gottschalk G, Ramos S, Nguyen T, Staines D, Marshall-Gradisnik S. Cytokines in the cerebrospinal fluids of patients with chronic fatigue syndrome/myalgic encephalomyelitis. Mediators Inflamm. 2015;2015:929720. doi: 10.1155/2015/929720. Epub 2015 Mar 5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4365360/ (Full article)

 

Cytokine network analysis of cerebrospinal fluid in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome is an unexplained debilitating disorder that is frequently associated with cognitive and motor dysfunction. We analyzed cerebrospinal fluid from 32 cases, 40 subjects with multiple sclerosis and 19 normal subjects frequency-matched for age and sex using a 51-plex cytokine assay.

Group-specific differences were found for the majority of analytes with an increase in cases of CCL11 (eotaxin), a chemokine involved in eosinophil recruitment. Network analysis revealed an inverse relationship between interleukin 1 receptor antagonist and colony-stimulating factor 1, colony-stimulating factor 2 and interleukin 17F, without effects on interleukin 1α or interleukin 1β, suggesting a disturbance in interleukin 1 signaling.

Our results indicate a markedly disturbed immune signature in the cerebrospinal fluid of cases that is consistent with immune activation in the central nervous system, and a shift toward an allergic or T helper type-2 pattern associated with autoimmunity.

 

Source: Hornig M, Gottschalk G, Peterson DL, Knox KK, Schultz AF, Eddy ML, Che X, Lipkin WI. Cytokine network analysis of cerebrospinal fluid in myalgic encephalomyelitis/chronic fatigue syndrome. Mol Psychiatry. 2016 Feb;21(2):261-9. doi: 10.1038/mp.2015.29. Epub 2015 Mar 31. https://www.ncbi.nlm.nih.gov/pubmed/25824300

 

Plasma cytokine expression in adolescent chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a prevalent and disabling condition among adolescents. The pathophysiology is poorly understood, but low-grade systemic inflammation has been suggested as an important component. This study compared circulating levels of individual cytokines and parameters of cytokine networks in a large set of adolescent CFS patients and healthy controls, and explored associations between cytokines and symptoms in the CFS group.

CFS patients (12-18years old) were recruited nation-wide to a single referral center as part of the NorCAPITAL project (ClinicalTrials ID: NCT01040429). A broad case definition of CFS was applied, requiring three months of unexplained, disabling chronic/relapsing fatigue of new onset, whereas no accompanying symptoms were necessary. Thus, the case definition was broader than the Fukuda-criteria of CFS. Healthy controls having comparable distribution of gender and age were recruited from local schools. Twenty-seven plasma cytokines, including interleukins, chemokines and growth factors were assayed using multiplex technology. The results were subjected to network analyses using the ARACNE algorithm. Symptoms were charted by a questionnaire, and patients were subgrouped according to the Fukuda-criteria. A total of 120 CFS patients and 68 healthy controls were included.

CFS patients had higher scores for fatigue (p<0.001) and inflammatory symptoms (p<0.001) than healthy controls. All cytokine levels and cytokine network parameters were similar, and none of the differences were statistically different across the two groups, also when adjusting for adherence to the Fukuda criteria of CFS. Within the CFS group, there were no associations between aggregate cytokine network parameters and symptom scores. Adolescent CFS patients are burdened by symptoms that might suggest low-grade systemic inflammation, but plasma levels of individual cytokines as well as cytokine network measures were not different from healthy controls, and there were no associations between symptoms and cytokine expression in the CFS group. Low-grade systemic inflammation does not appear to be a central part of adolescent CFS pathophysiology.

Copyright © 2014 Elsevier Inc. All rights reserved.

 

Source: Wyller VB, Sørensen Ø, Sulheim D, Fagermoen E, Ueland T, Mollnes TE. Plasma cytokine expression in adolescent chronic fatigue syndrome. Brain Behav Immun. 2015 May;46:80-6. doi: 10.1016/j.bbi.2014.12.025. Epub 2014 Dec 31. https://www.ncbi.nlm.nih.gov/pubmed/25555530