Genetic association study in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) identifies several potential risk loci

Highlights:

• Largest ME/CFS genetic study to date.

• Three different cohorts totaling >2500 patients.

• First Immunochip study in ME/CFS.

• Possible implication of TPPP genetic region.

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disease of unknown etiology and pathogenesis, which manifests in a variety of symptoms like post-exertional malaise, brain fog, fatigue and pain. Hereditability is suggested by an increased disease risk in relatives, however, genome-wide association studies in ME/CFS have been limited by small sample sizes and broad diagnostic criteria, therefore no established risk loci exist to date.

In this study, we have analyzed three ME/CFS cohorts: a Norwegian discovery cohort (N = 427), a Danish replication cohort (N = 460) and a replication dataset from the UK biobank (N = 2105). To the best of our knowledge, this is the first ME/CFS genome-wide association study of this magnitude incorporating 2532 patients for the genome-wide analyses and 460 patients for a targeted analysis. Even so, we did not find any ME/CFS risk loci displaying genome-wide significance.

In the Norwegian discovery cohort, the TPPP gene region showed the most significant association (rs115523291, P = 8.5 × 10−7), but we could not replicate the top SNP. However, several other SNPs in the TPPP gene identified in the Norwegian discovery cohort showed modest association signals in the self-reported UK biobank CFS cohort, which was also present in the combined analysis of the Norwegian and UK biobank cohorts, TPPP (rs139264145; P = 0.00004). Interestingly, TPPP is expressed in brain tissues, hence it will be interesting to see whether this association, with time, will be verified in even larger cohorts. Taken together our study, despite being the largest to date, could not establish any ME/CFS risk loci, but comprises data for future studies to accumulate the power needed to reach genome-wide significance.

Source: Hajdarevic R, Lande A, Mehlsen J, Rydland A, Sosa DD, Strand EB, Mella O, Pociot F, Fluge Ø, Lie BA, Viken MK. Genetic association study in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) identifies several potential risk loci. Brain Behav Immun. 2022 Mar 19:S0889-1591(22)00078-2. doi: 10.1016/j.bbi.2022.03.010. Epub ahead of print. PMID: 35318112. https://www.sciencedirect.com/science/article/pii/S0889159122000782 (Full study)

Impact of Long-Term Cryopreservation on Blood Immune Cell Markers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Implications for Biomarker Discovery

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex neuroimmune disorder characterized by numerous symptoms of unknown etiology. The ME/CFS immune markers reported so far have failed to generate a clinical consensus, perhaps partly due to the limitations of biospecimen biobanking. To address this issue, we performed a comparative analysis of the impact of long-term biobanking on previously identified immune markers and also explored additional potential immune markers linked to infection in ME/CFS.

A correlation analysis of marker cryostability across immune cell subsets based on flow cytometry immunophenotyping of fresh blood and frozen PBMC samples collected from individuals with ME/CFS (n = 18) and matched healthy controls (n = 18) was performed. The functionality of biobanked samples was assessed on the basis of cytokine production assay after stimulation of frozen PBMCs. T cell markers defining Treg subsets and the expression of surface glycoprotein CD56 in T cells and the frequency of the effector CD8 T cells, together with CD57 expression in NK cells, appeared unaltered by biobanking. By contrast, NK cell markers CD25 and CD69 were notably increased, and NKp46 expression markedly reduced, by long-term cryopreservation and thawing. Further exploration of Treg and NK cell subsets failed to identify significant differences between ME/CFS patients and healthy controls in terms of biobanked PBMCs.

Our findings show that some of the previously identified immune markers in T and NK cell subsets become unstable after cell biobanking, thus limiting their use in further immunophenotyping studies for ME/CFS. These data are potentially relevant for future multisite intervention studies and cooperative projects for biomarker discovery using ME/CFS biobanked samples. Further studies are needed to develop novel tools for the assessment of biomarker stability in cryopreserved immune cells from people with ME/CFS.

Source: Gómez-Mora E, Carrillo J, Urrea V, Rigau J, Alegre J, Cabrera C, Oltra E, Castro-Marrero J, Blanco J. Impact of Long-Term Cryopreservation on Blood Immune Cell Markers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Implications for Biomarker Discovery. Front Immunol. 2020 Nov 17;11:582330. doi: 10.3389/fimmu.2020.582330. PMID: 33329554; PMCID: PMC7732598. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7732598/  (Full text)

The UK ME/CFS Biobank: A Disease-Specific Biobank for Advancing Clinical Research Into Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling disease characterized by unexplained incapacitating fatigue, accompanied by variable multi-systemic symptoms. ME/CFS causes a significant personal and public health burden, and urgently requires the coordination of research efforts to investigate its etiology and pathophysiology and to develop and validate sensitive and specific biomarkers to confirm diagnosis.

This narrative paper describes how people with ME/CFS, together with a multidisciplinary team of researchers, have established the UK ME/CFS Biobank (UKMEB), a unique research infrastructure specifically designed to expedite biomedical research into ME/CFS. We describe the journey that led to its conceptualization and operation, and how the resource has served as a model disease-specific biobank, aggregating human biospecimens alongside comprehensive health information on participants.

The UKMEB currently has data and samples from 600 donors including people with ME/CFS and a comparison group with multiple sclerosis and healthy controls. A longitudinal sub-cohort has been established of participants having follow-up assessments at multiple time-points. As an open resource for quality and ethical research into ME/CFS, biological samples and data have not only been analyzed within our research team but have also been shared with researchers across Europe, America and the Middle East. We continue to encourage researchers from academic and commercial sectors to access the UKMEB. Major steps have been taken and challenges remain; these include sustainability and expansion, and harmonization of processes to facilitate integration with other bioresources and databanks internationally.

Source: Lacerda EM, Mudie K, Kingdon CC, Butterworth JD, O’Boyle S, Nacul L. The UK ME/CFS Biobank: A Disease-Specific Biobank for Advancing Clinical Research Into Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Front Neurol. 2018 Dec 4;9:1026. doi: 10.3389/fneur.2018.01026.
eCollection 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6288193/ (Full article)

The UK ME/CFS Biobank for biomedical research on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Multiple Sclerosis

Abstract:

The UK ME/CFS Biobank was launched in August 2011 following extensive consultation with professionals and patient representatives. The bioresource aims to enhance research on myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), related to pathophysiology, biomarkers and therapeutic approaches. The cohort includes 18–60 year olds, encompassing 284 clinically-confirmed ME/CFS cases, 60 neurologist-diagnosed multiple sclerosis (MS) cases, and 135 healthy individuals. The Biobank contains blood samples, aliquoted into serum, plasma, peripheral blood mononuclear cells (PBMC), red blood cells/granulocyte pellet, whole blood, and RNA (totalling 29,863 aliquots). Extensive dataset (700 clinical and socio-demographic variables/participant) enables comprehensive phenotyping. Potential reuse is conditional to ethical approval.

Source: Eliana M Lacerda , Erinna W Bowman, Jacqueline M Cliff, Caroline C Kingdon, Elizabeth C King, Ji-Sook Lee, Taane G Clark, Hazel M Dockrell, Eleanor M Riley, Hayley Curran, Luis Nacul. The UK ME/CFS Biobank for biomedical research on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Multiple Sclerosis. Open Journal of Bioresources. 4(1), p.4. DOI: http://doi.org/10.5334/ojb.28 http://openbioresources.metajnl.com/articles/10.5334/ojb.28/ (Full article)

Considerations in establishing a post-mortem brain and tissue bank for the study of myalgic encephalomyelitis/chronic fatigue syndrome: a proposed protocol

Abstract:

BACKGROUND: Our aim, having previously investigated through a qualitative study involving extensive discussions with experts and patients the issues involved in establishing and maintaining a disease specific brain and tissue bank for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), was to develop a protocol for a UK ME/CFS repository of high quality human tissue from well characterised subjects with ME/CFS and controls suitable for a broad range of research applications. This would involve a specific donor program coupled with rapid tissue collection and processing, supplemented by comprehensive prospectively collected clinical, laboratory and self-assessment data from cases and controls.

FINDINGS: We reviewed the operations of existing tissue banks from published literature and from their internal protocols and standard operating procedures (SOPs). On this basis, we developed the protocol presented here, which was designed to meet high technical and ethical standards and legal requirements and was based on recommendations of the MRC UK Brain Banks Network. The facility would be most efficient and cost-effective if incorporated into an existing tissue bank. Tissue collection would be rapid and follow robust protocols to ensure preservation sufficient for a wide range of research uses. A central tissue bank would have resources both for wide-scale donor recruitment and rapid response to donor death for prompt harvesting and processing of tissue.

CONCLUSION: An ME/CFS brain and tissue bank could be established using this protocol. Success would depend on careful consideration of logistic, technical, legal and ethical issues, continuous consultation with patients and the donor population, and a sustainable model of funding ideally involving research councils, health services, and patient charities. This initiative could revolutionise the understanding of this still poorly-understood disease and enhance development of diagnostic biomarkers and treatments.

 

Source: Nacul L, O’Donovan DG, Lacerda EM, Gveric D, Goldring K, Hall A, Bowman E, Pheby D. Considerations in establishing a post-mortem brain and tissue bank for the study of myalgic encephalomyelitis/chronic fatigue syndrome: a proposed protocol. BMC Res Notes. 2014 Jun 18;7:370. doi: 10.1186/1756-0500-7-370. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4076507/ (Full article)

 

Chronic fatigue syndrome: a review

Abstract:

Chronic fatigue syndrome is a relatively unknown and underdiagnosed entity in Italy where its epidemiology remains uncertain, as well as its etiology, although it causes important disability in those affected. Classification criteria by Fukuda are available to diagnose the syndrome. Its epidemiology indicates that it is probably more frequent in Northern countries and it is described in Gulf War veterans. Etiological hypotheses include infectious diseases, immunology and neurology. Among these hypotheses sickness behavior mimes certain aspects of this syndrome and is characterized by a cytokine imbalance in the central nervous system and in the periphery. There are no valid therapies available at the moment. In the laboratory of Immunogenetics, we are constituting a biological bank of the syndrome to study the immunogenetic aspects of the disease in the hope of elucidating some of the obscure areas of its etiopathogenesis.

 

Source: Carlo-Stella N, Lorusso L, Candura SM, Cuccia M. Chronic fatigue syndrome: a review. Recenti Prog Med. 2004 Nov;95(11):546-52; quiz 560. [Article in Italian] http://www.ncbi.nlm.nih.gov/pubmed/15598093