Tag: NK cells

Evaluation of natural killer cell assay performance on shipped blood specimens

Abstract:

Documenting the importance of NK cell function as a biomarker for diseases and physiologic conditions including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), will require assays amenable to clinical implementation and standardization. Research studies typically perform NK functional assays on the day of sample collection. This pilot study was conducted to compare assay formats and specimen processing to identify those that are most tolerant of conditions required for shipping and amenable to standardization as shown by inter-assay and inter-laboratory correlation of results.

We compared performance within and between assays that measure NK cell function using direct cytotoxicity [chromium-51 release (CRCA) or fluorescence (Flow Cytometry Cytotoxicity Assay, FCCA)] or an indirect surrogate marker (CD107a surface expression)]. Additional variables for within/between assay comparisons included time of testing (same day as specimen collection or next day within 24 h), specimen types [whole blood or isolated peripheral blood mononuclear cells (PBMCs)], and processing method (fresh or cryopreserved). Statistical measures included number of samples tested in assay conditions (n), medians (x͂), interquartile range (IQR), Pearson correlation coefficient (R2), and correlation p-value (p).

Samples came from 3 clinics and included 31 participants. Same day testing was only available for the subset of participants enrolled from the site of the laboratory performing CRCA. Results from same day CRCA testing of whole blood were considered the gold standard [n = 10, x͂=10.0%, IQR = 7.2%], and correlated well with PBMCs isolated next day [n = 26, x͂= 15.6%, IQR = 13.1%] [R2 = 0.59, p = 0.03]. Next day CRCA results were compromised using whole blood or frozen PBMCs. Next day FCCA cytotoxicity in PBMC [n = 30, x͂=34.1%, IQR = 15.5%] correlated with same day CRCA PMBC [R2 = 0.8, p = 0.001] and next day CRCA PMBC [R2 = 0.5, p < 0.0001]. CD107a expression after induction by PMA and ionomycin did not correlate with other cytotoxicity measures. NK function can be measured in PBMCs isolated after overnight shipping/storage at ambient temperature and CRCA and FCCA results on this sample type are well correlated.

Source: Querec TD, Abrams J, Stewart JJ, Barnes Z, Balbin E, Klimas N, Fletcher MA, Brown L, Bertolli J, Unger ER. Evaluation of natural killer cell assay performance on shipped blood specimens. J Immunol Methods. 2021 Apr 2:113049. doi: 10.1016/j.jim.2021.113049. Epub ahead of print. PMID: 33819446. https://pubmed.ncbi.nlm.nih.gov/33819446/

Validation of impaired Transient Receptor Potential Melastatin 3 ion channel activity in natural killer cells from Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis patients

Abstract:

BACKGROUND: Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis (CFS/ME) is a complex multifactorial disorder of unknown cause having multi-system manifestations. Although the aetiology of CFS/ME remains elusive, immunological dysfunction and more particularly reduced cytotoxic activity in natural killer (NK) cells is the most consistent laboratory finding. The Transient Receptor Potential (TRP) superfamily of cation channels play a pivotal role in the pathophysiology of immune diseases and are therefore potential therapeutic targets. We have previously identified single nucleotide polymorphisms in TRP genes in peripheral NK cells from CFS/ME patients. We have also described biochemical pathway changes and calcium signaling perturbations in NK cells from CFS/ME patients. Notably, we have previously reported a decrease of TRP cation channel subfamily melastatin member 3 (TRPM3) function in NK cells isolated from CFS/ME patients compared with healthy controls after modulation with pregnenolone sulfate and ononetin using a patch-clamp technique. In the present study, we aim to confirm the previous results describing an impaired TRPM3 activity in a new cohort of CFS/ME patients using a whole cell patch-clamp technique after modulation with reversible TRPM3 agonists, pregnenolone sulfate and nifedipine, and an effective TRPM3 antagonist, ononetin. Indeed, no formal research has commented on using pregnenolone sulfate or nifedipine to treat CFS/ME patients while there is evidence that clinicians prescribe calcium channel blockers to improve different symptoms.

METHODS: Whole-cell patch-clamp technique was used to measure TRPM3 activity in isolated NK cells from twelve age- and sex-matched healthy controls and CFS/ME patients, after activation with pregnenolone sulfate and nifedipine and inhibition with ononetin.

RESULTS: We confirmed a significant reduction in amplitude of TRPM3 currents after pregnenolone sulfate stimulation in isolated NK cells from another cohort of CFS/ME patients compared with healthy controls. The pregnenolone sulfate-evoked ionic currents through TRPM3 channels were again significantly modulated by ononetin in isolated NK cells from healthy controls compared with CFS/ME patients. In addition, we used nifedipine, another reversible TRPM3 agonist to support the previous findings and found similar results confirming a significant loss of the TRPM3 channel activity in CFS/ME patients.

CONCLUSIONS: Impaired TRPM3 activity was validated in NK cells isolated from CFS/ME patients using different pharmacological tools and whole-cell patch-clamp technique as the gold standard for ion channel research. This investigation further helps to establish TRPM3 channels as a prognostic marker and/ or a potential therapeutic target for CFS/ME.

Source: Cabanas H, Muraki K, Balinas C, Eaton-Fitch N, Staines D, Marshall-Gradisnik S. Validation of impaired Transient Receptor Potential Melastatin 3 ion channel activity in natural killer cells from Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis patients. Mol Med. 2019 Apr 23;25(1):14. doi: 10.1186/s10020-019-0083-4. https://www.ncbi.nlm.nih.gov/pubmed/31014226

Cellular immune function in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition with unknown aetiology, unclear pathophysiology and with no diagnostic test or biomarker available. Many patients report their ME/CFS began after an acute infection, and subsequent increased frequency of infections, such as colds or influenza, is common. These factors imply an altered immunological status exists in ME/CFS, in at least a proportion of patients, yet previous studies of peripheral immunity have been discrepant and inconclusive.

The UK ME/CFS Biobank, which has collected blood samples from nearly 300 clinically-confirmed ME/CFS patients, enables large-scale studies of immunological function in phenotypically well-characterised participants. In this study, herpes virus serological status and T cell, B cell, NK cell and monocyte populations were investigated in 251 ME/CFS patients, including 54 who were severely affected, and compared with those from 107 healthy participants and with 46 patients with Multiple Sclerosis.

There were no differences in seroprevalence for six human herpes viruses between ME/CFS and healthy controls, although seroprevalence for the Epstein-Barr virus was higher in multiple sclerosis patients. Contrary to previous reports, no significant differences were observed in NK cell numbers, subtype proportions or in vitro responsiveness between ME/CFS patients and healthy control participants. In contrast, the T cell compartment was altered in ME/CFS, with reduced proportions of effector memory CD8+ T cells and of intermediately differentiated CD8+ T cells in ME/CFS. Conversely, there was a significantly increased proportion of mucosal associated invariant T cells (MAIT) cells, especially in severely affected ME/CFS patients.

These abnormalities demonstrate that an altered immunological state does exist in ME/CFS, particularly in severely affected people. This may simply reflect ongoing or recent infection, or may indicate future increased susceptibility to infection. Longitudinal studies of ME/CFS patients are needed to help to determine cause and effect and thus any potential benefits of immuno-modulatory treatments for ME/CFS.

Source: Jacqueline M. Cliff, Elizabeth C. King, Ji-Sook Lee, Nuno Sepulveda, Asia-Sofia Wolf, Caroline Kingdon, Erinna Bowman, Hazel M. Dockrell, Luis C. Nacul, Eliana Lacerda and Eleanor Riley. Cellular immune function in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Front. Immunol. | doi: 10.3389/fimmu.2019.00796 https://www.frontiersin.org/articles/10.3389/fimmu.2019.00796/full (Full article)

Loss of Transient Receptor Potential Melastatin 3 ion channel function in natural killer cells from Chronic Fatigue Syndrome/Myalgic Encephalomyelitis patients

Abstract:

BACKGROUND: Chronic Fatigue Syndrome (CFS)/ Myalgic Encephalomyelitis (ME) is a debilitating disorder that is accompanied by reduced cytotoxic activity in natural killer (NK) cells. NK cells are an essential innate immune cell, responsible for recognising and inducing apoptosis of tumour and virus infected cells. Calcium is an essential component in mediating this cellular function. Transient Receptor Potential Melastatin 3 (TRPM3) cation channels have an important regulatory role in mediating calcium influx to help maintain cellular homeostasis. Several single nucleotide polymorphisms have been reported in TRPM3 genes from isolated peripheral blood mononuclear cells, NK and B cells in patients with CFS/ME and have been proposed to correlate with illness presentation. Moreover, a significant reduction in both TRPM3 surface expression and intracellular calcium mobilisation in NK cells has been found in CFS/ME patients compared with healthy controls. Despite the functional importance of TRPM3, little is known about the ion channel function in NK cells and the epiphenomenon of CFS/ME. The objective of the present study was to characterise the TRPM3 ion channel function in NK cells from CFS/ME patients in comparison with healthy controls using whole cell patch-clamp techniques.

METHODS: NK cells were isolated from 12 age- and sex-matched healthy controls and CFS patients. Whole cell electrophysiology recording has been used to assess TRPM3 ion channel activity after modulation with pregnenolone sulfate and ononetin.

RESULTS: We report a significant reduction in amplitude of TRPM3 current after pregnenolone sulfate stimulation in isolated NK cells from CFS/ME patients compared with healthy controls. In addition, we found pregnenolone sulfate-evoked ionic currents through TRPM3 channels were significantly modulated by ononetin in isolated NK cells from healthy controls compared with CFS/ME patients.

CONCLUSIONS: TRPM3 activity is impaired in CFS/ME patients suggesting changes in intracellular Ca2+ concentration, which may impact NK cellular functions. This investigation further helps to understand the intracellular-mediated roles in NK cells and confirm the potential role of TRPM3 ion channels in the aetiology and pathomechanism of CFS/ME.

Source: Cabanas H, Muraki K, Eaton N, Balinas C, Staines D, Marshall-Gradisnik S. Loss of Transient Receptor Potential Melastatin 3 ion channel function in natural killer cells from Chronic Fatigue Syndrome/Myalgic Encephalomyelitis patients. Mol Med. 2018 Aug 14;24(1):44. doi: 10.1186/s10020-018-0046-1.

Longitudinal associations of lymphocyte subsets with clinical outcomes in chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is characterized by prolonged fatigue and other physical and neurocognitive symptoms. Some studies suggest that CFS is accompanied by disruptions in the number and function of various lymphocytes. However, it is not clear which lymphocytes might influence CFS symptoms.

PURPOSE: To determine if patient reported fatigue symptoms and physical functioning scores significantly changed across time with lymphocyte counts as evidence of a relation among chronic fatigue symptoms and the immune response.

METHODS: The current longitudinal, naturalistic study assessed the cellular expression of three lymphocyte subtypes — natural killer (NK) cells (CD3-CD16+ and CD3-CD56+) and naïve T cells (CD4+CD45RA+) — to determine whether changes in lymphocytes at 4 time points across 18 months were associated with clinical outcomes, including CFS symptoms, physical functioning, and vitality, among patients with chronic fatigue.. Latent growth curve models were used to examine the longitudinal relationship between lymphocytes and clinical outcomes.

RESULTS: Ninety-three patients with Fukuda-based CFS and seven with non-CFS fatigue provided study data. Results indicated that higher proportions of naïve T cells and lower proportions of NK cells were associated with worse physical functioning, whereas higher proportions of NK cells (CD3-CD16+) and lower proportions of naïve T cells were associated with fewer CFS symptoms.

CONCLUSION: These findings suggest that lymphocytes are modestly related to clinical outcomes over time.

Source: Mehalick ML, Schmaling KB, Sabath DE, Buchwald DS. Longitudinal associations of lymphocyte subsets with clinical outcomes in chronic fatigue syndrome. Fatigue. 2018;6(2):80-91. doi: 10.1080/21641846.2018.1426371. Epub 2018 Jan 12.  https://www.ncbi.nlm.nih.gov/pubmed/30112249

Reduced glycolytic reserve in isolated natural killer cells from Myalgic encephalomyelitis/chronic fatigue syndrome patients: A preliminary investigation

Abstract:

BACKGROUND: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is medically unexplained post-exertional fatigue associated with significant reduction in natural killer cell (NK) cytotoxicity activity. Cytotoxic activity relies on glycolytic flux and mitochondrial respiration to fulfill energetic cellular demands. While mitochondrial dysfunction has been reported in ME/CFS patients, no previous investigation has examined the bioenergetic profile of isolated NK cells from ME/CFS patients.

OBJECTIVE: This study was to determine the metabolic function in resting NK cells from ME/CFS patients.

METHOD: Six ME/CFS patients (aged 50.33±4.95) were age and sex-matched with non-fatigued healthy controls (aged 50.00±5.04). Mitochondrial stress tests measured parameters of mitochondrial function in the NK cells including basal respiration, ATP production, proton leak, maximal respiration, spare respiratory capacity and bioenergetic health index. Glycolytic stress tests measured parameters of glycolytic function such as glycolytic reserve, glycolysis and glycolytic capacity in isolated NK cells from ME/CFS patients and healthy controls using an extracellular flux analyzer, Seahorse XFp.

RESULT: There was a significant reduction of glycolytic reserve in resting NK cells from ME/CFS patients (0.6±0.07 mpH/ min) compared with healthy control (2.25±1.3 mpH/min). Mitochondrial respiration in resting NK cells did not approach statistical significance between ME/CFS patients and healthy controls.

CONCLUSION: These findings suggest resting NK cells from ME/CFS patients have reduced ability to increase glycolytic flux to respond to high energetic demands for ATP production. Hence, the reduced glycolytic reserves we have identified in isolated resting isolated NK cells should be further investigated to assist in understanding ME/CFS pathogenesis.

Source: Nguyen T, Staines D, Johnston S, Marshall-Gradisnik S. Reduced glycolytic reserve in isolated natural killer cells from Myalgic encephalomyelitis/chronic fatigue syndrome patients: A preliminary investigation. Asian Pac J Allergy Immunol. 2018 Jul 8. doi: 10.12932/AP-011117-0188. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29981562

Drug hoped to treat CFS causes impaired immune function, Griffith study says

Reports that a drug used to treat autoimmune diseases and cancer could also treat Chronic Fatigue Syndrome (CFS) have been refuted by a new Griffith University study.

To be published in BMC Pharmacology and Toxicology, the study by Griffith’s National Centre for Neuroimmunology and Emerging Diseases(NCNED) concluded that the use of Rituximab in CFS patients could incur problems with their immune cells and is not beneficial as a potential treatment.

The Natural Killer (NK) cells have vital functions in fighting viruses, bacteria and tumours.

“We found that these functions were significantly impaired when exposed to Rituximab in CFS patients,” says Scientific Co-Director of NCNED, Professor Sonya Marshall-Gradisnik.

CFS – sometimes known as ME (myalgic encephalomyelitis) – is a complex illness characterised by impaired memory and concentration, metabolic, cardiac, gut and immune dysfunction and debilitating muscle pain and fatigue on exertion (also known as neuroimmune exhaustion).

It is estimated that the prevalence rate of CFS/ME worldwide is between 1 and 2 per cent.

Related to the ion channels

The Gold Coast NCNED team has discovered the illness is related to problems in the ion channels that allow calcium into the body’s cells. Calcium is required by almost every cell in the human body and is vital in helping the immune system destroy a virus or infection.

The team has proven that patients with CFS/ME have lower levels of calcium coming into their cells, that their cells store less calcium and that this is the basis of their illness.

Professor Don Staines, Clinical Co-Director of NCNED, says: “These results are important as NK cells are already known to have impaired function in CFS patients, suggesting certain doses of Rituximab may not be beneficial for the treatment of this condition.”

“Undertaking an initial study has enabled us to secure additional research funding from the national competitive grants process from the Mason Foundation where we can now undertake a larger study using this drug in vitro to validate our novel findings,” says Professor Staines.

First author for these world-first scientific findings was PhD student, Ms Natalie Eaton.  She will be presenting the study at an NCNED-sponsored conference later this year.  The focus of the conference will be promoting greater understanding of pathology and pharmacothereapeutics for CFS, through a Research, Innovation, Discovery, Learning and Education (RIDLE) model.

Source: Press Release: Griffith University, March 27, 2018.

Longitudinal associations of lymphocyte subsets with clinical outcomes in chronic fatigue syndrome

Abstract:

Background: Chronic fatigue syndrome (CFS) is characterized by prolonged fatigue and other physical and neurocognitive symptoms. Some studies suggest that CFS is accompanied by disruptions in the number and function of various lymphocytes. However, it is not clear which lymphocytes might influence CFS symptoms.

Purpose: To determine if patient reported fatigue symptoms and physical functioning scores significantly changed across time with lymphocyte counts as evidence of a relation among chronic fatigue symptoms and the immune response.

Methods: The current longitudinal, naturalistic study assessed the cellular expression of three lymphocyte subtypes – natural killer (NK) cells (CD3 − CD16+ and CD3 − CD56+) and naïve T cells (CD4 + CD45RA+) – to determine whether changes in lymphocytes at 4 time points across 18 months were associated with clinical outcomes, including CFS symptoms, physical functioning, and vitality, among patients with chronic fatigue. Latent growth curve models were used to examine the longitudinal relationship between lymphocytes and clinical outcomes.

Results: Ninety-three patients with Fukuda-based CFS and seven with non-CFS fatigue provided study data. Results indicated that higher proportions of naïve T cells and lower proportions of NK cells were associated with worse physical functioning, whereas higher proportions of NK cells (CD3 − CD16+) and lower proportions of naïve T cells were associated with fewer CFS symptoms.

Conclusion: These findings suggest that lymphocytes are modestly related to clinical outcomes over time.

Source: Melissa L. Mehalick, Karen B. Schmaling, Daniel E. Sabath & Dedra S.Buchwald. Longitudinal associations of lymphocyte subsets with clinical outcomes in chronic fatigue syndrome. Fatigue: Biomedicine, Health & Behavior, Published online: 12 Jan 2018. http://www.tandfonline.com/action/showCitFormats?doi=10.1080%2F21641846.2018.1426371

Unperturbed Cytotoxic Lymphocyte Phenotype and Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a debilitating disorder linked to diverse intracellular infections as well as physiological stress. Cytotoxic lymphocytes combat intracellular infections. Their function is attenuated by stress. Despite numerous studies, the role of cytotoxic lymphocytes in ME/CFS remains unclear. Prompted by advances in the understanding of defects in lymphocyte cytotoxicity, the discovery of adaptive natural killer (NK) cell subsets associated with certain viral infections, and compelling links between stress, adrenaline, and cytotoxic lymphocyte function, we reassessed the role of cytotoxic lymphocytes in ME/CFS.

Forty-eight patients from two independent cohorts fulfilling the Canada 2003 criteria for ME/CFS were evaluated with respect to cytotoxic lymphocyte phenotype and function. Results were compared to values from matched healthy controls. Reproducible differences between patients and controls were not found in cytotoxic lymphocyte numbers, cytotoxic granule content, activation status, exocytotic capacity, target cell killing, or cytokine production. One patient expressed low levels of perforin, explained by homozygosity for the PRF1 p.A91V variant. However, overall, this variant was present in a heterozygous state at the expected population frequency among ME/CFS patients.

No single patient displayed any pathological patterns of cellular responses. Increased expansions of adaptive NK cells or deviant cytotoxic lymphocyte adrenaline-mediated inhibition were not observed. In addition, supervised dimensionality reduction analyses of the full, multidimensional datasets did not reveal any reproducible patient/control discriminators.

In summary, employing sensitive assays and analyses for quantification of cytotoxic lymphocyte differentiation and function, cytotoxicity lymphocyte aberrances were not found among ME/CFS patients. These assessments of cytotoxic lymphocytes therefore do not provide useful biomarkers for the diagnosis of ME/CFS.

Source: Theorell J, Bileviciute-Ljungar I, Tesi B, Schlums H, Johnsgaard MS, Asadi-Azarbaijani B, Bolle Strand E, Bryceson YT. Unperturbed Cytotoxic Lymphocyte Phenotype and Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Front Immunol. 2017 Jun 26;8:723. doi: 10.3389/fimmu.2017.00723. eCollection 2017. http://journal.frontiersin.org/article/10.3389/fimmu.2017.00723/full (Full article)

Chronic fatigue syndrome and the immune system: Where are we now?

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterised by multiple symptoms including fatigue, headaches and cognitive impairment, which have a significantly adverse effect on the normal functioning and well-being of the individual. These symptoms are often triggered or worsened following physical or mental exertion. ME/CFS has long been thought of as having a significant immunological component, but reports describing changes in immune function are often inconsistent between study groups.

Although the wide range of physical, neurocognitive and autonomic symptoms reported have seriously hampered attempts to understand pathophysiological pathways, investment in biomedical research in ME/CFS is finally increasing with a number of novel and promising investigations being published. The onset of ME/CFS may often be linked to (viral) infections which would be consistent with a variety of alterations in natural killer (NK) cell function as described by a number of different groups. Consistency in cytokine data has been lacking so far, although recently more sophisticated approaches have led to more robust data from large patient cohorts.

New hope has also been given to sufferers with the possibility that therapies that deplete B cells can result in clinical improvement. To understand the pathogenic mechanism in this complex condition, it is important to consider repeated analysis in different cohorts. In this review, we will discuss the potential of different components of the immune system to be involved in the pathogenesis of ME/CFS.

Copyright © 2017 Elsevier Masson SAS. All rights reserved

 

Source: Mensah FKF, Bansal AS, Ford B, Cambridge G. Chronic fatigue syndrome and the immune system: Where are we now? Neurophysiol Clin. 2017 Apr 11. pii: S0987-7053(17)30006-0. doi: 10.1016/j.neucli.2017.02.002. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28410877