NK cell activity – American ME and CFS Society

A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Compromised natural killer (NK) cell cytotoxic function is a well-documented and consistent feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Other outcomes evaluated in NK cells of ME/CFS patients, however, remain equivocal. The aim of this study was to conduct a systematic review of the literature regarding NK cell phenotype, receptor expression, cytokine production and cytotoxicity in ME/CFS patients and determine the appropriateness as a model for ME/CFS.

METHODS: Medline (EBSCOHost), Scopus, EMBASE and PubMed databases were systematically searched to source relevant papers published between 1994 and March 2018. This review included studies examining NK cells’ features in ME/CFS patients compared with HC following administration of specific inclusion and exclusion criteria. Secondary outcomes included genetic analysis in isolated NK cells or quality of life assessment. Quality assessment was completed using the Downs and Black checklist in addition to The Joanna Briggs Institute checklist.

RESULTS: Seventeen eligible publications were included in this review. All studies were observational case control studies. Of these, 11 investigated NK cell cytotoxicity, 14 investigated NK cell phenotype and receptor profiles, three examined NK cell cytokine production, six investigated NK cell lytic protein levels and four investigated NK cell degranulation. Impaired NK cell cytotoxicity remained the most consistent immunological report across all publications. Other outcomes investigated differed between studies.

CONCLUSION: A consistent finding among all papers included in this review was impaired NK cell cytotoxicity, suggesting that it is a reliable and appropriate cellular model for continued research in ME/CFS patients. Aberrations in NK cell lytic protein levels were also reported. Although additional research is recommended, current research provides a foundation for subsequent investigations. It is possible that NK cell abnormalities can be used to characterise a subset of ME/CFS due to the heterogeneity of both the illness itself and findings between studies investigating specific features of NK function.

Source: Eaton-Fitch N, du Preez S, Cabanas H, Staines D, Marshall-Gradisnik S. A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome. Syst Rev. 2019 Nov 14;8(1):279. doi: 10.1186/s13643-019-1202-6. https://www.ncbi.nlm.nih.gov/pubmed/31727160

Impaired calcium mobilization in natural killer cells from chronic fatigue syndrome/myalgic encephalomyelitis patients is associated with transient receptor potential melastatin 3 ion channels

Abstract:

Transient receptor potential melastatin subfamily 3 (TRPM3) ion channels play a role in calcium (Ca2+ ) cell signalling. Reduced TRPM3 protein expression has been identified in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) patients. However, the significance of TRPM3 and association with intracellular Ca2+ mobilization has yet to be determined.

Fifteen CFS/ME patients (mean age 48·82 ± 9·83 years) and 25 healthy controls (mean age 39·2 ± 12·12 years) were examined. Isolated natural killer (NK) cells were labelled with fluorescent antibodies to determine TRPM3, CD107a and CD69 receptors on CD56dim CD16+ NK cells and CD56bright CD16dim/- NK cells. Ca2+ flux and NK cytotoxicity activity was measured under various stimulants, including pregnenolone sulphate (PregS), thapsigargin (TG), 2-aminoethoxydiphenyl borate (2APB) and ionomycin.

Unstimulated CD56bright CD16dim/- NK cells showed significantly reduced TRPM3 receptors in CFS/ME compared with healthy controls (HC). Ca2+ flux showed no significant difference between groups. Moreover, PregS-stimulated CD56bright CD16dim/- NK cells showed a significant increase in Ca2+ flux in CFS/ME patients compared with HC. By comparison, unstimulated CD56dim CD16+ NK cells showed no significant difference in both Ca2+ flux and TRPM3 expression. PregS-stimulated CD56dim CD16+ NK cells increased TRPM3 expression significantly in CFS/ME, but this was not associated with a significant increase in Ca2+ flux.

Furthermore, TG-stimulated CD56dim CD16+ NK cells increased K562 cell lysis prior to PregS stimulation in CFS/ME patients compared with HC. Differential expression of TRPM3 and Ca2+ flux between NK cell subtypes may provide evidence for their role in the pathomechanism involving NK cell cytotoxicity activity in CFS/ME.

Source: Nguyen T, Johnston S, Clarke L, Smith P, Staines D, Marshall-Gradisnik S. Impaired calcium mobilization in natural killer cells from chronic fatigue syndrome/myalgic encephalomyelitis patients is associated with transient receptor potential melastatin 3 ion channels. Clin Exp Immunol. 2017 Feb;187(2):284-293. doi: 10.1111/cei.12882. Epub 2016 Nov 23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5217865/ (Full article)

Natural killer cells and single nucleotide polymorphisms of specific ion channels and receptor genes in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

AIM: The aim of this paper was to determine natural killer (NK) cytotoxic activity and if single nucleotide polymorphisms (SNPs) and genotypes in transient receptor potential (TRP) ion channels and acetylcholine receptors (AChRs) were present in isolated NK cells from previously identified myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) patients.

SUBJECTS AND METHODS: A total of 39 ME/CFS patients (51.69±2 years old) and 30 unfatigued controls (47.60±2.39 years old) were included in this study. Patients were defined according to the 1994 Centers for Disease Control and Prevention criteria. Flow cytometry protocols were used to examine NK cytotoxic activity. A total of 678 SNPs from isolated NK cells were examined for 21 mammalian TRP ion channel genes and for nine mammalian AChR genes via the Agena Bioscience iPlex Gold assay. SNP association and genotype was determined using analysis of variance and Plink software.

RESULTS: ME/CFS patients had a significant reduction in NK percentage lysis of target cells (17%±4.68%) compared with the unfatigued control group (31%±6.78%). Of the 678 SNPs examined, eleven SNPs for TRP ion channel genes (TRPC4, TRPC2, TRPM3, and TRPM8) were identified in the ME/CFS group. Five of these SNPs were associated with TRPM3, while the remainder were associated with TRPM8, TRPC2, and TRPC4 (P<0.05). Fourteen SNPs were associated with nicotinic and muscarinic AChR genes: six with CHRNA3, while the remainder were associated with CHRNA2, CHRNB4, CHRNA5, and CHRNE (P<0.05). There were sixteen genotypes identified from SNPs in TRP ion channels and AChRs for TRPM3 (n=5), TRPM8 (n=2), TRPC4 (n=3), TRPC2 (n=1), CHRNE (n=1), CHRNA2 (n=2), CHRNA3 (n=1), and CHRNB4 (n=1) (P<0.05).

CONCLUSION: We identified a number of SNPs and genotypes for TRP ion channels and AChRs from isolated NK cells in patients with ME/CFS, suggesting these SNPs and genotypes may be involved in changes in NK cell function and the development of ME/CFS pathology. These anomalies suggest a role for dysregulation of Ca(2+) in AChR and TRP ion channel signaling in the pathomechanism of ME/CFS.

Source: Marshall-Gradisnik S, Huth T, Chacko A, Johnston S, Smith P, Staines D. Natural killer cells and single nucleotide polymorphisms of specific ion channels and receptor genes in myalgic encephalomyelitis/chronic fatigue syndrome. Appl Clin Genet. 2016 Mar 31;9:39-47. doi: 10.2147/TACG.S99405. ECollection 2016. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4821384/ (Full article)

Pilot Study of Natural Killer Cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Multiple Sclerosis

Abstract:

Patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and multiple sclerosis (MS) suffer from debilitating fatigue which is not alleviated by rest. In addition to the fatigue-related symptoms suffered by patients with CFS/ME and MS, dysfunction of the immune system and, in particular, reduced natural killer (NK) cell cytotoxic activity has also been reported in CFS/ME and MS. The purpose of this pilot study was to compare NK cellular mechanisms in patients with CFS/ME and MS to investigate potential dysfunctions in the NK cell activity pathway. Flow cytometry protocols assessed CD56(dim) CD16(+) and CD56(bright) CD16(+/-) NK cell expression of adhesion molecules, NK activating and inhibiting receptors, NK cell maturation and lytic proteins.

All participants in this study were female and included 14 patients with CFS/ME, nine patients with MS and 19 non-fatigued controls. The patient groups and the non-fatigued controls were not taking any immunosuppressive or immune-enhancing medications. In the MS cohort, KIR2DL5 was significantly increased on CD56(bright) CD16(+/-) NK cells and expression of CD94 was significantly increased on CD56(dim) CD16(+) NK cells in comparison with the controls. Co-expression of CD57 and perforin was significantly increased on CD56(dim) CD16(+) NK cells from patients with CFS/ME compared to the MS and non-fatigued control participants.

The results from this pilot study suggest that NK cells from patients with CFS/ME and MS may have undergone increased differentiation in response to external stimuli which may affect different mechanisms in the NK cell cytotoxic activity pathway.

Source: Huth TK, Brenu EW, Ramos S, Nguyen T, Broadley S, Staines D, Marshall-Gradisnik S. Pilot Study of Natural Killer Cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Multiple Sclerosis. Scand J Immunol. 2016 Jan;83(1):44-51. doi: 10.1111/sji.12388. http://onlinelibrary.wiley.com/wol1/doi/10.1111/sji.12388/full (Full article)

Longitudinal investigation of natural killer cells and cytokines in chronic fatigue syndrome/myalgic encephalomyelitis

Abstract:

BACKGROUND: Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is an etiologically unexplained disorder characterised by irregularities in various aspects of the immunological function. Presently, it is unknown whether these immunological changes remain consistent over time. This study investigates Natural Killer (NK) cell cytotoxic activity, NK cell subsets (CD56brightCD16- and CD56dimCD16+) and cytokines, over the course of a12 month period in patients with CFS/ME.

METHODS: The participants in the study comprised 65 (47.2 ± 11.5 years) CFS/ME participants and 21 (45.2 ± 9.3 years) non-fatigued controls. Flow cytometry protocols were used to assess NK subsets and NK cytotoxic activity at various time points that included baseline (T1), 6 (T2) and 12 months (T3). Cytokine secretions were measured following mitogenic stimulation of peripheral blood mononuclear cells.

RESULTS: NK cytotoxic activity was significantly decreased in the CFS/ME patients at T1, T2 and T3 compared to the non-fatigued group. Additionally, in comparison to the non-fatigued controls, the CFS/ME group had significantly lower numbers of CD56brightCD16- NK cells at both T1 and T2. Interestingly, following mitogenic stimulation, cytokine secretion revealed significant increases in IL-10, IFN-γ and TNF-α at T1 in the CFS/ME group. A significant decrease was observed at T2 in the CFS/ME group for IL-10 and IL-17A while at T3, IL-2 was increased in the CFS/ME group in comparison to the non-fatigued controls. Overall cytotoxic activity was significantly decreased at T3 compared to T1 and T2. CD56brightCD16- NK cells were much lower at T2 compared to T1 and T3. IL-10 and IL-17A secretion was elevated at T2 in comparison to T1 and T3.

CONCLUSION: These results confirm decreases in immune function in CFS/ME patients, suggesting an increased susceptibility to viral and other infections. Furthermore, NK cytotoxic activity may be a suitable biomarker for diagnosing CFS/ME as it was consistently decreased during the course of the 12 months study.

Source: Brenu EW, van Driel ML, Staines DR, Ashton KJ, Hardcastle SL, Keane J, Tajouri L, Peterson D, Ramos SB, Marshall-Gradisnik SM. Longitudinal investigation of natural killer cells and cytokines in chronic fatigue syndrome/myalgic encephalomyelitis. J Transl Med. 2012 May 9;10:88. doi: 10.1186/1479-5876-10-88. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3464733/ (Full article)

Immunologic and psychosocial status in chronic fatigue syndrome

Abstract:

OBJECTIVE: The aim of the study was to investigate the immunologic functions and psychosocial status in patients with chronic fatigue syndrome (CFS).

METHODS: Twenty-five patients with CFS diagnosed by the international CFS definition criteria and 20 age- and gender-matched healthy controls were recruited. Depression was assessed by Beck Depression Inventory (BDI) and health status was assessed by Nottingham Health Profile (NHP). Monoclonal antibodies (MAbs) were measured to identify the following NK cell subsets: CD3, CD4, CD8 and CD56 and cytokine measurements were performed for IL2r, IL6 and IL8 in both patients and control subjects.

RESULTS: The BDI and NHP scores of CFS group were found to be significantly higher than in the control group. The absolute numbers of CD56 cell were also significantly decreased in the patients with CFS compared with the healthy controls. There were no other significant differences of NK cell activity (CD3, CD4 and CD8) and there were significant differences in IL6 and IL2r levels between patients and controls. There were significant correlations between serum IL-6 level and sleep, social isolation and physical ability NHP subscores, and between CD56 NK cell activity and emotional reaction NHP sub score in CFS patients.

CONCLUSION: Significantly higher ratios of psychological and physical disturbances were found in patients with CFS. Decreased CD56 NK cell activity and increased IL2r levels seem to be important immunopathologic changes in CFS. IL-6 and CD 56 NK cell activity may play an important role in sleep, physical, social, and physicological manifestations of CFS (Tab. 3, Fig. 1, Ref. 36).

Full Text in free PDF http://bmj.fmed.uniba.sk/2011/11204-12.pdf

Source: Nas K, Cevik R, Batum S, Sarac AJ, Acar S, Kalkanli S. Immunologic and psychosocial status in chronic fatigue syndrome. Bratisl Lek Listy. 2011;112(4):208-12. https://www.ncbi.nlm.nih.gov/pubmed/21585130

Excess of activating killer cell immunoglobulin‑like receptors and lack of HLA-Bw4 ligands: a two‑edged weapon in chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is an inflammatory disease of unknown aetiology. Researchers have proposed infectious, neurological and immunological causes of this syndrome. Recently, the xenotropic murine leukemia virus-related virus was detected in 67% of patients with CFS in a US study. This observation is in agreement with one ascertained aspect of the disease: a decreased efficiency in NK cell lytic activity in CFS patients. Here, we analyzed the genomic polymorphism of killer cell immunoglobulin-like receptors (KIRs) and their HLA class I cognate ligands in patients with certified CFS. An excess of KIR3DS1 was found in CFS patients with respect to controls, as well as an increased frequency of the genotype missing KIR2DS5. Forty-four CFS patients and 50 controls also underwent genomic typing for the HLA-ligands. In the patients, a great proportion of KIR3DL1 and KIR3DS1 receptors were found to be missing their HLA-Bw4Ile80 binding motif. We hypothesize that an excess of KIR3DS1, combined with an excess of ligand-free KIR3DL1 and KIR3DS1 receptors, may hamper the clearance of a pathogen via NK cells, thus favouring the chronicity of the infection.

Source: Pasi A, Bozzini S, Carlo-Stella N, Martinetti M, Bombardieri S, De Silvestri A, Salvaneschi L, Cuccia M. Excess of activating killer cell immunoglobulin‑like receptors and lack of HLA-Bw4 ligands: a two‑edged weapon in chronic fatigue syndrome. Mol Med Rep. 2011 May-Jun;4(3):535-40. doi: 10.3892/mmr.2011.447. Epub 2011 Mar 4. https://www.ncbi.nlm.nih.gov/pubmed/21468604

Immune and hemorheological changes in chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic Fatigue Syndrome (CFS) is a multifactorial disorder that affects various physiological systems including immune and neurological systems. The immune system has been substantially examined in CFS with equivocal results, however, little is known about the role of neutrophils and natural killer (NK) phenotypes in the pathomechanism of this disorder. Additionally the role of erythrocyte rheological characteristics in CFS has not been fully expounded. The objective of this present study was to determine deficiencies in lymphocyte function and erythrocyte rheology in CFS patients.

METHODS: Flow cytometric measurements were performed for neutrophil function, lymphocyte numbers, NK phenotypes (CD56(dim)CD16(+) and CD56(bright)CD16(-)) and NK cytotoxic activity. Erythrocyte aggregation, deformability and fibrinogen levels were also assessed.

RESULTS: CFS patients (n = 10) had significant decreases in neutrophil respiratory burst, NK cytotoxic activity and CD56(bright)CD16(-) NK phenotypes in comparison to healthy controls (n = 10). However, hemorheological characteristic, aggregation, deformability, fibrinogen, lymphocyte numbers and CD56(dim)CD16(+) NK cells were similar between the two groups.

CONCLUSION: These results indicate immune dysfunction as potential contributors to the mechanism of CFS, as indicated by decreases in neutrophil respiratory burst, NK cell activity and NK phenotypes. Thus, immune cell function and phenotypes may be important diagnostic markers for CFS. The absence of rheological changes may indicate no abnormalities in erythrocytes of CFS patients.

Source: Brenu EW, Staines DR, Baskurt OK, Ashton KJ, Ramos SB, Christy RM, Marshall-Gradisnik SM. Immune and hemorheological changes in chronic fatigue syndrome. J Transl Med. 2010 Jan 11;8:1. doi: 10.1186/1479-5876-8-1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2829521/ (Full article)

Hochu-ekki-to combined with interferon-gamma moderately enhances daily activity of chronic fatigue syndrome mice by increasing NK cell activity, but not neuroprotection

Abstract:

The purpose of this study was to evaluate the beneficial effect of Hochu-ekki-to (TJ-41) combined with interferon-gamma (IFN gamma) on daily activity, immunological and neurological alternation in a mouse model of chronic fatigue syndrome (CFS).

CFS was induced by 6 times of repeated injection of Brucella abortus antigen every 2 weeks. Both single TJ-41 and TJ-41 combined with IFN gamma increased running activity and thymus weight of CFS mice, while thicker thymic cortex together with elevation of natural killer cell activity was only found in the combined treatment group. No significant improvement was observed in the atrophic brain and decreased expression level of brain-derived neurotrophic factor and Bcl-2 mRNA in hippocampus in both treatment groups.

Our results suggest that TJ-41 combined with IFN gamma might have a protective effect on the marked reduction in the activity in a model of CFS via normalization of host immune responses, but not neuroprotection.

Source: Chen R, Moriya J, Luo X, Yamakawa J, Takahashi T, Sasaki K, Yoshizaki F. Hochu-ekki-to combined with interferon-gamma moderately enhances daily activity of chronic fatigue syndrome mice by increasing NK cell activity, but not neuroprotection. Immunopharmacol Immunotoxicol. 2009 Jun;31(2):238-45. doi: 10.1080/08923970802391525.https://www.ncbi.nlm.nih.gov/pubmed/18791913

Impaired natural immunity, cognitive dysfunction, and physical symptoms in patients with chronic fatigue syndrome: preliminary evidence for a subgroup?

Abstract:

OBJECTIVE: The diagnostic criteria of chronic fatigue syndrome (CFS) define a heterogeneous population composed of several subgroups. Past efforts to identify subgroup markers have met with mixed success. This study was designed to examine natural killer cell activity (NKCA) as a potential subgroup marker by comparing the clinical presentations of CFS patients with and without clinically reduced NKCA.

METHODS: Forty-one female CFS patients were classified into having either low or normal NKCA levels. These subgroups were then compared on objective measures of cognitive functioning and subjective assessments of fatigue, vigor, cognitive impairment, and daytime dysfunction.

RESULTS: Relative to CFS patients in the normal-NKCA subgroup, low-NKCA patients reported less vigor, more daytime dysfunction, and more cognitive impairment. In addition, low-NKCA patients performed less on objective measures of cognitive functioning relative to normal-NKCA patients.

CONCLUSIONS: The results are offered as preliminary evidence in support of using NKCA as an immunological subgroup marker in CFS. Findings are also discussed in terms of known associations between dysregulated immune functions, somatic symptoms, and psychological stress.

Source: Siegel SD, Antoni MH, Fletcher MA, Maher K, Segota MC, Klimas N. Impaired natural immunity, cognitive dysfunction, and physical symptoms in patients with chronic fatigue syndrome: preliminary evidence for a subgroup? J Psychosom Res. 2006 Jun;60(6):559-66. https://www.ncbi.nlm.nih.gov/pubmed/16731230