Measurement of Genetic Variations in ME/CFS Patients in the IDO2 Gene Encoding an Enzyme Metabolizing Tryptophan

Abstract:

Genetic variations in the indoleamine 2,3-dioxygenase (IDO2) gene that are commonly found in the general population have been assessed for their frequency in myalgic encephalomyelitis/chronic fatigue (ME/CFS) patients compared with healthy controls. They have potential for being genetic variations that lead to susceptibility to developing ME/CFS following exposure to a triggering stressor like a viral infection or other major stress events.

The IDO2 gene encodes an enzyme that is involved in the tryptophan-kynurenine pathway (TKP), and is activated if there are excessive amounts of tryptophan to prevent excessive serotonin production. The TKP pathway through production of NADH is involved in regulating the immune system and likely plays an important role in ME/CFS.

A simple method was developed to evaluate the 5 commonly occurring mutations in this gene in ME/CFS patients and to determine if one or more were present at higher frequency than in healthy controls. This might indicate a susceptibility factor for developing ME/CFS. In this chapter we describe the techniques used to isolate peripheral blood mononuclear cells (PBMCs), extract the DNA, and then do touchdown PCR and DNA sequencing for the analysis.

Source: Edgar CD, Blair A, Tate WP. Measurement of Genetic Variations in ME/CFS Patients in the IDO2 Gene Encoding an Enzyme Metabolizing Tryptophan. Methods Mol Biol. 2025;2920:247-256. doi: 10.1007/978-1-0716-4498-0_14. PMID: 40372687. https://link.springer.com/protocol/10.1007/978-1-0716-4498-0_14

HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity

Abstract:

Research of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and fibromyalgia (FM), two acquired chronic illnesses affecting mainly females, has failed to ascertain their frequent co-appearance and etiology. Despite prior detection of human endogenous retrovirus (HERV) activation in these diseases, the potential biomarker value of HERV expression profiles for their diagnosis, and the relationship of HERV expression profiles with patient immune systems and symptoms had remained unexplored.

By using HERV-V3 high-density microarrays (including over 350k HERV elements and more than 1500 immune-related genes) to interrogate the transcriptomes of peripheral blood mononuclear cells from female patients diagnosed with ME/CFS, FM, or both, and matched healthy controls (n = 43), this study fills this gap of knowledge. Hierarchical clustering of HERV expression profiles strikingly allowed perfect participant assignment into four distinct groups: ME/CFS, FM, co-diagnosed, or healthy, pointing at a potent biomarker value of HERV expression profiles to differentiate between these hard-to-diagnose chronic syndromes.

Differentially expressed HERV-immune-gene modules revealed unique profiles for each of the four study groups and highlighting decreased γδ T cells, and increased plasma and resting CD4 memory T cells, correlating with patient symptom severity in ME/CFS. Moreover, activation of HERV sequences coincided with enrichment of binding sequences targeted by transcription factors which recruit SETDB1 and TRIM28, two known epigenetic silencers of HERV, in ME/CFS, offering a mechanistic explanation for the findings.

Unexpectedly, HERV expression profiles appeared minimally affected in co-diagnosed patients denoting a new nosological entity with low epigenetic impact, a seemingly relevant aspect for the diagnosis and treatment of this prevalent group of patients.

Source: Giménez-Orenga K, Martín-Martínez E, Nathanson L, Oltra E. HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity. Elife. 2025 May 8;14:RP104441. doi: 10.7554/eLife.104441. PMID: 40338225. https://elifesciences.org/articles/104441 (Full text)

In vitro effects of echinacea and ginseng on natural killer and antibody-dependent cell cytotoxicity in healthy subjects and chronic fatigue syndrome or acquired immunodeficiency syndrome patients

Abstract:

Extracts of Echinacea purpurea and Panax ginseng were evaluated for their capacity to stimulate cellular immune function by peripheral blood mononuclear cells (PBMC) from normal individuals and patients with either the chronic fatigue syndrome or the acquired immunodeficiency syndrome.

PBMC isolated on a Ficoll-hypaque density gradient were tested in the presence or absence of varying concentrations of each extract for natural killer (NK) cell activity versus K562 cells and antibody-dependent cellular cytotoxicity (ADCC) against human herpesvirus 6 infected H9 cells. Both echinacea and ginseng, at concentrations > or = 0.1 or 10 micrograms/kg, respectively, significantly enhanced NK-function of all groups. Similarly, the addition of either herb significantly increased ADCC of PBMC from all subject groups.

Thus, extracts of Echinacea purpurea and Panax ginseng enhance cellular immune function of PBMC both from normal individuals and patients with depressed cellular immunity.

 

Source: See DM, Broumand N, Sahl L, Tilles JG. In vitro effects of echinacea and ginseng on natural killer and antibody-dependent cell cytotoxicity in healthy subjects and chronic fatigue syndrome or acquired immunodeficiency syndrome patients. Immunopharmacology. 1997 Jan;35(3):229-35. http://www.ncbi.nlm.nih.gov/pubmed/9043936

 

Demonstration of Borna disease virus RNA in peripheral blood mononuclear cells derived from Japanese patients with chronic fatigue syndrome

Abstract:

CFS, a recently named heterogeneous disorder, is an illness of unknown etiology. The association of CFS with viral infections has been suggested. A common association between CFS and several viruses examined has not been confirmed.

Here, we centered on the possible link between CFS and BDV infection. By nested RT-PCR followed by hybridization, BDV RNA was demonstrated as a clear signal in PBMCs in 3 out of 25 CFS patients. The amplified cDNA fragments were cloned and sequenced. A total of 16 clones were studied. Intra-patients divergencies of the p24 were 2-9%, 3-20%, and 3-11% in the deduced amino acids. Inter-patient divergencies among the 16 clones were 3-24%. Antibodies to recombinant BDV p24 protein were detected in 6 CFS patients including one carrying BDV RNA.

Overall, these gave the prevalence of 32% (8/25) in Japanese CFS patients, suggesting that Japanese CFS is highly associated with active infection of BDV, or a related agent.

 

Source: Nakaya T, Takahashi H, Nakamura Y, Asahi S, Tobiume M, Kuratsune H, Kitani T, Yamanishi K, Ikuta K. Demonstration of Borna disease virus RNA in peripheral blood mononuclear cells derived from Japanese patients with chronic fatigue syndrome. FEBS Lett. 1996 Jan 8;378(2):145-9. http://onlinelibrary.wiley.com/doi/10.1016/0014-5793(95)01439-X/epdf (Full article)

 

Altered cytokine release in peripheral blood mononuclear cell cultures from patients with the chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is an idiopathic illness associated with a variety of immunologic abnormalities. To investigate potential pathogenetic mechanisms, we evaluated serum levels and peripheral blood mononuclear cell (PBMC) production of selected cytokines and immunoglobulins.

Serum bioactive transforming growth factor beta (TGF-beta) levels were higher (P less than 0.01) in patients with CFS (290 +/- 46 pg/mL) than in control subjects (104 +/- 18 pg/mL), but levels of other cytokines tested were not different. Lipopolysaccharide-stimulated release of interleukin 1 beta (IL-1 beta), IL-6, and tumor necrosis factor-alpha was increased (P less than 0.05) in PBMC cultures from patients with CFS versus control subjects; enhanced (P less than 0.01) IL-6 release to phytohemagglutinin was also observed.

In contrast, TGF-beta release in response to lipopolysaccharide was depressed (P less than 0.01) in PBMC cultures derived from patients with CFS. No differences in IL-2 and IL-4 or immunoglobulin production were observed.

The enhanced release of inflammatory cytokines by stimulated PBMC from patients with CFS suggests that these cells are primed for an increased response to immune stimuli. These data also suggest an association between abnormal regulation of TGF-beta production in vivo and in vitro with the immunologic consequence of CFS.

 

Source: Chao CC1, Janoff EN, Hu SX, Thomas K, Gallagher M, Tsang M, Peterson PK. Altered cytokine release in peripheral blood mononuclear cell cultures from patients with the chronic fatigue syndrome. Cytokine. 1991 Jul;3(4):292-8. http://www.ncbi.nlm.nih.gov/pubmed/1873478