Tag: immune suppression

Immune exhaustion in ME/CFS and long COVID

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID are debilitating multisystemic conditions sharing similarities in immune dysregulation and cellular signaling pathways contributing to the pathophysiology. In this study, immune exhaustion gene expression was investigated in participants with ME/CFS or long COVID concurrently.

RNA was extracted from peripheral blood mononuclear cells isolated from participants with ME/CFS (n = 14), participants with long COVID (n = 15), and healthy controls (n = 18). Participants with ME/CFS were included according to Canadian Consensus Criteria. Participants with long COVID were eligible according to the case definition for “Post COVID-19 Condition” published by the World Health Organization. RNA was analyzed using the NanoString nCounter Immune Exhaustion gene expression panel.

Differential gene expression analysis in ME/CFS revealed downregulated IFN signaling and immunoglobulin genes, and this suggested a state of immune suppression. Pathway analysis implicated dysregulated macrophage activation, cytokine production, and immunodeficiency signaling.

Long COVID samples exhibited dysregulated expression of genes regarding antigen presentation, cytokine signaling, and immune activation. Differentially expressed genes were associated with antigen presentation, B cell development, macrophage activation, and cytokine signaling.

This investigation elucidates the intricate role of both adaptive and innate immune dysregulation underlying ME/CFS and long COVID, emphasizing the potential importance of immune exhaustion in disease progression.

Source: Natalie Eaton-Fitch, Penny Rudd, Teagan Er, Livia Hool, Lara Herrero, and Sonya Marshall-Gradisnik. Immune exhaustion in ME/CFS and long COVID. JCI Insight. 2024;9(20):e183810. https://doi.org/10.1172/jci.insight.183810. https://insight.jci.org/articles/view/183810 (Full text)

Chronic intestinal candidiasis as a possible etiological factor in the chronic fatigue syndrome

Abstract:

The chronic candidiasis syndrome, also known as the Candida-related complex, putatively caused by the overgrowth of Candida albicans in the gastrointestinal tract and secondarily in the genital organs, is briefly described.

Patients with this disorder have many of the same symptoms as those with the chronic fatigue syndrome, except for the recurrent flu-like symptoms of the latter disorder. The positive response of a large number of patients with the chronic fatigue syndrome (CFS) to an oral antifungal agent and a diet for intestinal candidiasis has been described by another clinician.

There is evidence that Candida albicans infection of the mucous membranes depresses T cell and natural killer (NK) cell function. Similar abnormalities of immune function are found in the CFS. The function of cytotoxic T cells, T helper cells, and NK cells is important in preventing reactivation of infections from Epstein-Barr virus, cytomegalovirus, and other herpesviruses.

Reactivation of one or more of these viruses could lead to the expression of the flu-like symptoms in the CFS. Yet the immune dysfunction found in this disorder has been considered the primary underlying causal factor.

It is proposed that chronic intestinal candidiasis may be an agent which leads to immune depression in many CFS patients and therefore that it could be a causal factor in CFS.

 

Source: Cater RE 2nd. Chronic intestinal candidiasis as a possible etiological factor in the chronic fatigue syndrome. Med Hypotheses. 1995 Jun;44(6):507-15. http://www.ncbi.nlm.nih.gov/pubmed/7476598

 

The chronic fatigue syndrome

Abstract:

CFIDS (chronic fatigue and immune disfunction syndrome) is also known as CFS (chronic fatigue syndrome), CEBV (chronic Epstein-Barr virus), M.E. (myalgic encephalomyelitis), yuppie flu and by other names.

It is a complex illness characterized by incapacitating fatigue (experienced as exhaustion and extremely poor stamina), neurological problems and a constellation of symptoms that can resemble many disorders, including; mononucleosis, multiple sclerosis, fibromyalgia, AIDS-related complex (ARC) and autoimmune diseases such as lupus. These symptoms tend to wax and wane, but any often severely debilitating and may last for many months or years. All sections of the population (including children) are at risk, but women under 45 seem to be most susceptible.

The investigators suggest that CFIDS results from dysfunction of the immune system. The exact nature of this dysfunction is not yet well defined, but it can generally be viewed as an unregulated or overactive state which is responsible for most of the symptoms. There is also evidence of some immune suppression in CFIDS. None of the treatments is consistently satisfactory, but some may be helpful: psychotherapy, physiotherapy, exercise programs, acupunctures, small doses of antidepressants, etc.

 

Source: Artsimovich NG, Chugunov VS, Kornev AV, Ivanova TM, Chugunov AV, Oprishchenko MA. The chronic fatigue syndrome. Zh Nevrol Psikhiatr Im S S Korsakova. 1994;94(5):47-50. [Article in Russian] http://www.ncbi.nlm.nih.gov/pubmed/7900453

 

Infection of natural killer cells by human herpesvirus 6

Abstract:

Natural killer (NK) cells are a functionally defined subset of non-T, non-B lymphocytes of bone marrow origin, which induce lysis of selected target cells, including neoplastic and virus-infected cells. The NK cell function provides an important mechanism of primary defence against viruses in vivo, as demonstrated by the occurrence of multiple herpesvirus infections in patients congenitally lacking NK cells.

Here we show that functionally competent CD3- NK clones can be productively infected by human herpesvirus 6 (HHV-6), a T-lymphotropic DNA virus that may play a role in the acquired immunodeficiency syndrome (AIDS) and in the chronic fatigue syndrome, two disorders associated with a defective NK cell activity.

The infection is cytopathic and induces de novo expression of CD4, an antigen not expressed within the NK lineage, thereby predisposing NK cells to infection by human immunodeficiency virus type 1 (HIV-1).

These results provide evidence that a herpesvirus can directly target and kill NK cells, a potential strategy to suppress the natural anti-viral immunity of the host.

 

Source: Lusso P, Malnati MS, Garzino-Demo A, Crowley RW, Long EO, Gallo RC. Infection of natural killer cells by human herpesvirus 6. Nature. 1993 Apr 1;362(6419):458-62. http://www.ncbi.nlm.nih.gov/pubmed/7681936