Tag: leaky gut

Chronic fatigue syndrome: number of patients is expected to double due to long-term effects of the COVID-19 pandemic

Press Release:

Up to 80,000 people in Austria are estimated to suffer from chronic fatigue syndrome, also known as ME/CFS or myalgic encephalomyelitis/chronic fatigue syndrome. The number of ME/CFS patients is expected to rise drastically due to long-term effects of the COVID-19 pandemic. However, research in the field has neither identified mechanisms of disease onset nor causal treatment approaches. Scientists at MedUni Vienna have now identified possible biomarkers that could improve the diagnosis and treatment of long-lasting and debilitating fatigue. The study has recently been published in the Journal of Clinical Medicine.

The study by Eva Untersmayr-Elsenhuber and her team from MedUni Vienna’s Center for Pathophysiology, Infectiology and Immunology builds on earlier research on immune disorders and the intestinal barrier function in patients with ME/CFS. It is well known that ME/CFS patients often differ greatly in the clinical manifestations of their disease. However, despite intensive research, there is still no measurable parameter (biomarker) that clearly indicates the disease.

As the MedUni Vienna research team shows, ME/CFS patients can be divided into subgroups based on the function of their immune system. The study was able to identify various biomarkers in the patients that indicate immune system disorders or reduced intestinal barrier function. As a result, differences relevant to clinical care were identified in ME/CFS patients that would have remained undetected without the previous immunological stratification of the ME/CFS patient group. “In our study, we see that the immunological evaluation of ME/CFS patients is of crucial importance. Patients suffering from immunodeficiencies are characterised by an altered innate immune function. In ME/CFS patients with an intact immune system, the intestinal barrier function was reduced,” explains the study’s principal investigator Eva Untersmayr-Elsenhuber. According to the researchers, this not only provides a more detailed insight in different disease mechanisms, but also indicates that depending on the patient’s immune competence, some treatment approaches might be more suitable than others.

The next step will be to review the study results on a larger scale. In order to advance research in the field, the first ME/CFS Biobank in Austria is currently being set up at MedUni Vienna with the support of the WE&ME Foundation. “ME/CFS Biobank Austria” collects human samples, which will be made available for future research projects. Untersmayr-Elsenhuber: “To ensure that ME/CFS research can take place quickly and transnationally in the future, we have been coordinating with research groups in the UK, the Netherlands and Germany from the outset.”

25 per cent of those affected are bedridden

ME/CFS is a severe multisystemic disease that often leads to a high degree of disability. 60 per cent of patients are unable to work full-time and 25 per cent are bedridden. The exact causes of the disease are still unclear. As diagnosis is difficult due to the lack of biomarkers, the number of people affected cannot be precisely quantified. According to current studies, between 26,000 and 80,000 people in Austria suffer from chronic fatigue. Due to Covid-19, this number could double in the next few years. The links between infection with SARS-CoV-2 and ME/CFS are also the subject of intensive research.

JOURNAL

Journal of Clinical Medicine

DOI

10.3390/jcm13010275 

ARTICLE TITLE

Immunological Patient Stratification in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

ARTICLE PUBLICATION DATE

3-Jan-2024

Long Covid, the Gut, and Autoimmune Skin Diseases: A Novel Therapeutic Approach

Abstract:

The dermatological manifestations of Long Covid (LC) have languished in the shadows of chronic fatigue and brain fog. Yet they are all linked by gut dysbiosis and the cytokine triad of TNF-α, IL-1β, and IL-6. The gut microbiome common not only to LC, psoriasis, AA, and vitiligo but also to neurodegenerative disease has been recently described. This gut microbiome induces an altered tryptophan metabolism linked to autoimmune disease. SARS CoV2 invades enterochromaffin cells rich in ACE2 receptors and curtails absorption of the essential amino acid tryptophan and subsequent synthesis of serotonin and melatonin.

This review suggests that an etiologic prebiotic (d-mannose)/probiotic (lactobacilli, bifidobacteria)/postbiotic (butyrate) approach to autoimmune skin disease that improves intestinal barrier integrity and that suppresses the triad of TNF-α, IL-6, and IL-1β may enhance or even eliminate the traditional immunotherapy of targeted monoclonal antibodies, Janus kinase inhibitors, and steroids. Health benefits of this approach extend well beyond suppression of autoimmune skin disease.

Source: Chambers, P.W.; Chambers, S.E. Long Covid, the Gut, and Autoimmune Skin Diseases: A Novel Therapeutic Approach. Preprints 2023, 2023121881. https://doi.org/10.20944/preprints202312.1881.v2 https://www.preprints.org/manuscript/202312.1881/v2 (Full text available as PDF file)

Immunosuppression in ME may underlie energy deficits that drive ME symptomology

Interview of Dr. Armin Alaedini by Bronc

In October of 2023 the UK the Department of Health and Social Care held a public consultation to improve the care/life outcomes for people with ME. It included an acknowledgement that there has been a lack of biomedical research into ME but failed to accept the very negative impact this has had on the lives of people living with the illness. It also failed to point the finger at those responsible for this which includes the National Institute of Clinical Excellence and the Medical Research Council amongst others.

Despite calling for more research into ME there is acknowledgement that this will need substantial sums of money for this to happen. The DHSC consultation also asked for views about its plans which included a section about disability benefits and how the Department of Work and Pensions wants to improve the service it provides to those people who claim disability benefits. This laughable comment ignores the war on people claiming disability benefits which has been waged by the DWP since 2010. To compound matters the British government recently announced that it wants to make it harder for people to claim disability benefits and snoop on their bank accounts.

The DWP has consistently failed to acknowledge the debilitating nature of ME and instead focuses on the fluctuating nature of the illness to deny many people with ME disability benefits such as ESA and PIP.

Thankfully, there is plenty of evidence revealing how people with ME suffer from a suppressed immune response which accounts for many of the debilitating symptoms of the illness.

I recently talked with Dr. Armin Alaedini about his recent research into this issue. Dr Alaedini is an assistant professor at Columbia University and principal investigator at the Alaedini Lab. Its research is aimed at identifying ‘novel biomarkers, understanding disease mechanism, and finding therapeutic targets in gastrointestinal and neuropsychiatric disease.’ He is chair of ME/CFS Biospecimen Resource Access Committee at the National Institute of Neurological Disorders and Stroke and a member of the Neurobiology of Pain Study Section at NIH.

Dr Alaedini took time out of his busy schedule to talk to me about his research into ME.

How did you get involved in the field of ME research?

I have always been interested in the study of complex medical conditions, especially those that are poorly understood and understudied. I became specifically involved in ME research because of my acquaintance with Dr. Suzanne Vernon, who at that time was the chief scientific officer at The Solve ME/CFS Initiative. I was fortunate to have her support for a NIH-funded project, which resulted in our recent publication that demonstrates how microbial translocation links gastrointestinal, immunologic, and metabolic defects in ME/CFS.

In the paper you co-authored, Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome, it notes that the relationship between immunologic, metabolic and gastrointestinal abnormalities remains unclear. In your study you examined two groups of people with ME: one at rest and one undergoing an exercise challenge. They were compared to a group of healthy people. Can you explain what differences you noted between the healthy control group and the people with ME and between the two groups of people with ME? What may have caused this elevated antibody response to microbial agents in people with ME?

I had been particularly intrigued by the fact that gastrointestinal complaints are common in ME/CFS. Data from the patients in our study clearly confirmed this, showing that gastrointestinal symptoms were indeed much more common and more severe in ME/CFS study participants than in the non-ME/CFS controls. Along with this, we found a specific marker of injury or damage to the intestinal lining, called FABP2, to be higher in the blood of ME/CFS participants than in controls, providing a potential biological link to least some of the associated gastrointestinal symptoms. Increased intestinal permeability due to damage can lead to greater translocation of dietary and microbial antigens, which are typically constrained within the gut lumen, across the intestinal barrier. This, in turn, may result in an immune response to those translocated dietary and microbial products to counter and remove the potentially inflammatory antigens from systemic circulation.

Indeed, our data pointed to a significant increase in antibody responses to microbial and dietary antigens in ME/CFS patients in comparison to controls. What especially surprised us, however, was the fact that we did not observe an expected rise in the more immediate, or what we call “acute-phase”, innate immune responses. Specifically, we found that despite the increased markers of intestinal damage and higher antibody responses, ME/CFS patients did not exhibit a significant acute-phase immune response to counter circulating microbial products. This was suggestive of a suppressed systemic immune response that could possibly explain some of the ME/CFS symptoms.

Your study also noted ‘Enhanced antibody response to dietary antigens in ME/CFS’. What might be causing this?

The antibody response to dietary antigens is likely part of the same process resulting from a dysfunctional intestinal barrier that results in an enhanced immune response to the contents of the gut lumen. These would include both microbial and dietary antigens that the immune system is generally tolerant to and does not mount a significant antibody response against under normal conditions.

People with ME suffer from post exertion malaise which means that exercise will exacerbate their symptoms. What differences did you note between the healthy participants and people with ME who took the exercise challenge? What might be causing the differences in their response to exercise?

Intense exercise is known to cause increased intestinal permeability. Therefore, a maximal exercise challenge can be a particularly useful tool to better understand the effect of gut barrier function on the dysfunctional immune responses we were seeing in the ME/CFS cohort. The data from the exercise challenge confirmed our earlier data, suggesting that ME/CFS patients have a dysfunctional immune response, characterized by a suppressed innate/acute-phase response that is ineffective at countering microbial translocation from the intestinal tract into systemic circulation.

At the same time, another part of the immune response, the adaptive immune system, tries to compensate for this dysfunction by producing antibodies against those microbial antigens. However, the antibody response appears to be inadequate, as the ME/CFS patients continued to have increased circulating microbial antigens. We hypothesize that these microbial antigens can trigger downstream inflammatory responses that impact the central nervous system and may contribute to some of the hallmark symptoms of ME/CFS, such as fatigue.

We also compared metabolic responses in response to exercise between ME/CFS and control study participants. Of particular significance, we found a suppression of glucose and citrate metabolic responses in ME/CFS that to some extent correlated with the suppressed innate immune responses in these patients. This dysfunctional metabolic response is not only conceivably capable of contributing to the observed immunosuppression in ME/CFS, but it may also further underlie energy deficits that drive ME/CFS symptomology.

In your study you observed an increase in antibody responses to both microbial and dietary antigens, reflecting greater epithelial cell damage, which point to enhanced translocation of gut luminal antigens across a compromised intestinal barrier in ME/CFS. Did your findings point to a possible treatment for this damage to the intestinal barrier?

Indeed, the data point to a number of potential targets to consider for therapy in the context of ME/CFS. These include reducing or repairing the intestinal damage in order to decrease the microbial translocation; blocking or sequestering the already translocated microbial antigens; reversing the identified defects in the acute-phase immune responses towards the microbial antigens, and targeting the suppressed metabolic pathways.

What further research is needed to address the issues highlighted in your study?

More research is needed to better understand the relevance and level of contribution of the identified defects in the intestinal barrier, immune response, and metabolic pathways to ME/CFS symptomology, as well as to further characterize the molecular pathways involved, in order to move this research closer to development of effective treatments for ME/CFS.

Links between Serotonin Levels and Stress: Cortisol, Candida A./Mycetes, Omega 3/6 Ratio and Dysbiosis (Skatole/Indoxyl Sulfate) Role in Chronic Fatigue Syndrome (CFS) and Depression

Abstract:

Intestinal microbiota attracts daily attention of a growing number of study which have attempted to link gut dysbiosIs with a variety of disease states: irritable bowel syndrome (IBS), inflamed bowel disease (IBD), Crohn’s disease (CD), leaky gut syndrome (LGS), food intolerance, diabetes, metabolic syndrome, cancer, etc.

In our study we analyzed how intestinal dysbiosis may be related to chronic fatigue syndrome (CFS) and depression through the exchange of information through the gut-brain axis (GBA).

We studied 33 subjects, 13 males and 20 females, who reported CFS or/and depression: we investigated their salivary cortisol levels, blood serotonin, omega 3/6 ratio, intestinal dysbiosis (calculated on the urinary levels of indoxyl sulfate and skatole), and we looked for the presence of Candida a. or mycetes in the stool; the data accumulated with this research show a correlation between the presence of Candida a./miceti, indoxyl sulfate urine values beyond the physiological and low serotonin levels.

In addition, data analysis showed that the EPA/DHA values also show pro-inflammatory levels in case of dysbiosis and low serotonina levels. The relationship, however, with cortisol levels requires further research although this study showed a statistically significant positive correlation between these values, measured at specific times, and serotonin levels.

Aims: We investigated the relationship between stress (evaluated through the measurement of salivary cortisol levels) and gastrointestinal efficiency measured as a function of intestinal fermentative and putrefactive dysbiosis, evaluating the levels of urinary indoxyl sulfate in the first case (a possible correlation with the presence of Candida spp or Mycetes in the subjects feces was investigated), urinary skatole levels in the second one, in patients with chronic fatigue syndrome (SFC) and depression.

In these patients we also have studied omega 3/6 ratio, and finally we have analized the impact that the alteration of these parameters can have on the serotonin levels.

This research attemps to highlight the contact points, in some cases not so obvious, among these topics, contact points that, although they give us interesting indications, show the need to be further deepened by analyzing a larger amount of data.

Source: Orlandoni, D.; Di Fede, G.; Mantovani, M.; Nava, C.R.; Tomasi, M.; Fusi, P. Links between Serotonin Levels and Stress: Cortisol, Candida A./Mycetes, Omega 3/6 Ratio and Dysbiosis (Skatole/Indoxyl Sulfate) Role in Chronic Fatigue Syndrome (CFS) and Depression. Preprints 2023, 2023090253. https://doi.org/10.20944/preprints202309.0253.v1 https://www.preprints.org/manuscript/202309.0253/v1 (Full text available as PDF file)

Increased gut permeability and bacterial translocation are associated with fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome: implications for disease-related biomarker discovery

Abstract:

Background: There is growing evidence of the significance of gastrointestinal complaints in the impairment of the intestinal mucosal barrier function and inflammation in fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome. However, data on intestinal permeability and gut barrier dysfunction in FM and ME/CFS are still limited with conflicting results. This study aimed to assess circulating biomarkers potentially related to intestinal barrier dysfunction and bacterial translocation and their association with self-reported symptoms in these conditions.

Methods: A pilot multicentre, cross-sectional cohort study with consecutive enrolment of 22 patients with FM, 30 with ME/CFS, and 26 matched healthy controls. Plasma levels of anti-beta-lactoglobulin antibodies (IgG anti-beta-LGB), zonulin-1 (ZO-1), LPS, sCD14, and IL-1β) were assayed using ELISA. Demographic and clinical characteristics of the participants were recorded using validated self-reported outcome measures. The diagnostic accuracy of each biomarker was assessed using the ROC curve analysis.

Results: FM patients had significantly higher levels of anti-β-LGB, ZO-1, LPS, and sCD14 than healthy controls (all P < 0.0001). In ME/CFS patients, levels of anti-β-LGB, ZO-1, LPS, and sCD14 were significantly higher than controls, but lower than in FM (all P < 0.01), while there was no significant difference in IL-1β level. In the FM and ME/CFS cohorts, both anti-β-LGB and ZO-1 correlated significantly with LPS and sCD14 (P < 0.001 for both). In the FM group, both anti-beta-LGB and ZO-1 were correlated significantly with physical and mental health components on the SF-36 scale (P < 0.05); whereas IL-1beta negatively correlated with the COMPASS-31 score (P < 0.05). In the ME/CFS cohort, ZO-1 was positively correlated with the COMPASS-31 score (P < 0.05). The ROC curve analysis indicated a strong ability of anti-β-LGB, ZO-1, LPS, and sCD14 to predictively distinguish between FM and ME/CFS from healthy controls (P < 0.0001).

Conclusions: Biomarkers of intestinal barrier function and inflammation were associated with autonomic dysfunction assessed by COMPASS-31 scores in FM and ME/CFS respectively. Anti-β-LGB antibodies, ZO-1, LPS, and sCD14 may be putative predictors of intestinal barrier dysfunction in these cohorts. Further studies are needed to assess whether these findings are causal and can therefore be applied in clinical practice.

Source: Franz Martin, Manuel Blanco Suárez2 Paola Zambrano, Óscar Cáceres Calle, Miriam Almirall, Jose Alegre-Martín, Beatriz Lobo, Ana María Gonzalez-Castro, Javier Santos, Joan Carles Domingo, Joanna Jurek, Jesús Castro-Marrero. Increased gut permeability and bacterial translocation are associated with fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome: implications for disease-related biomarker discovery. Front. Immunol., Sec. Mucosal Immunity, Volume 14 – 2023 | doi: 10.3389/fimmu.2023.1253121 https://www.frontiersin.org/articles/10.3389/fimmu.2023.1253121/abstract

Increase in gut permeability and oxidized ldl is associated with post-acute sequelae of SARS-CoV-2

Abstract:

Background: Post-acute sequelae of SARS-CoV-2 (PASC) is marked by persistent or newly developing symptoms beyond 4 weeks of infection. Investigating gut integrity, oxidized lipids and inflammatory markers is important for understanding PASC pathogenesis.

Methods: A cross-sectional study including COVID+ with PASC, COVID+ without PASC, and COVID-negative (COVID-) participants. We measured plasma markers by enzyme-linked immunosorbent assay to assess intestinal permeability (ZONULIN), microbial translocation (lipopolysaccharide-binding protein or LBP), systemic inflammation (high-sensitivity C-reactive protein or hs-CRP), and oxidized low-density lipoprotein (Ox-LDL).

Results: 415 participants were enrolled in this study; 37.83% (n=157) had prior COVID diagnosis and among COVID+, 54% (n=85) had PASC. The median zonulin among COVID- was 3.37 (IQR: 2.13, 4.91) mg/mL, 3.43 (IQR: 1.65, 5.25) mg/mL among COVID+ no PASC, and highest [4.76 (IQR: 3.2, 7.35) mg/mL] among COVID+ PASC+ (p<.0001). The median ox-LDL among COVID- was 47.02 (IQR: 35.52, 62.77) U/L, 57.24 (IQR: 40.7, 75.37) U/L among COVID+ No PASC, and the highest [76.75 (IQR: 59.95, 103.28) U/L] among COVID+ PASC+ (p<.0001). COVID+ PASC+ was positively associated with zonulin (p=0.0002) and ox-LDL (p<.0001), and COVID- was negatively associated with ox-LDL (p=0.01), compared to COVID+ No PASC. Every unit increase in zonulin was associated with 44% higher predicted odds of having PASC [aOR: 1.44 (95%CI: 1.1, 1.9)] and every one-unit increase in ox-LDL was associated with more than four-fold increased odds of having PASC [aOR: 2.44 (95%CI: 1.67, 3.55)].

Conclusions: PASC is associated with increased gut permeability and oxidized lipids. Further studies are needed to clarify whether these relationships are causal which could lead to targeted therapeutics.

Source: Mouchati C, Durieux JC, Zisis SN, Labbato D, Rodgers MA, Ailstock K, Reinert BL, Funderburg NT, McComsey GA. Increase in gut permeability and oxidized ldl is associated with post-acute sequelae of SARS-CoV-2. Front Immunol. 2023 May 12;14:1182544. doi: 10.3389/fimmu.2023.1182544. PMID: 37251403; PMCID: PMC10217362. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10217362/ (Full text)

 

Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19

Abstract:

Long COVID, also known for post-acute sequelae of COVID-19, describes the people who have the signs and symptoms that continue or develop after the acute COVID-19 phase. Long COVID patients suffer from an inflammation or host responses towards the virus approximately 4 weeks after initial infection with the SARS CoV-2 virus and continue for an uncharacterized duration.

Anyone infected with COVID-19 before could experience long-COVID conditions, including the patients who were infected with SARS CoV-2 virus confirmed by tests and those who never knew they had an infection early. People with long COVID may experience health problems from different types and combinations of symptoms over time, such as fatigue, dyspnea, cognitive impairments, and gastrointestinal (GI) symptoms (e.g., nausea, vomiting, diarrhea, decreased or loss of appetite, abdominal pain, and dysgeusia). The critical role of the microbiome in these GI symptoms and long COVID were reported in clinical patients and experimental models.

Here, we provide an overall view of the critical role of the GI tract and microbiome in the development of long COVID, including the clinical GI symptoms in patients, dysbiosis, viral-microbiome interactions, barrier function, and inflammatory bowel disease patients with long COVID. We highlight the potential mechanisms and possible treatment based on GI health and microbiome. Finally, we discuss challenges and future direction in the long COVID clinic and research.

Source: Zhang J, Zhang Y, Xia Y, Sun J. Microbiome and intestinal pathophysiology in post-acute sequelae of COVID-19. Genes Dis. 2023 Jun 19. doi: 10.1016/j.gendis.2023.03.034. Epub ahead of print. PMID: 37362775; PMCID: PMC10278891. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10278891/ (Full text)

Investigating antibody reactivity to the intestinal microbiome in severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystemic disease of unknown aetiology that is characterised by disabling chronic fatigue and involves both the immune and gastrointestinal (GI) systems. Patients display alterations in GI microbiome with a significant proportion experiencing GI discomfort and pain and elevated blood biomarkers for altered intestinal permeability compared with healthy individuals.

To investigate a possible GI origin of ME/CFS we designed a feasibility study to test the hypothesis that ME/CFS pathogenesis is a consequence of increased intestinal permeability that results in microbial translocation and a breakdown in immune tolerance leading to generation of antibodies reactive to indigenous intestinal microbes. Secretory IgA and serum IgG levels and reactivity to intestinal microbes were assessed in five pairs of severe ME/CFS patients and matched same-household healthy controls. For profiling serum IgG we developed IgG-Seq which combines flow-cytometry based bacterial cell sorting and metagenomics to detect mucosal IgG reactivity to the microbiome.

We uncovered evidence for immune dysfunction in severe ME/CFS patients that was characterised by reduced capacity and reactivity of serum IgG to stool microbes, irrespective of their source. This study provides the rationale for additional studies in larger cohorts of ME/CFS patients to further explore immune-microbiome interactions.

Source: Katharine A. Seton, Marianne Defernez, Andrea Telatin, Sumeet K. Tiwari, George M. Savva, Antonietta Hayhoe, Alistair Noble, Ana Carvalho, Steve James, Amolak Bansal, Thomas Wileman, Simon R. Carding. Investigating antibody reactivity to the intestinal microbiome in severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). medRxiv 2023.05.21.23290299; doi: https://doi.org/10.1101/2023.05.21.23290299 https://www.medrxiv.org/content/10.1101/2023.05.21.23290299v1.full-text (Full text)

Studying severe long COVID to understand post-infectious disorders beyond COVID-19

To the Editor — As the COVID Human Genetic Effort consortium (https://www.covidhge.com/), we have studied genetic and immunological determinants of life-threatening COVID-19 pneumonia1, multisystem inflammatory syndrome (MIS-C)2, resistance to SARS-CoV-2 infection3 and ‘COVID toes’4, and here we present our efforts to investigate post-acute COVID-19 syndrome, or ‘long COVID’.

Most people infected with SARS-CoV-2 experience a mild to moderate acute infection, while ~10% develop hypoxemic pneumonia and 3% develop critical illness, which are outcomes associated with older age and male sex. Inborn errors of type I interferon immunity involving the viral sensors TLR7 or TLR3 can explain critical disease in 1–5% of people less than 60 years of age, whereas neutralizing autoantibodies to the type I interferons IFN-α, IFN-β and IFN-ω are seen in 15–20% of people over 70 years of age1, which highlights the importance of type I interferon immunity for protective immunity against acute SARS-CoV-2 infection in the respiratory tract.

Although hypoxemic pneumonia typically occurs 2 weeks after infection, a small fraction of children and young adults develop MIS-C at about 4 weeks after infection. This disorder overlaps Kawasaki disease and superantigen-mediated toxic shock syndrome. Immunological analyses have revealed hyperinflammatory immune responses, distinct from those of acute COVID-19 and Kawasaki disease5, and activation of T cells, possibly by a SARS-CoV-2 superantigen6. There is massive expansion of T cells expressing the T cell receptor (TCR) β-chain variable region TRBV11-2 in combination with variable TCR α-chains and broadly reactive autoantibodies2. Intriguingly, the delayed presentation of MIS-C after infection is at odds with other superantigen-mediated disorders, which might be explained by viral persistence specifically in the intestine and repeated superantigen-mediated activation through a leaky gut. Viral persistence has been proposed to be associated with the degree of activation of the immune system during acute infection with SARS-CoV-27.

Signs and symptoms after SARS-CoV-2 infection have been reported to also persist even longer in some children and adults. The World Health Organization defines the ‘post COVID’ condition as one that “occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms and that last for at least 2 months and cannot be explained by an alternative diagnosis” (https://www.who.int/publications/i/item/WHO-2019-nCoV-Post_COVID-19_condition-Clinical_case_definition-2021.1). Long COVID spans from very mild to severely debilitating disease with objective organ damage, but sometimes the distinction between recovery from post–intensive care unit syndrome and ongoing pathology is not clearly defined or reported in studies.

Interestingly, an acute multi-organ phenotype encompassing multiple neurological, neuropsychological–neurocognitive, cardiopulmonary, gastrointestinal and dermatological complaints during acute COVID-19 correlates with longer persistence of signs and symptoms8.

The World Health Organization’s definition of long COVID is vague, which leads to concerns that a variety of conditions, including psychosomatic complaints, become intermixed with more severe, post-infectious organ dysfunction. To maximize our chances of identifying the human genetic immunological determinants of disease, we will focus our efforts on the most severe cases of long COVID available through our international network of collaborators and clinics. We will include patients with over 3 months of persistent signs and symptoms after PCR-verified SARS-CoV-2 infection. We will also limit our studies to patients with severe organ damage or dysfunction that can be objectively verified by imaging and physiological or biochemical–molecular tests (Fig. 1a). Finally, to distinguish these patients with severe long COVID from patients with post–critical illness syndromes, we will include only patients whose persistent organ dysfunction cannot be explained by the severity of the preceding SARS-CoV-2 infection or by the treatments or medical interventions experienced.

Read the rest of this article HERE.

Source: Brodin P, Casari G, Townsend L, O’Farrelly C, Tancevski I, Löffler-Ragg J, Mogensen TH, Casanova JL; COVID Human Genetic Effort. Studying severe long COVID to understand post-infectious disorders beyond COVID-19. Nat Med. 2022 Apr 5. doi: 10.1038/s41591-022-01766-7. Epub ahead of print. PMID: 35383311. https://www.nature.com/articles/s41591-022-01766-7 (Full article)

The Gut Microbiome in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS)

Abstract:

Myalgic encephalomyelitis (ME) or Chronic Fatigue Syndrome (CFS) is a neglected, debilitating multi-systemic disease without diagnostic marker or therapy. Despite evidence for neurological, immunological, infectious, muscular and endocrine pathophysiological abnormalities, the etiology and a clear pathophysiology remains unclear. The gut microbiome gained much attention in the last decade with manifold implications in health and disease. Here we review the current state of knowledge on the interplay between ME/CFS and the microbiome, to identify potential diagnostic or interventional approaches, and propose areas where further research is needed.

We iteratively selected and elaborated on key theories about a correlation between microbiome state and ME/CFS pathology, developing further hypotheses. Based on the literature we hypothesize that antibiotic use throughout life favours an intestinal microbiota composition which might be a risk factor for ME/CFS. Main proposed pathomechanisms include gut dysbiosis, altered gut-brain axis activity, increased gut permeability with concomitant bacterial translocation and reduced levels of short-chain-fatty acids, D-lactic acidosis, an abnormal tryptophan metabolism and low activity of the kynurenine pathway. We review options for microbiome manipulation in ME/CFS patients including probiotic and dietary interventions as well as fecal microbiota transplantations. Beyond increasing gut permeability and bacterial translocation, specific dysbiosis may modify fermentation products, affecting peripheral mitochondria. Considering the gut-brain axis we strongly suspect that the microbiome may contribute to neurocognitive impairments of ME/CFS patients.

Further larger studies are needed, above all to clarify whether D-lactic acidosis and early-life antibiotic use may be part of ME/CFS etiology and what role changes in the tryptophan metabolism might play. An association between the gut microbiome and the disease ME/CFS is plausible. As causality remains unclear, we recommend longitudinal studies. Activity levels, bedridden hours and disease progression should be compared to antibiotic exposure, drug intakes and alterations in the composition of the microbiota. The therapeutic potential of fecal microbiota transfer and of targeted dietary interventions should be systematically evaluated.

Source: König RS, Albrich WC, Kahlert CR, Bahr LS, Löber U, Vernazza P, Scheibenbogen C, Forslund SK. The Gut Microbiome in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS). Front Immunol. 2022 Jan 3;12:628741. doi: 10.3389/fimmu.2021.628741. PMID: 35046929; PMCID: PMC8761622. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8761622/ (Full text)