Tag: antibodies

COVID-19 Antibody Discovery Could Explain Long COVID

Press Release:

UVA Health researchers have discovered a potential explanation for some of the most perplexing mysteries of COVID-19 and long COVID. The surprising findings could lead to new treatments for the difficult acute effects of COVID-19, long COVID and possibly other viruses.

Researchers led by UVA’s Steven L. Zeichner, MD, PhD, found that COVID-19 may prompt some people’s bodies to make antibodies that act like enzymes that the body naturally uses to regulate important functions – blood pressure, for example. Related enzymes also regulate other important body functions, such as blood clotting and inflammation.

Doctors may be able to target these “abzymes” to stop their unwanted effects. If abzymes with rogue activities are also responsible for some of the features of long COVID, doctors could target the abzymes to treat the difficult and sometimes mysterious symptoms of COVID-19 and long COVID at the source, instead of merely treating the downstream symptoms.

“Some patients with COVID-19 have serious symptoms and we have trouble understanding their cause. We also have a poor understanding of the causes of long COVID,” said Zeichner, a pediatric infectious disease expert at UVA Children’s. “Antibodies that act like enzymes are called ‘abzymes.’ Abzymes are not exact copies of enzymes and so they work differently, sometimes in ways that the original enzyme does not. If COVID-19 patients are making abzymes, it is possible that these rogue abzymes could harm many different aspects of physiology. If this turns out to be true, then developing treatments to deplete or block the rogue abzymes could be the most effective way to treat the complications of COVID-19.”

Understanding COVID-19 Abzymes

SARS-CoV-2, the virus that causes COVID, has protein on its surface called the Spike protein. When the virus begins to infect a cell, the Spike protein binds a protein called Angiotensin Converting Enzyme 2, or ACE2, on the cell’s surface. ACE2’s normal function in the body is to help regulate blood pressure; it cuts a protein called angiotensin II to make a derivative protein called angiotensin 1-7. Angiotensin II constricts blood vessels, raising blood pressure, while angiotensin 1-7 relaxes blood vessels, lowering blood pressure.

Zeichner and his team thought that some patients might make antibodies against the Spike protein that looked enough like ACE2 so that the antibodies also had enzymatic activity like ACE2, and that is exactly what they found.

Recently, other groups have found that some patients with long COVID have problems with their coagulation systems and with another system called “complement.” Both the coagulation system and the complement system are controlled by enzymes in the body that cut other proteins to activate them. If patients with long COVID make abzymes that activate proteins that control processes such as coagulation and inflammation, that could explain the source of some of the long COVID symptoms and why long COVID symptoms persist even after the body has cleared the initial infection. It also may explain rare side effects of COVID-19 vaccination.

To determine if antibodies could be having unexpected effects in COVID patients, Zeichner and his collaborators examined plasma samples collected from 67 volunteers with moderate or severe COVID on or around day 7 of their hospitalization. The researchers compared what they found with plasma collected in 2018, prior to the beginning of the pandemic. The results showed that a small subset of the COVID patients had antibodies that acted like enzymes.

While our understanding of the potential role of abzymes in COVID-19 is still in its early stages, enzymatic antibodies have already been detected in certain cases of HIV, Zeichner notes. That means there is precedent for a virus to trigger abzyme formation. It also suggests that other viruses may cause similar effects.

Zeichner, who is developing a universal coronavirus vaccine, expects UVA’s new findings will renew interest in abzymes in medical research. He also hopes his discovery will lead to better treatments for patients with both acute COVID-19 and long COVID.

“We now need to study pure versions of antibodies with enzymatic activity to see how abzymes may work in more detail, and we need to study patients who have had COVID-19 who did and did not develop long COVID,” he said. “There is much more work to do, but I think we have made a good start in developing a new understanding of this challenging disease that has caused so much distress and death around the world. The first step to developing effective new therapies for a disease is developing a good understanding of the disease’s underlying causes, and we have taken that first step.”

Findings Published

The researchers have published their findings in the scientific journal mBio, a publication of the American Society for Microbiology. The research team consisted of Yufeng Song, Regan Myers, Frances Mehl, Lila Murphy, Bailey Brooks, and faculty members from the Department of Medicine, Jeffrey M. Wilson, Alexandra Kadl, Judith Woodfolk.

“It’s great to have such talented and dedicated colleagues here at UVA who are excited about working on new and unconventional research projects,” said Zeichner.

Zeichner is the McClemore Birdsong Professor in the University of Virginia School of Medicine’s Departments of Pediatrics and Microbiology, Immunology and Cancer Biology; the director of the Pendleton Pediatric Infectious Disease Laboratory; and part of UVA Children’s Child Health Research Center.

The abzyme research was supported by UVA, including the Manning Fund for COVID-19 Research at UVA; the Ivy Foundation; the Pendleton Laboratory Fund for Pediatric Infectious Disease Research; a College Council Minerva Research Grant; the Coulter Foundation; and the National Institutes of Health’s National Institute of Allergy and Infection Diseases, grant R01 AI176515. Additional support came from the HHV-6 Foundation.

Source: UVA Health News

Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn’s Disease and chronic fatigue syndrome

Abstract:

Background: Patients with Crohn’s disease (CD) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) exhibit elevated antibody responses against gut microbiota flagellins. However, flagellin-specific antibody repertoires and functional roles in the diseases remain incompletely understood. Bacterial flagellins can be categorized into three types depending on their interaction with toll-like receptor 5 (TLR5): (1) “stimulator” and (2) “silent” flagellins, binding TLR5 through a conserved N-terminal motif, with only stimulators activating TLR5 due to a specific C-terminal domain; (3) “evader” flagellins of pathogens, which circumvent TLR5 activation via mutated N-terminal TLR5 binding motifs. Here we studied the characteristics, epitope binding, and sequence (dis)similarity of anti-flagellin antibody responses in CD and ME/CFS.
Methods: Since conventional antibody profiling methods like enzyme-linked immunosorbent assays [ELISAs] do not allow for large-scale measurements of antibody repertoires, we leveraged phage-display immunoprecipitation sequencing (PhIP-Seq) to characterize 344,000 rationally selected peptide antigens in 256 patients with CD, 40 patients with ME/CFS and in two equally sized groups of age- and sex-matched healthy controls from population-based cohorts in the Netherlands and U.K., respectively. Different sequence alignment strategies were employed to compare flagellin peptide structures with observed antibody-bound flagellin peptide reactivity.
Results: Both patients with CD and ME/CFS exhibited elevated antibody responses against distinct regions of flagellin peptides compared to healthy individuals (P<0.001). N-terminal binding to Lachnospiraceae flagellins was comparable in both diseases, while C-terminal binding was more prevalent in CD. N-terminal antibody-bound flagellin sequences were similar across CD and ME/CFS, resembling ‘stimulator’ and ‘silent’ flagellins more than evaders. However, C-terminal antibody-bound flagellins showed higher resemblance to stimulator than to silent flagellins in CD, but not in ME/CFS. This group of antibody-bound flagellins was exclusively identified in a subset (10-20%) of patients with CD and characterized by its strong overrepresentation (exceeding 20-fold), underscoring its potential significance in distinguishing pathophysiologic subtypes of CD.
Conclusion: Antibody binding to the N-terminal domain of stimulator and silent flagellins may impact TLR5 activation in both CD and ME/CFS patients. Furthermore, elevated antibody binding to the C-terminal domain of stimulator flagellins in CD may explain pathophysiological differences between diseases. Our results highlight the diagnostic potential of these antibody responses and their impact on innate/adaptive immunity balance.

Source: A R Bourgonje, N V Hörstke, M Fehringer, G Innocenti, T Vogl, DOP27 Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn’s Disease and chronic fatigue syndrome, Journal of Crohn’s and Colitis, Volume 18, Issue Supplement_1, January 2024, Page i122, https://doi.org/10.1093/ecco-jcc/jjad212.0067 https://academic.oup.com/ecco-jcc/article/18/Supplement_1/i122/7586226 (Full text available as PDF file)

THE ROLE OF α7 NICOTINIC ACETYLCHOLINE RECEPTORS IN POST-ACUTE SEQUELAE OF COVID-19

Abstract:

Post-Acute Sequelae of COVID-19 or Long COVID becomes evident some weeks to months following acute COVID-19. Symptoms include cognitive impairment and varying degrees of memory loss with no definitive etiologies or efficacious therapies forthcoming even after four years of the SARS-Cov2 pandemic virus. The aim of this review is to demonstrate the important role of α7 nicotinic acetylcholine receptors in both acute COVID-19 and Long COVID.

Evidence presented implicates immune mechanisms stimulated by SARS-Cov-2 S-protein fragment 674-685 that possesses homology with α7-specific ligands. Cognitive dysfunctions observed in Long COVID patients may be derived from anti-idiotypic α7-specific antibodies stimulated by (674-685)-specific antibodies. Therapeutic interventions capable of neutralizing these antibodies and restoring full functions of α7 nicotinic acetylcholine receptors appear to be of paramount importance in post-acute sequelae of COVID-19.

Source: Skok M. THE ROLE OF α7 NICOTINIC ACETYLCHOLINE RECEPTORS IN POST-ACUTE SEQUELAE OF COVID-19. Int J Biochem Cell Biol. 2024 Jan 11:106519. doi: 10.1016/j.biocel.2024.106519. Epub ahead of print. PMID: 38218363. https://www.sciencedirect.com/science/article/abs/pii/S1357272524000104

Role of pharmacological activity of autoantibodies in ME/CFS

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a condition characterised by extreme fatigue, memory impairment, pain and other symptoms that vary from patient to patient. It affects about 0.9% of the population and is often triggered by an acute viral or bacterial infection, such as Epstein-Barr virus. The underlying physiological and molecular basis of ME/CFS is unknown, and no effective treatments exist.

One proposed mechanism is that the blood flow is altered by autoantibodies against receptors involved in blood flow regulation. Antibodies are generated by the immune system to recognise intruders and under normal conditions, our immune system is trained not to attack our own tissues. However, during a severe infection, the immune system adopts an “all hands on deck” approach, which results in some of the newly-produced antibodies escaping quality control and targeting our own tissues, autoantibodies. Receptors regulation blood flow are located in walls of blood vessels and cause a blood vessel to dilate or contract as the demand for oxygen and nutrients to tissues such as the brain or muscles changes. Research has found increased levels of these autoantibodies in ME/CFS patients and initial trials removing these autoantibodies from the blood using a technique called immunoadsorption have shown improvement in symptoms.

In this project, we will test the hypothesis that autoantibodies can activate or inhibit the receptors responsible for the blood flow regulation, in a similar way medical drugs are used to regulate blood pressure.
We aim to profile serum samples from 325 ME/CFS patients and 130 healthy individuals to determine the presence of autoantibodies against all thirty receptors involved in blood pressure regulation. Importantly, we will study the ability of autoantibodies detected in each sample to activate or inhibit these receptors in order to test the hypothesis that the activity of these autoantibodies is a decisive factor in the disease.
If our hypothesis is correct, we will be able to develop an accurate blood test that may be able to detect ME/CFS earlier or to independently confirm the diagnosis. Ultimately, we hope that these results may also indicate a possible route for therapeutic intervention to counteract the effects of autoantibodies and alleviate the ME/CFS symptoms using a combination of already existing drugs, specific for each individual case.

 

Technical Summary:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a condition of extreme tiredness and brain fog, often triggered by an acute infection. Its prevalence is ca 0.9% and here is no effective treatment. Competing theories for the root cause of ME/CFS include metabolic or redox homeostasis disruption, and presence of autoantibodies (AABs) against G protein coupled receptors (GPCRs) involved in regulation of blood flow.
Triggered by acute infection, autoimmunity is a result of reduced immuno-vigilance during severe infections, when an “all hands on deck” approach confers survival advantage. About 30% of ME/CFS patients show increased titre of autoantibodies against beta2-adrenoceptor and M3/4 muscarinic receptors controlling vasodilation/vasoconstriction, but this could become higher if all 30 receptors controlling blood flow would be taken into account.
In this project, we will test a hypothesis that the pharmacological activity of AABs against GPCRs is the key to their involvement in ME/CFS. Similar to medical drugs, AABs can be stimulatory (agonistic) or inhibitory (antagonistic) and induce a therapeutic or an undesired side effect.
We will profile 325 patient samples and 130 control plasma samples for AABs and their pharmacological activity using a state-of-the art GPCR drug screening pipeline we have established, against all 30 GPCRs involved in blood pressure regulation. We also have machine learning expertise that would allow us to interpret this extensive dataset, extract the most salient features. This will advance the understanding of the molecular basis of ME/CFS and could form the basis of a robust diagnostic blood test for ME/CFS. Ultimately, our findings may point in the direction of developing combination therapy using repurposed drugs to counteract the effects of autoantibodies and mitigate ME/CFS symptoms and stimulate the development of specific B-cell elimination strategy to cure ME/CFS.
Source: Lead Research Organisation: University of Nottingham, Department Name: School of Life Sciences. https://gtr.ukri.org/projects?ref=MR%2FY003667%2F1&pn=0&fetchSize=25&selectedSortableField=date&selectedSortOrder=ASC

Catalytic Antibodies May Contribute to Demyelination in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Here we report preliminary data demonstrating that some patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may have catalytic autoantibodies that cause the breakdown of myelin basic protein (MBP). We propose that these MBP-degradative antibodies are important to the pathophysiology of ME/CFS, particularly in the occurrence of white matter disease/demyelination. This is supported by magnetic resonance imagining studies that show these findings in patients with ME/CFS and could explain symptoms of nerve pain and muscle weakness.

In this work, we performed a series of experiments on patient plasma samples where we isolated and characterized substrate-specific antibodies that digest MBP. We also tested glatiramer acetate (copaxone), an FDA approved immunomodulator to treat multiple sclerosis, and found that it inhibits ME/CFS antibody digestion of MBP. Furthermore, we found that aprotinin, which is a specific serine protease inhibitor, specifically prevents breakdown of MBP while the other classes of protease inhibitors had no effect. This coincides with the published literature describing catalytic antibodies as having serine protease-like activity. Postpandemic research has also provided several reports of demyelination in COVID-19.

Because COVID-19 has been described as a trigger for ME/CFS, demyelination could play a bigger role in patient symptoms for those recently diagnosed with ME/CFS. Therefore, by studying proteolytic antibodies in ME/CFS, their target substrates, and inhibitors, a new mechanism of action could lead to better treatment and a possible cure for the disease.

Source: Jensen MA, Dafoe ML, Wilhelmy J, Cervantes L, Okumu AN, Kipp L, Nemat-Gorgani M, Davis RW. Catalytic Antibodies May Contribute to Demyelination in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Biochemistry. 2023 Nov 27. doi: 10.1021/acs.biochem.3c00433. Epub ahead of print. PMID: 38011893. https://pubs.acs.org/doi/10.1021/acs.biochem.3c00433 (Full text)

IgG Antibody Responses to Epstein-Barr Virus in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Their Effective Potential for Disease Diagnosis and Pathological Antigenic Mimicry

Abstract:

The diagnosis and the pathology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) remain under debate. However, there is a growing body of evidence for an autoimmune component in ME/CFS caused by the Epstein-Barr virus (EBV) and other viral infections.
In this work, we took advantage of a large public dataset on the IgG antibodies to 3,054 EBV peptides to understand whether these immune responses could be used as putative biomarkers for disease diagnosis and triggers of pathological autoimmunity in ME/CFS patients using healthy controls (HCs) as a comparator cohort. We then aimed at predicting disease status of study participants using a Super Learner algorithm targeting an accuracy of 85% when splitting data into train and test datasets.
When we compared data of all ME/CFS patients or data of a subgroup of these patients with non-infectious or unknown disease trigger to the dataset of HC, we could not find an antibody-based classifier that would meet the desired accuracy in the test dataset. In contrast, we could identify a 26-antibody classifier that could distinguish ME/CFS patients with an infectious disease trigger from HCs with 100% and 90% accuracies on the train and test sets, respectively.
We finally performed a bioinformatic analysis of the EBV peptides associated with these 26 antibodies. We found no correlation between the importance metric of the selected antibodies in the classifier and the maximal sequence homology between human proteins and each EBV peptide recognized by these antibodies.
In conclusion, these 26 antibodies against EBV have an effective potential for disease diagnosis of a subset of patients, but they are less likely to trigger pathological autoimmune responses that could explain the pathogenesis of ME/CFS.
Source: Fonseca, A.; Szysz, M.; Ly, H.T.; Cordeiro, C.; Sepúlveda, N. IgG Antibody Responses to Epstein-Barr Virus in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Their Effective Potential for Disease Diagnosis and Pathological Antigenic Mimicry. Preprints 2023, 2023111523. https://doi.org/10.20944/preprints202311.1523.v1 https://www.preprints.org/manuscript/202311.1523/v1 (Full text available as PDF file)

Neurologic sequelae of COVID-19 are determined by immunologic imprinting from previous coronaviruses

Abstract:

Coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health emergency. Although SARS-CoV-2 is primarily a respiratory pathogen, extra-respiratory organs, including the CNS, can also be affected. Neurologic symptoms have been observed not only during acute SARS-CoV-2 infection, but also at distance from respiratory disease, also known as long-COVID or neurological post-acute sequelae of COVID-19 (neuroPASC). The pathogenesis of neuroPASC is not well understood, but hypotheses include SARS-CoV-2-induced immune dysfunctions, hormonal dysregulations and persistence of SARS-CoV-2 reservoirs.

In this prospective cohort study, we used a high throughput systems serology approach to dissect the humoral response to SARS-CoV-2 (and other common coronaviruses: 229E, HKU1, NL63 and OC43) in the serum and CSF from 112 infected individuals who developed (n = 18) or did not develop (n = 94) neuroPASC. Unique SARS-CoV-2 humoral profiles were observed in the CSF of neuroPASC compared with serum responses. All antibody isotypes (IgG, IgM, IgA) and subclasses (IgA1-2, IgG1-4) were detected in serum, whereas CSF was characterized by focused IgG1 (and absence of IgM).

These data argue in favour of compartmentalized brain-specific responses against SARS-CoV-2 through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier, rather than intrathecal synthesis, where more diversity in antibody classes/subclasses would be expected.

Compared to individuals who did not develop post-acute complications following infection, individuals with neuroPASC had similar demographic features (median age 65 versus 66.5 years, respectively, P = 0.55; females 33% versus 44%, P = 0.52) but exhibited attenuated systemic antibody responses against SARS-CoV-2, characterized by decreased capacity to activate antibody-dependent complement deposition (ADCD), NK cell activation (ADNKA) and to bind Fcγ receptors. However, surprisingly, neuroPASC individuals showed significantly expanded antibody responses to other common coronaviruses, including 229E, HKU1, NL63 and OC43.

This biased humoral activation across coronaviruses was particularly enriched in neuroPASC individuals with poor outcome, suggesting an ‘original antigenic sin’ (or immunologic imprinting), where pre-existing immune responses against related viruses shape the response to the current infection, as a key prognostic marker of neuroPASC disease.

Overall, these findings point to a pathogenic role for compromised anti-SARS-CoV-2 responses in the CSF, likely resulting in incomplete virus clearance from the brain and persistent neuroinflammation, in the development of post-acute neurologic complications of SARS-CoV-2 infection.

Source: Spatola M, Nziza N, Jung W, Deng Y, Yuan D, Dinoto A, Bozzetti S, Chiodega V, Ferrari S, Lauffenburger DA, Mariotto S, Alter G. Neurologic sequelae of COVID-19 are determined by immunologic imprinting from previous coronaviruses. Brain. 2023 Oct 3;146(10):4292-4305. doi: 10.1093/brain/awad155. PMID: 37161609. https://academic.oup.com/brain/article/146/10/4292/7158783 (Full text)

Severity of neurological long-COVID symptoms correlates with increased level of autoantibodies targeting vasoregulatory and autonomic nervous system receptors

Abstract:

Background: The Long-COVID syndrome constitutes a plethora of persisting symptoms with neurological disorders being the most disabling ones. The pathogenesis of Long-COVID is currently under heavy scrutiny and existing data on the role of auto-immune reaction to G-protein coupled receptors (GPCR) are conflicting.

Methods: This monocentric, cross-sectional study included patients who suffered a mild to moderate SARS-CoV-2 infection up to 12 months prior to enrollment with (n = 72) or without (n = 58) Long-COVID diagnosis according to the German S1 guideline or with no known history of SARS-CoV-2 infection (n = 70). While autoantibodies towards the vasoregulation associated Adrenergic Receptor (ADR) B1 and B2 and the CNS and vasoregulation associated muscarinic acetylcholine receptor (CHR) M3 and M4 were measured by ELISA, neurological disorders were quantified by internationally standardized questionnaires.

Results: The prevalence and concentrations of evaluated autoantibodes were significantly higher in Long-COVID compared to the 2 other groups (p = 2.1*10−9) with a significantly higher number of patients with simultaneous detection of more than one autoantibody in Long-COVID group (p = 0.0419). Importantly, the overall inflammatory state was low in all 3 groups. ARB1 and ARB2 correlated negatively CERAD Trail Marking A and B (R ≤ −0.26, p ≤ 0.043), while CHRM3 correlated positively with Chadler Fatigue Scale (R = 0.37, p = 0.0087).

Conclusions: Concentrations of autoantibodies correlates to intensity of neurological disorders including psychomotor speed, visual search, attention, and fatigue.

Source: Felix S. Seibert, Ulrik Stervbo, Lea Wiemers, Sarah Skrzypczyk, Maximillian Hogeweg, Sebastian Bertram, Julia Kurek, Moritz Anft, Timm H. Westhoff, Nina Babel. Severity of neurological long-COVID symptoms correlates with increased level of autoantibodies targeting vasoregulatory and autonomic nervous system receptors. Autoimmunity Reviews,2023, 103445, ISSN 1568-9972. https://www.sciencedirect.com/science/article/abs/pii/S1568997223001799 (Full text)

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

Divergent Adaptive Immune Responses Define Two Types Of Long Covid

The role of adaptive immune responses in long COVID remains poorly understood, with contrasting hypotheses suggesting either an insufficient antiviral response or an excessive immune response associated with inflammatory damage. To address this issue, we set to characterize humoral and CD4+ T cell responses in long COVID patients prior to SARS-CoV-2 vaccination.

Long COVID patients who were seropositive (LC+, n=28) or seronegative (LC-, n=23) by spike ELISA assay were recruited based on (i) an initial SARS-CoV-2 infection documented by PCR or the conjunction of three major signs of COVID-19 and (ii) the persistence or resurgence of at least 3 symptoms for over 3 months. They were compared to COVID patients with resolved symptoms (RE, n=29) and uninfected control individuals (HD, n=29).

The spectrum of persistent symptoms proved similar in both long COVID groups, with a trend for a higher number of symptoms in the seronegative group (median=6 vs 4.5; P=0.01). The use a highly sensitive S-flow assay enabled the detection of low levels of SARS-CoV-2 spike-specific IgG in 22.7% of ELISA-seronegative long COVID (LC-) patients. In contrast, spike-specific IgG levels were uniformly high in the LC+ and RE groups.

Multiplexed antibody analyses to 30 different viral antigens showed that LC-patients had defective antibody responses to all SARS-CoV-2 proteins tested but had in most cases preserved responses to other viruses. A sensitive primary T cell line assay revealed low but detectable SARS-CoV-2-specific CD4 responses in 39.1% of LC-patients, while response frequencies were high in the LC+ and RE groups. Correlation analyses showed overall strong associations between humoral and cellular responses, with exceptions in the LC-group.

These findings provide evidence for two major types of antiviral immune responses in long COVID. Seropositive patients showed coordinated cellular and humoral responses at least as high as those of recovered patients. In contrast, ELISA-seronegative long COVID patients showed overall low antiviral responses, with detectable specific CD4+ T cells and/or antibodies in close to half of patients (52.2%). These divergent findings in patients sharing a comparable spectrum of persistent symptoms raise the possibility of multiple etiologies in long COVID.

Source: Jérôme Kervevan, Isabelle Staropoli, Dorsaf Slama, Raphaël Jeger-Madiot, Françoise Donnadieu, Delphine Planas, Marie-Pierre Pietri, Wiem Loghmari-Bouchneb, Motolete A. Tanah, Rémy Robinot, Faroudy Boufassa, Michael White, Dominique SALMON and Lisa A. Chakrabarti. Front. Immunol. Sec. Viral Immunology. Volume 14 – 2023 | doi: 10.3389/fimmu.2023.1221961 https://www.frontiersin.org/articles/10.3389/fimmu.2023.1221961/abstract