Tag: long covid pathogenesis

Long COVID and post-acute sequelae of SARS-CoV-2 pathogenesis and treatment: A Keystone Symposia report

Abstract:

In 2023, the Keystone Symposia held the first international scientific conference convening research leaders investigating the pathology of post-acute sequelae of COVID-19 (PASC) or Long COVID, a growing and urgent public health priority. In this report, we present insights from the talks and workshops presented during this meeting and highlight key themes regarding what researchers have discovered regarding the underlying biology of PASC and directions toward future treatment.

Several themes have emerged in the biology, with inflammation and other immune alterations being the most common focus, potentially related to viral persistence, latent virus reactivation, and/or tissue damage and dysfunction, especially of the endothelium, nervous system, and mitochondria.

In order to develop safe and effective treatments for people with PASC, critical next steps should focus on the replication of major findings regarding potential mechanisms, disentangling pathogenic mechanisms from downstream effects, development of cellular and animal models, mechanism-focused randomized, placebo-controlled trials, and closer collaboration between people with lived experience, scientists, and other stakeholders.

Ultimately, by learning from other post-infectious syndromes, the knowledge gained may help not only those with PASC/Long COVID, but also those with other post-infectious syndromes.

Source: Matthew S. Durstenfeld, Shannon Weiman, Michael Holtzman, Catherine Blish, Resia Pretorius, Steven G. Deeks. Long COVID and post-acute sequelae of SARS-CoV-2 pathogenesis and treatment: A Keystone Symposia report. First published: 09 April 2024 https://doi.org/10.1111/nyas.15132 https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.15132 (Full text)

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

ACE-2-like enzymatic activity is associated with immunoglobulin in COVID-19 patients

Abstract:

Many mechanisms responsible for COVID-19 pathogenesis are well-established, but COVID-19 includes features with unclear pathogenesis, such as autonomic dysregulation, coagulopathies, and high levels of inflammation. The receptor for the SARS-CoV-2 spike protein receptor-binding domain (RBD) is angiotensin-converting enzyme 2 (ACE2). We hypothesized that some COVID-19 patients may develop antibodies that have a negative molecular image of RBD sufficiently similar to ACE2 to yield ACE2-like catalytic activity-ACE2-like abzymes.

To explore this hypothesis, we studied patients hospitalized with COVID-19 who had plasma samples available obtained about 7 days after admission. ACE2 is a metalloprotease that requires Zn2+ for activity. However, we found that the plasma from some patients studied could specifically cleave a synthetic ACE2 peptide substrate, even though the plasma samples were collected using disodium EDTA anticoagulant. When we spiked plasma with synthetic ACE2, no ACE2 substrate cleavage activity was observed unless Zn2+ was added or the plasma was diluted to decrease EDTA concentration.

After processing samples by 100 kDa size exclusion columns and protein A/G adsorption, which depleted immunoglobulin by >99.99%, the plasma samples did not cleave the ACE2 substrate peptide. The data suggest that some patients with COVID-19 develop antibodies with abzyme-like activity capable of cleaving synthetic ACE2 substrate. Since abzymes can exhibit promiscuous substrate specificities compared to the enzyme whose active site image they resemble, and since proteolytic cascades regulate many physiologic processes, anti-RBD abzymes may contribute to some otherwise obscure COVID-19 pathogenesis.

Importance: We provide what we believe to be the first description of angiotensin-converting enzyme 2 (ACE2)-like enzymatic activity associated with immunoglobulin in COVID-19 patients. COVID-19 includes many puzzling clinical features that have unclear pathogenesis, including a hyperinflammatory state, abnormalities of the clotting cascade, and blood pressure instability.

We hypothesized that some patients with COVID-19 patients may produce antibodies against SARS-CoV-2 with enzymatic activity, or abzymes, that target important proteolytic regulatory cascades. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein binds ACE2 on the surface of the future host cell. This means that the RBD has a negative molecular image of ACE2.

We hypothesized that some antibodies produced against the RBD would have, in turn, a negative molecular image of the RBD sufficiently similar to ACE2 to have ACE2-like catalytic activity. In other words, some anti-RBD antibodies would be ACE2-like abzymes. Abzymes elicited by SARS-CoV-2 infection have the potential to affect host physiology.

Source: Song Y, Myers R, Mehl F, Murphy L, Brooks B, Wilson JM, Kadl A, Woodfolk J, Zeichner SL. ACE-2-like enzymatic activity is associated with immunoglobulin in COVID-19 patients. mBio. 2024 Mar 19:e0054124. doi: 10.1128/mbio.00541-24. Epub ahead of print. PMID: 38501835. https://journals.asm.org/doi/10.1128/mbio.00541-24 (Full text)

Iron dysregulation and inflammatory stress erythropoiesis associates with long-term outcome of COVID-19

Abstract:

Persistent symptoms following SARS-CoV-2 infection are increasingly reported, although the drivers of post-acute sequelae (PASC) of COVID-19 are unclear. Here we assessed 214 individuals infected with SARS-CoV-2, with varying disease severity, for one year from COVID-19 symptom onset to determine the early correlates of PASC.

A multivariate signature detected beyond two weeks of disease, encompassing unresolving inflammation, anemia, low serum iron, altered iron-homeostasis gene expression and emerging stress erythropoiesis; differentiated those who reported PASC months later, irrespective of COVID-19 severity. A whole-blood heme-metabolism signature, enriched in hospitalized patients at month 1-3 post onset, coincided with pronounced iron-deficient reticulocytosis. Lymphopenia and low numbers of dendritic cells persisted in those with PASC, and single-cell analysis reported iron maldistribution, suggesting monocyte iron loading and increased iron demand in proliferating lymphocytes.

Thus, defects in iron homeostasis, dysregulated erythropoiesis and immune dysfunction due to COVID-19 possibly contribute to inefficient oxygen transport, inflammatory disequilibrium and persisting symptomatology, and may be therapeutically tractable.

Source: Hanson AL, Mulè MP, Ruffieux H, Mescia F, Bergamaschi L, Pelly VS, Turner L, Kotagiri P; Cambridge Institute of Therapeutic Immunology and Infectious Disease–National Institute for Health Research (CITIID–NIHR) COVID BioResource Collaboration; Göttgens B, Hess C, Gleadall N, Bradley JR, Nathan JA, Lyons PA, Drakesmith H, Smith KGC. Iron dysregulation and inflammatory stress erythropoiesis associates with long-term outcome of COVID-19. Nat Immunol. 2024 Mar;25(3):471-482. doi: 10.1038/s41590-024-01754-8. Epub 2024 Mar 1. PMID: 38429458; PMCID: PMC10907301. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10907301/ (Full text)

Altered mitochondrial respiration in peripheral blood mononuclear cells of post-acute sequelae of SARS-CoV-2 infection

Abstract:

Peripheral blood mononuclear cells (PBMC) mitochondrial respiration was measured ex vivo from participants without a history of COVID (n = 19), with a history of COVID and full recovery (n = 20), and with PASC (n = 20). Mean mitochondrial basal respiration, ATP-linked respiration, maximal respiration, spare respiration capacity, ATP-linked respiration, and non-mitochondrial respiration were highest in COVID + PASC+ (p ≤ 0.04). Every unit increase in non-mitochondrial respiration, ATP-linked respiration, basal respiration, spare respiration capacity, and maximal respiration increased the predicted odds of PASC between 1 % and 6 %. Mitochondrial dysfunction in PBMCs may be contributing to the etiology of PASC.

Source: Dirajlal-Fargo S, Maison DP, Durieux JC, Andrukhiv A, Funderburg N, Ailstock K, Gerschenson M, Mccomsey GA. Altered mitochondrial respiration in peripheral blood mononuclear cells of post-acute sequelae of SARS-CoV-2 infection. Mitochondrion. 2024 Feb 8:101849. doi: 10.1016/j.mito.2024.101849. Epub ahead of print. PMID: 38341012. https://www.sciencedirect.com/science/article/pii/S1567724924000072 (Full text)

Early immune factors associated with the development of post-acute sequelae of SARS-CoV-2 infection in hospitalized and non-hospitalized individuals

Abstract:

Background: Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to post-acute sequelae of SARS-CoV-2 (PASC) that can persist for weeks to years following initial viral infection. Clinical manifestations of PASC are heterogeneous and often involve multiple organs. While many hypotheses have been made on the mechanisms of PASC and its associated symptoms, the acute biological drivers of PASC are still unknown.

Methods: We enrolled 494 patients with COVID-19 at their initial presentation to a hospital or clinic and followed them longitudinally to determine their development of PASC. From 341 patients, we conducted multi-omic profiling on peripheral blood samples collected shortly after study enrollment to investigate early immune signatures associated with the development of PASC.

Results: During the first week of COVID-19, we observed a large number of differences in the immune profile of individuals who were hospitalized for COVID-19 compared to those individuals with COVID-19 who were not hospitalized. Differences between individuals who did or did not later develop PASC were, in comparison, more limited, but included significant differences in autoantibodies and in epigenetic and transcriptional signatures in double-negative 1 B cells, in particular.

Conclusions: We found that early immune indicators of incident PASC were nuanced, with significant molecular signals manifesting predominantly in double-negative B cells, compared with the robust differences associated with hospitalization during acute COVID-19. The emerging acute differences in B cell phenotypes, especially in double-negative 1 B cells, in PASC patients highlight a potentially important role of these cells in the development of PASC.

Source: Leung JM, Wu MJ, Kheradpour P, Chen C, Drake KA, Tong G, Ridaura VK, Zisser HC, Conrad WA, Hudson N, Allen J, Welberry C, Parsy-Kowalska C, Macdonald I, Tapson VF, Moy JN, deFilippi CR, Rosas IO, Basit M, Krishnan JA, Parthasarathy S, Prabhakar BS, Salvatore M, Kim CC. Early immune factors associated with the development of post-acute sequelae of SARS-CoV-2 infection in hospitalized and non-hospitalized individuals. Front Immunol. 2024 Jan 22;15:1348041. doi: 10.3389/fimmu.2024.1348041. PMID: 38318183; PMCID: PMC10838987. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10838987/ (Full text)

Role of Ferroptosis in the Progression of COVID-19 and the Development of Long COVID

Abstract:

Objectives: To examine the role of ferroptosis on the pathogenesis and progression of COVID-19.

Materials and methods: A total of 127 patients who were hospitalized for COVID-19 were categorized into two groups according to the intensity of oxygen therapy (high-flow or low-flow). Clinical characteristics, laboratory parameters, plasma markers, and peripheral blood mononuclear cell (PBMC) markers were measured at baseline and one or two weeks after treatment. Telephone follow-up was performed 3 months after discharge to assess long COVID.

Results: Patients receiving high-flow oxygen therapy had greater levels of neutrophils; D-dimer; C reactive protein; procalcitonin; plasma protein levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL-17, and acyl-CoA synthetase long-chain family member 4 (ACSL4); and PBMC mRNA level of TNF-α; but had lower levels of lymphocytes and plasma glutathione peroxidase 4 (GPX4). There were negative correlations of plasma GPX4 and cystine/glutamate transporter-11 (SLC7A11) with TNF-α, IL-6, and IL-17, and positive correlations of ACSL4 with inflammatory markers in plasma and PBMCs. The plasma levels of TNF-α, IL-6, IL-17, and ACSL4 were significantly lower after treatment than at baseline, but there were higher post-treatment levels of lymphocytes, GPX4, and SLC7A11. Patients with long COVID had a lower baseline level of plasma SLC7A11.

Conclusion: Ferroptosis is activated during the progression of COVID-19, and a low baseline level of a ferroptosis marker (SLC7A11) may indicate an increased risk for long COVID-19. Ferroptosis has potential as a clinical indicator of long COVID and as a therapeutic target.

Source: Zhao W, Wang S, Han Y, Zhang H, Cao J, Dong S, Li D, Lei M, Liu C, Gao Y. Role of Ferroptosis in the Progression of COVID-19 and the Development of Long COVID. Curr Med Chem. 2024 Jan 3. doi: 10.2174/0109298673281662231208102354. Epub ahead of print. PMID: 38310391. https://pubmed.ncbi.nlm.nih.gov/38310391/

Explaining Long COVID: A Pioneer Cross-Sectional Study Supporting the Endocrine Hypothesis

Abstract:

Context: In some patients, symptoms may persist after COVID-19, defined as long COVID. Its pathogenesis is still debated and many hypotheses have been raised.

Objective: Our primary objective was to evaluate the corticotroph and somatotroph functions of patients previously infected with SARS-CoV-2 and experiencing post–COVID-19 syndrome to detect any deficiencies that may explain long COVID.

Methods: A cross-sectional study was conducted including patients who had previously contracted SARS-CoV-2 with a postinfection period of 3 months or less to 15 months, divided into 2 groups. The first group (G1) comprised fully recovered patients, while the second group (G2) included patients experiencing long COVID. The primary outcome was the comparison of corticotroph and somatotroph functions.

Results: A total of 64 patients were divided into 2 groups, each consisting of 32 patients. G2 exhibited more frequently anterior pituitary deficits compared to G1 (P = .045): for the corticotroph axis (G1: 6.3% vs G2: 28.1%) and for the somatotroph axis (G1: 31.3% vs G2: 59.4%). Baseline cortisol level was significantly lower in G2 (G1: 13.37 µg/dL vs G2: 11.59 µg/dL) (P = .045). The peak cortisol level was also lower in G2 (G1: 23.60 µg/dL vs G2: 19.14 µg/dL) (P = .01). For the somatotroph axis, the insulin growth factor-1 level was lower in G2 (G1: 146.03 ng/mL vs G2: 132.25 ng/mL) (P = .369). The peak growth hormone level was also lower in G2 (G1: 4.82 ng/mL vs G2: 2.89 ng/mL) (P = .041).

Conclusion: The results showed that long COVID patients in our cohort were more likely to have anterior pituitary deficiencies. The endocrine hypothesis involving anterior pituitary insufficiency can be considered to explain long COVID.

Source: Taieb Ach, Nassim Ben Haj Slama, Asma Gorchane, Asma Ben Abdelkrim, Meriem Garma, Nadia Ben Lasfar, Foued Bellazreg, Widéd Debbabi, Wissem Hachfi, Molka Chadli Chaieb, Monia Zaouali, Amel Letaief, Koussay Ach, Explaining Long COVID: A Pioneer Cross-Sectional Study Supporting the Endocrine Hypothesis, Journal of the Endocrine Society, Volume 8, Issue 3, March 2024, bvae003, https://doi.org/10.1210/jendso/bvae003 https://academic.oup.com/jes/advancearticle/doi/10.1210/jendso/bvae003/7517018 (Full text)

Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden

Abstract:

Cardiovascular autonomic dysfunction (CVAD) is a malfunction of the cardiovascular system caused by deranged autonomic control of circulatory homeostasis. CVAD is an important component of post-COVID-19 syndrome, also termed long COVID, and might affect one-third of highly symptomatic patients with COVID-19. The effects of CVAD can be seen at both the whole-body level, with impairment of heart rate and blood pressure control, and in specific body regions, typically manifesting as microvascular dysfunction.

Many severely affected patients with long COVID meet the diagnostic criteria for two common presentations of CVAD: postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. CVAD can also manifest as disorders associated with hypotension, such as orthostatic or postprandial hypotension, and recurrent reflex syncope. Advances in research, accelerated by the COVID-19 pandemic, have identified new potential pathophysiological mechanisms, diagnostic methods and therapeutic targets in CVAD. For clinicians who daily see patients with CVAD, knowledge of its symptomatology, detection and appropriate management is more important than ever.

In this Review, we define CVAD and its major forms that are encountered in post-COVID-19 syndrome, describe possible CVAD aetiologies, and discuss how CVAD, as a component of post-COVID-19 syndrome, can be diagnosed and managed. Moreover, we outline directions for future research to discover more efficient ways to cope with this prevalent and long-lasting condition.

Key points:

  • Cardiovascular autonomic dysfunction (CVAD), in particular postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia, are among the most frequent and distinct phenotypes of post-COVID-19 syndrome; one-third of highly symptomatic patients can be affected.
  • CVAD arises from a malfunction of the autonomic control of the circulation, and can involve failure or inadequate or excessive activation of the sympathetic and parasympathetic components of the autonomic nervous system.
  • As well as global circulatory disturbances, CVAD in post-COVID-19 syndrome can manifest as microvascular and endothelial dysfunction, with local symptoms such as headache, brain fog, chest pain, dyspnoea and peripheral circulatory symptoms, including skin discolouration, oedema, Raynaud-like phenomena, and heat and cold intolerance.
  • A structured diagnostic work-up based on a detailed patient history, cardiovascular autonomic testing, long-term electrocardiogram and blood-pressure monitoring, and ancillary cardiac and peripheral vascular tests will lead to an appropriate diagnosis.
  • Management of CVAD in post-COVID-19 syndrome should involve a correct diagnosis, patient education, and both non-pharmacological and pharmacological methods; a tailored exercise training programme, blood volume expansion and compression garments are especially effective.
  • Pharmacological approaches target heart rate control, blood volume expansion, promotion of vasoconstriction and venoconstriction, and reduction of hyperadrenergic drive.

Source: Fedorowski, A., Fanciulli, A., Raj, S.R. et al. Cardiovascular autonomic dysfunction in post-COVID-19 syndrome: a major health-care burden. Nat Rev Cardiol (2024). https://doi.org/10.1038/s41569-023-00962-3 https://www.nature.com/articles/s41569-023-00962-3

Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/anti-pathogen agent in a retrospective case series

Highlights:

• Both Long COVID and ME/CFS are characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα.

• In a small Long COVID and ME/CFS case series, patients’ immune deficiency and health improve during treatment period with a nebulized antioxidant, anti-pathogen and immune-modulatory pharmacological agent.

• This work provides evidence of a useful biomarker, CD8 T-cell dysfunction reminiscent of T cell exhaustion, that may assist diagnosis and have utility for tracking disease outcome during therapy, including response to a potential new treatment.

Abstract:

Background: Patients with post-acute sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC, i.e., Long COVID) have a symptom complex highly analogous to many features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggesting they may share some aspects of pathogenesis in these similar disorders. ME/CFS is a complex disease affecting numerous organ systems and biological processes and is often preceded by an infection-like episode. It is postulated that the chronic manifestations of illness may result from an altered host response to infection or inability to resolve inflammation, as is being reported in Long COVID. The immunopathogenesis of both disorders is still poorly understood. Here, we show data that suggest Long COVID and ME/CFS may be due to an aberrant response to an immunological trigger-like infection, resulting in a dysregulated immune system with CD8 T-cell dysfunction reminiscent of some aspects of T-cell clonal exhaustion, a phenomenon associated with oxidative stress. As there is an urgent need for diagnostic tools and treatment strategies for these two related disabling disorders, here, in a retrospective case series, we have also identified a potential nebulized antioxidant/anti-pathogen treatment that has evidence of a good safety profile. This nebulized agent is comprised of five ingredients previously reported individually to relieve oxidative stress, attenuate NF-κB signaling, and/or to act directly to inhibit pathogens, including viruses. Administration of this treatment by nebulizer results in rapid access of small doses of well-studied antioxidants and agents with anti-pathogen potential to the lungs; components of this nebulized agent are also likely to be distributed systemically, with potential to enter the central nervous system.

Methods and Findings: We conducted an analysis of CD8 T-cell function and severity of symptoms by self-report questionnaires in ME/CFS, Long COVID and healthy controls. We developed a CD8 T-cell functional assay, assessing CD8 T-cell dysfunction by intracellular cytokine staining (ICS) in a group of ME/CFS (n = 12) and Long COVID patients (n = 8), comparing to healthy controls (HC) with similar age and sex (n = 10). Magnet-enriched fresh CD8 T-cells in both patient groups had a significantly diminished capacity to produce both cytokines, IFNγ or TNFα, after PMA stimulation when compared to HC. The symptom severity questionnaire showed similar symptom profiles for the two disorders. Fortuitously, through a retrospective case series, we were able to examine the ICS and questionnaire data of 4 ME/CFS and 4 Long COVID patients in conjunction with their treatment (3–15 months). In parallel with the treatment pursued electively by participants in this retrospective case series, there was an increase in CD8 T-cell IFNγ and TNFα production and a decrease in overall self-reported symptom severity score by 54%. No serious treatment-associated side effects or laboratory anomalies were noted in these patients.

Conclusions: Here, in this small study, we present two observations that appear potentially fundamental to the pathogenesis and treatment of Long COVID and ME/CFS. The first is that both disorders appear to be characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα. The second is that in a small retrospective Long COVID and ME/CFS case series, this immune dysfunction and patient health improved in parallel with treatment with an immunomodulatory, antioxidant pharmacological treatment with anticipated anti-pathogen activity. This work provides evidence of the potential utility of a biomarker, CD8 T-cell dysfunction, and suggests the potential for benefit from a new nebulized antioxidant/anti-pathogen treatment. These immune biomarker data may help build capacity for improved diagnosis and tracking of treatment outcomes during clinical trials for both Long COVID and ME/CFS while providing clues to new treatment avenues that suggest potential efficacy for both conditions.

Source: Gil, A., Hoag, G.E., Salerno, J.P., Hornig, M., Klimas, N., Selin, L.K. Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/antipathogen agent in a retrospective case series. Brain, Behavior, & Immunity – Health (2024), doi: https://doi.org/10.1016/j.bbih.2023.100720 https://www.sciencedirect.com/science/article/pii/S2666354623001345 (Full text)