Tag: long covid immunology

Increased levels of inflammatory molecules in blood of Long COVID patients point to thrombotic endotheliitis

Abstract:

The prevailing hypotheses for the persistent symptoms of Long COVID have been narrowed down to immune dysregulation and autoantibodies, widespread organ damage, viral persistence, and fibrinaloid microclots (entrapping numerous inflammatory molecules) together with platelet hyperactivation. Here we demonstrate significantly increased concentrations of Von Willebrand Factor, platelet factor 4, serum amyloid A, alpha-2-antiplasmin E-selectin, and platelet endothelial cell adhesion molecule-1, in the soluble part of the blood.

It was noteworthy that the mean level of alpha-2-antiplasmin exceeded the upper limit of the laboratory reference range in Long COVID patients, and the other 5 were significantly elevated in Long COVID patients as compared to the controls. This is alarming if we take into consideration that a significant amount of the total burden of these inflammatory molecules has previously been shown to be entrapped inside fibrinolysis-resistant microclots (thus decreasing the apparent level of the soluble molecules). We also determined that by individually adding E-selectin and PECAM-1 to healthy blood, these molecules may indeed be involved in protein-protein interactions with plasma proteins (contributing to microclot formation) and platelet hyperactivation. This investigation was performed as a laboratory model investigation and the final exposure concentration of these molecules was chosen to mimic concentrations found in Long COVID.

We conclude that presence of microclotting, together with relatively high levels of six inflammatory molecules known to be key drivers of endothelial and clotting pathology, points to thrombotic endotheliitis as a key pathological process in Long COVID. This has implications for the choice of appropriate therapeutic options in Long COVID.

Source: Simone Turner, Caitlin Naidoo, Thomas Usher, Arneaux Kruger, Chantelle Venter, Gert J Laubscher, M Asad Khan, Douglas B Kell, Etheresia Pretorius. Increased levels of inflammatory molecules in blood of Long COVID patients point to thrombotic endotheliitis. medRxiv 2022.10.13.22281055; doi: https://doi.org/10.1101/2022.10.13.22281055 (Full text available as PDF file)

Neurogenesis is disrupted in human hippocampal progenitor cells upon exposure to serum samples from hospitalized COVID-19 patients with neurological symptoms

Abstract:

Coronavirus disease 2019 (COVID-19), represents an enormous new threat to our healthcare system and particularly to the health of older adults. Although the respiratory symptoms of COVID-19 are well recognized, the neurological manifestations, and their underlying cellular and molecular mechanisms, have not been extensively studied yet. Our study is the first one to test the direct effect of serum from hospitalised COVID-19 patients on human hippocampal neurogenesis using a unique in vitro experimental assay with human hippocampal progenitor cells (HPC0A07/03 C). We identify the different molecular pathways activated by serum from COVID-19 patients with and without neurological symptoms (i.e., delirium), and their effects on neuronal proliferation, neurogenesis, and apoptosis.

We collected serum sample twice, at time of hospital admission and approximately 5 days after hospitalization. We found that treatment with serum samples from COVID-19 patients with delirium (n = 18) decreased cell proliferation and neurogenesis, and increases apoptosis, when compared with serum samples of sex- and age-matched COVID-19 patients without delirium (n = 18). This effect was due to a higher concentration of interleukin 6 (IL6) in serum samples of patients with delirium (mean ± SD: 229.9 ± 79.1 pg/ml, vs. 32.5 ± 9.5 pg/ml in patients without delirium).

Indeed, treatment of cells with an antibody against IL6 prevented the decreased cell proliferation and neurogenesis and the increased apoptosis. Moreover, increased concentration of IL6 in serum samples from delirium patients stimulated the hippocampal cells to produce IL12 and IL13, and treatment with an antibody against IL12 or IL13 also prevented the decreased cell proliferation and neurogenesis, and the increased apoptosis. Interestingly, treatment with the compounds commonly administered to acute COVID-19 patients (the Janus kinase inhibitors, baricitinib, ruxolitinib and tofacitinib) were able to restore normal cell viability, proliferation and neurogenesis by targeting the effects of IL12 and IL13.

Overall, our results show that serum from COVID-19 patients with delirium can negatively affect hippocampal-dependent neurogenic processes, and that this effect is mediated by IL6-induced production of the downstream inflammatory cytokines IL12 and IL13, which are ultimately responsible for the detrimental cellular outcomes.

Source: Borsini, A., Merrick, B., Edgeworth, J. et al. Neurogenesis is disrupted in human hippocampal progenitor cells upon exposure to serum samples from hospitalized COVID-19 patients with neurological symptoms. Mol Psychiatry (2022). https://doi.org/10.1038/s41380-022-01741-1  (Full text)

Molecular Mimicry between SARS-CoV-2 and Human Endocrinocytes: A Prerequisite of Post-COVID-19 Endocrine Autoimmunity?

Abstract:

Molecular mimicry between human and microbial/viral/parasite peptides is common and has long been associated with the etiology of autoimmune disorders provoked by exogenous pathogens. A growing body of evidence accumulated in recent years suggests a strong correlation between SARS-CoV-2 infection and autoimmunity. The article analyzes the immunogenic potential of the peptides shared between the SARS-CoV-2 spike glycoprotein (S-protein) and antigens of human endocrinocytes involved in most common autoimmune endocrinopathies.

A total of 14 pentapeptides shared by the SARS-CoV-2 S-protein, thyroid, pituitary, adrenal cortex autoantigens and beta-cells of the islets of Langerhans were identified, all of them belong to the immunoreactive epitopes of SARS-CoV-2. The discussion of the findings relates the results to the clinical correlates of COVID-19-associated autoimmune endocrinopathies. The most common of these illnesses is an autoimmune thyroid disease, so the majority of shared pentapeptides belong to the marker autoantigens of this disease.

The most important in pathogenesis of severe COVID-19, according to the authors, may be autoimmunity against adrenals because their adequate response prevents excessive systemic action of the inflammatory mediators causing cytokine storm and hemodynamic shock. A critique of the antigenic mimicry concept is given with an assertion that peptide sharing is not a guarantee but only a prerequisite for provoking autoimmunity based on the molecular mimicry. The latter event occurs in carriers of certain HLA haplotypes and when a shared peptide is only used in antigen processing.

Source: Churilov LP, Normatov MG, Utekhin VJ. Molecular Mimicry between SARS-CoV-2 and Human Endocrinocytes: A Prerequisite of Post-COVID-19 Endocrine Autoimmunity? Pathophysiology. 2022 Aug 25;29(3):486-494. doi: 10.3390/pathophysiology29030039. PMID: 36136066; PMCID: PMC9504401. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9504401/ (Full text)

Circulating anti-nuclear autoantibodies in COVID-19 survivors predict long-COVID symptoms

Abstract:

Background: Autoimmunity has been reported in patients with severe COVID-19. We investigated whether antinuclear/extractable-nuclear antibodies (ANAs) were present up to a year after infection, and if they were associated with the development of clinically relevant Post-Acute Sequalae of COVID-19 (PASC) symptoms.

Methods: A rapid assessment line immunoassay was used to measure circulating levels of ANA/ENAs in 106 convalescent COVID-19 patients with varying acute phase severities at 3, 6, and 12 months post-recovery. Patient-reported fatigue, cough, and dyspnea were recorded at each timepoint. Multivariable logistic regression model and receiver-operating curves (ROC) were used to test the association of autoantibodies with patient-reported outcomes and pro-inflammatory cytokines.

Results: Compared to age- and sex-matched healthy controls (n=22) and those who had other respiratory infections (n=34), patients with COVID-19 had higher detectable ANAs at 3 months post-recovery (p<0.001). The mean number of ANA autoreactivities per individual decreased from 3 to 12 months (3.99 to 1.55) with persistent positive titers associated with fatigue, dyspnea, and cough severity. Antibodies to U1-snRNP and anti-SS-B/La were both positively associated with persistent symptoms of fatigue (p<0.028, AUC=0.86) and dyspnea (p<0.003, AUC=0.81). Pro-inflammatory cytokines such as tumour necrosis factor alpha (TNFα) and C-reactive protein predicted the elevated ANAs at 12 months. TNFα, D-dimer, and IL-1β had the strongest association with symptoms at 12 months. Regression analysis showed TNFα predicted fatigue (β=4.65, p=0.004) and general symptomaticity (β=2.40, p=0.03) at 12 months.

Interpretation: Persistently positive ANAs at 12 months post-COVID are associated with persisting symptoms and inflammation (TNFα) in a subset of COVID-19 survivors. This finding indicates the need for further investigation into the role of autoimmunity in PASC.

Source: Son K, Jamil R, Chowdhury A, Mukherjee M, Venegas C, Miyasaki K, Zhang K, Patel Z, Salter B, Yuen ACY, Lau KS, Cowbrough B, Radford K, Huang C, Kjarsgaard M, Dvorkin-Gheva A, Smith J, Li QZ, Waserman S, Ryerson CJ, Nair P, Ho T, Balakrishnan N, Nazy I, Bowdish DM, Svenningsen S, Carlsten C, Mukherjee M. Circulating anti-nuclear autoantibodies in COVID-19 survivors predict long-COVID symptoms. Eur Respir J. 2022 Sep 22:2200970. doi: 10.1183/13993003.00970-2022. Epub ahead of print. PMID: 36137590. https://pubmed.ncbi.nlm.nih.gov/36137590/

Dysregulated autoantibodies targeting vaso- and immunoregulatory receptors in Post COVID Syndrome correlate with symptom severity

Most patients with Post COVID Syndrome (PCS) present with a plethora of symptoms without clear evidence of organ dysfunction. A subset of them fulfills diagnostic criteria of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Symptom severity of ME/CFS correlates with natural regulatory autoantibody (AAB) levels targeting several G-protein coupled receptors (GPCR).

In this exploratory study, we analyzed serum AAB levels against vaso- and immunoregulatory receptors, mostly GPCRs, in 80 PCS patients following mild-to-moderate COVID-19, with 40 of them fulfilling diagnostic criteria of ME/CFS. Healthy seronegative (n=38) and asymptomatic post COVID-19 controls (n=40) were also included in the study as control groups.

We found lower levels for various AABs in PCS compared to at least one control group, accompanied by alterations in the correlations among AABs. Classification using random forest indicated AABs targeting ADRB2, STAB1, and ADRA2A as the strongest classifiers (AABs stratifying patients according to disease outcomes) of post COVID-19 outcomes. Several AABs correlated with symptom severity in PCS groups. Remarkably, severity of fatigue and vasomotor symptoms were associated with ADRB2 AAB levels in PCS/ME/CFS patients.

Our study identified dysregulation of AAB against various receptors involved in the autonomous nervous system (ANS), vaso-, and immunoregulation and their correlation with symptom severity, pointing to their role in the pathogenesis of PCS.

Source: Franziska Sotzny, Igor Salerno Filgueiras, Claudia Kedor, Helma Freitag, Kirsten Wittke, Sandra Bauer, Nuno Sepúlveda, Dennyson Leandro Mathias da Fonseca, Gabriela Crispim Baiocchi, Alexandre H. C. Marques, Myungjin Kim, Tanja Lange, Desirée Rodrigues Plaça, Finn Luebber, Frieder M. Paulus, Roberta De Vito, Igor Jurisica, Kai Schulze-Forster, Friedemann Paul, Judith Bellmann-Strobl, Rebekka Rust, Uta Hoppmann, Yehuda Shoenfeld, Gabriela Riemekasten, Harald Heidecke, Otavio Cabral-Marques, Carmen Scheibenbogen. Dysregulated autoantibodies targeting vaso- and immunoregulatory receptors in Post COVID Syndrome correlate with symptom severity. Front. Immunol., 27 September 2022
Sec. Autoimmune and Autoinflammatory Disorders https://doi.org/10.3389/fimmu.2022.981532 (Full text)

Impact of cross-coronavirus immunity in post-acute sequelae of COVID-19

Abstract:

Beyond the unpredictable acute illness caused by SARS-CoV-2, one-fifth of infections unpredictably result in long-term persistence of symptoms despite the apparent clearance of infection. Insights into the mechanisms that underlie post-acute sequelae of COVID-19 (PASC) will be critical for the prevention and clinical management of long-term complications of COVID-19. Several hypotheses have been proposed that may account for the development of PASC, including persistence of virus or the dysregulation of immunity. Among the immunological changes noted in PASC, alterations in humoral immunity have been observed in some patient subsets.

To begin to determine whether SARS-CoV-2 or other pathogen specific humoral immune responses evolve uniquely in PASC, we performed comprehensive antibody profiling against SARS-CoV-2 and a panel of endemic pathogens or routine vaccine antigens using Systems Serology in a cohort of patients with pre-existing rheumatic disease who either developed or did not develop PASC.

A distinct humoral immune response was observed in individuals with PASC. Specifically, individuals with PASC harbored less inflamed and weaker Fcγ receptor binding anti-SARS-CoV-2 antibodies and a significantly expanded and more inflamed antibody response against endemic Coronavirus OC43. Individuals with PASC, further, generated more avid IgM responses and developed an expanded inflammatory OC43 S2-specific Fc-receptor binding response, linked to cross reactivity across SARS-CoV-2 and common coronaviruses. These findings implicate previous common Coronavirus imprinting as a marker for the development of PASC.

Source: Jonathan D. Herman, Caroline Atyeo, Yonatan Zur, Claire E. Cook, Naomi J. Patel, Kathleen M. Vanni, Emily N. Kowalski, Grace Qian, Nancy A. Shadick, Douglas Laffenburger, Zachary S. Wallace, Jeffrey A. Sparks, Galit Alter. Impact of cross-coronavirus immunity in post-acute sequelae of COVID-19. medRxiv 2022.09.25.22280335; doi: https://doi.org/10.1101/2022.09.25.22280335 https://www.medrxiv.org/content/10.1101/2022.09.25.22280335v1.full-text (Full text)

Inflammation and autoreactivity define a discrete subset of patients with post-acute sequelae of COVID-19, or long-COVID

Abstract:

While significant attention has been paid to the immunologic determinants of disease states associated with COVID-19, their contributions to post-acute sequelae of COVID-19 (PASC) remain less clear. Due to the wide array of PASC presentations, it is critical to understand if specific features of the disease are associated with discrete immune processes, and whether those processes may be therapeutically targeted. To this end, we performed wide immunologic and serological characterization of patients in the early recovery phase of COVID-19 across a breadth of symptomatic presentations.

Using high-parameter proteomics screening and applied machine learning (ML), we identify clear signatures of immunologic activity between PASC patients and uncomplicated recovery, dominated by inflammatory cytokine signaling, neutrophil activity, and markers of cell death. Consistent with disease complexity, heterogeneity in plasma profiling reveals distinct PASC subsets with striking divergence in these ongoing inflammatory processes, here termed plasma quiescent (plaq) and inflammatory (infl) PASC.

In addition to elevated inflammatory blood proteomics, inflPASC patients display positive clinical tests of acute inflammation including C-reactive protein and fibrinogen, increased B cell activity with extrafollicular involvement coupled with elevated targeting of viral nucleocapsid protein and clinical autoreactivity. Further, the unique plasma signatures of PASC patients allowed for the creation of refined models with high sensitivity and specificity for the positive identification of inflPASC with a streamlined assessment of 12 blood markers. Additionally, refined ML modeling highlights the unexpected significance of several markers of potential diagnostic or therapeutic use for PASC in general, including the peptide hormone, epiregulin.

In all, this work identifies clear biological signatures of PASC with potential diagnostic and therapeutic potential and establishes clear disease subtypes that are both easily identifiable and highly relevant to ongoing efforts in both therapeutic targeting and epidemiological investigation of this highly complex disease.

Source: Matthew Woodruff, Kevin S Bonham, Fabliha A Anam, Tiffany Walker, Yusho Ishii, Candice Y Kaminski, Martin Runnstrom, Alexander Truong, Adviteeya Dixit, Jenny Han, Richard Ramonell, Natalie S. Haddad, Mark Rudoloph, Arezou Khosroshahi, Scott A Jenks, F. Eun-Hyung Lee, Ignacio Sanz. Inflammation and autoreactivity define a discrete subset of patients with post-acute sequelae of COVID-19, or long-COVID. medRxiv 2021.09.21.21263845; doi: https://doi.org/10.1101/2021.09.21.21263845.  (Full text available as PDF file)

COVID-19 immunopathology: From acute diseases to chronic sequelae

Abstract:

The clinical manifestation of coronavirus disease 2019 (COVID-19) mainly targets the lung as a primary affected organ, which is also a critical site of immune cell activation by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, recent reports also suggest the involvement of extrapulmonary tissues in COVID-19 pathology.

The interplay of both innate and adaptive immune responses is key to COVID-19 management. As a result, a robust innate immune response provides the first line of defense, concomitantly, adaptive immunity neutralizes the infection and builds memory for long-term protection. However, dysregulated immunity, both innate and adaptive, can skew towards immunopathology both in acute and chronic cases.

Here we have summarized some of the recent findings that provide critical insight into the immunopathology caused by SARS-CoV-2, in acute and post-acute cases. Finally, we further discuss some of the immunomodulatory drugs in preclinical and clinical trials for dampening the immunopathology caused by COVID-19.

Source: Arish M, Qian W, Narasimhan H, Sun J. COVID-19 immunopathology: From acute diseases to chronic sequelae. J Med Virol. 2022 Sep 3. doi: 10.1002/jmv.28122. Epub ahead of print. PMID: 36056655. https://onlinelibrary.wiley.com/doi/10.1002/jmv.28122 (Full text)

Low Prevalence of Interferon-α Autoantibodies in People Experiencing Long COVID Symptoms

Abstract:

Interferon (IFN)-specific autoantibodies have been implicated in severe COVID-19 and have been proposed as a potential driver of the persistent symptoms characterizing Long COVID, a type of post-acute sequelae of SARS-CoV-2 infection (PASC). We report than only two of 215 SARS-CoV-2 convalescent participants tested over 394 timepoints, including 121 people experiencing Long COVID symptoms, had detectable IFN-α2 antibodies. Both had been hospitalized during the acute phase of the infection. These data suggest that persistent anti-IFN antibodies, although a potential driver of severe COVID-19, are unlikely to contribute to Long COVID symptoms in the post-acute phase of the infection.

Source: Peluso MJ, Mitchell A, Wang CY, Takahashi S, Hoh R, Tai V, Durstenfeld MS, Hsue PY, Kelly JD, Martin JN, Wilson MR, Greenhouse B, Deeks SG, DeRisi JL, Henrich TJ. Low Prevalence of Interferon-α Autoantibodies in People Experiencing Long COVID Symptoms. J Infect Dis. 2022 Sep 12:jiac372. doi: 10.1093/infdis/jiac372. Epub ahead of print. PMID: 36089700.  https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiac372/6696027 (Full text available as PDF file)

The majority of severe COVID-19 patients develop anti-cardiac autoantibodies

Abstract:

Severe cases of COVID-19 are characterized by an inflammatory burst, which is accompanied by multiorgan failure. The elderly population has higher risk for severe or fatal outcome for COVID-19. Inflammatory mediators facilitate the immune system to combat viral infection by producing antibodies against viral antigens. Several studies reported that the pro-inflammatory state and tissue damage in COVID-19 also promotes autoimmunity by autoantibody generation. We hypothesized that a subset of these autoantibodies targets cardiac antigens.

Here we aimed to detect anti-cardiac autoantibodies in severe COVID-19 patients during hospitalization. For this purpose, 104 COVID-19 patients were recruited, while 40 heart failure patients with dilated cardiomyopathy and 20 patients with severe aortic stenosis served as controls. Patients were tested for anti-cardiac autoantibodies, using human heart homogenate as a bait. Follow-up samples were available in 29 COVID-19 patients. Anti-cardiac autoantibodies were detected in 68% (71 out of 104) of severe COVID-19 patients.

Overall, 39% of COVID-19 patients had anti-cardiac IgG autoantibodies, while 51% had anti-cardiac autoantibodies of IgM isotype. Both IgG and IgM anti-cardiac autoantibodies were observed in 22% of cases, and multiple cardiac antigens were targeted in 38% of COVID-19 patients. These anti-cardiac autoantibodies targeted a diverse set of myocardial proteins, without apparent selectivity. As controls, heart failure patients (with dilated cardiomyopathy) had similar occurrence of IgG (45%, p = 0.57) autoantibodies, while significantly lower occurrence of IgM autoantibodies (30%, p = 0.03). Patients with advanced aortic stenosis had significantly lower number of both IgG (11%, p = 0.03) and IgM (10%, p < 0.01) type anti-cardiac autoantibodies than that in COVID-19 patients. Furthermore, we detected changes in the anti-cardiac autoantibody profile in 7 COVID-19 patients during hospital treatment.

Surprisingly, the presence of these anti-cardiac autoantibodies did not affect the clinical outcome and the prevalence of the autoantibodies did not differ between the elderly (over 65 years) and the patients younger than 65 years of age. Our results demonstrate that the majority of hospitalized COVID-19 patients produce novel anti-cardiac IgM autoantibodies. COVID-19 also reactivates resident IgG autoantibodies. These autoantibodies may promote autoimmune reactions, which can complicate post-COVID recuperation, contributing to post-acute sequelae of COVID-19 (long COVID).

Source: Fagyas M, Nagy B Jr, Ráduly AP, Mányiné IS, Mártha L, Erdősi G, Sipka S Jr, Enyedi E, Szabó AÁ, Pólik Z, Kappelmayer J, Papp Z, Borbély A, Szabó T, Balla J, Balla G, Bai P, Bácsi A, Tóth A. The majority of severe COVID-19 patients develop anti-cardiac autoantibodies. Geroscience. 2022 Sep 16:1–14. doi: 10.1007/s11357-022-00649-6. Epub ahead of print. PMID: 36112333; PMCID: PMC9483490. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9483490/ (Full text)