Tag: long covid immunology

Distinguishing features of Long COVID identified through immune profiling

Abstract:

SARS-CoV-2 infection can result in the development of a constellation of persistent sequelae following acute disease called post-acute sequelae of COVID-19 (PASC) or Long COVID. Individuals diagnosed with Long COVID frequently report unremitting fatigue, post-exertional malaise, and a variety of cognitive and autonomic dysfunctions; however, the basic biological mechanisms responsible for these debilitating symptoms are unclear. Here, 215 individuals were included in an exploratory, cross-sectional study to perform multi-dimensional immune phenotyping in conjunction with machine learning methods to identify key immunological features distinguishing Long COVID.

Marked differences were noted in specific circulating myeloid and lymphocyte populations relative to matched control groups, as well as evidence of elevated humoral responses directed against SARS-CoV-2 among participants with Long COVID. Further, unexpected increases were observed in antibody responses directed against non-SARS-CoV-2 viral pathogens, particularly Epstein-Barr virus.

Analysis of circulating immune mediators and various hormones also revealed pronounced differences, with levels of cortisol being uniformly lower among participants with Long COVID relative to matched control groups. Integration of immune phenotyping data into unbiased machine learning models identified significant distinguishing features critical in accurate classification of Long COVID, with decreased levels of cortisol being the most significant individual predictor. These findings will help guide additional studies into the pathobiology of Long COVID and may aid in the future development of objective biomarkers for Long COVID.

Source: Jon Klein, Jamie Wood, Jillian Jaycox, Peiwen Lu, Rahul M. Dhodapkar, Jeffrey R. Gehlhausen, Alexandra Tabachnikova, Laura Tabacof, Amyn A. Malik, Kathy Kamath, Kerrie Greene, Valter Silva Monteiro, Mario Pena-Hernandez, Tianyang Mao, Bornali Bhattacharjee, Takehiro Takahashi, Carolina Lucas, Julio Silva, Dayna Mccarthy, Erica Breyman, Jenna Tosto-Mancuso, Yile Dai, Emily Perotti, Koray Akduman, Tiffany Tzeng, Lan Xu, Inci Yildirim, Harlan M. Krumholz, John Shon, Ruslan Medzhitov, Saad B. Omer, David van Dijk, Aaron M. Ring, David Putrino, Akiko Iwasaki. Distinguishing features of Long COVID identified through immune profiling. medRxiv 2022.08.09.22278592; doi: https://doi.org/10.1101/2022.08.09.22278592

Cytokine Profiles Associated With Acute COVID-19 and Long COVID-19 Syndrome

Abstract:

The duration and severity of COVID-19 are related to age, comorbidities, and cytokine synthesis. This study evaluated the impact of these factors on patients with clinical presentations of COVID-19 in a Brazilian cohort.

A total of 317 patients diagnosed with COVID-19 were included; cases were distributed according to clinical status as severe (n=91), moderate (n=56) and mild (n=170). Of these patients, 92 had acute COVID-19 at sample collection, 90 had already recovered from COVID-19 without sequelae, and 135 had sequelae (long COVID syndrome).

In the acute COVID-19 group, patients with the severe form had higher IL-6 levels (p=0.0260). In the post-COVID-19 group, there was no significant difference in cytokine levels between groups with different clinical conditions. In the acute COVID-19 group, younger patients had higher levels of TNF-α, and patients without comorbidities had higher levels of TNF-α, IL-4 and IL-2 (p<0.05). In contrast, patients over age 60 with comorbidities had higher levels of IL-6. In the post-COVID-19 group, subjects with long COVID-19 had higher levels of IL-17 and IL-2 (p<0.05), and subjects without sequelae had higher levels of IL-10, IL-6 and IL- 4 (p<0.05).

Our results suggest that advanced age, comorbidities and elevated serum IL-6 levels are associated with severe COVID-19 and are good markers to differentiate severe from mild cases. Furthermore, high serum levels of IL-17 and IL-2 and low levels of IL-4 and IL-10 appear to constitute a cytokine profile of long COVID-19, and these markers are potential targets for COVID-19 treatment and prevention strategies.

Source: Queiroz MAF, Neves PFMD, Lima SS, Lopes JDC, Torres MKDS, Vallinoto IMVC, Bichara CDA, Dos Santos EF, de Brito MTFM, da Silva ALS, Leite MM, da Costa FP, Viana MNDSA, Rodrigues FBB, de Sarges KML, Cantanhede MHD, da Silva R, Bichara CNC, van den Berg AVS, Veríssimo AOL, Carvalho MDS, Henriques DF, Dos Santos CP, Nunes JAL, Costa IB, Viana GMR, Carneiro FRO, Palacios VRDCM, Quaresma JAS, Brasil-Costa I, Dos Santos EJM, Falcão LFM, Vallinoto ACR. Cytokine Profiles Associated With Acute COVID-19 and Long COVID-19 Syndrome. Front Cell Infect Microbiol. 2022 Jun 30;12:922422. doi: 10.3389/fcimb.2022.922422. PMID: 35846757; PMCID: PMC9279918. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9279918/ (Full text)

Long-COVID in immunocompromised children

Abstract:

Coronavirus disease 2019 (COVID-19) can lead to an illness characterized by persistent symptoms which affect various organs and systems, known as long-COVID. This study aimed to assess the prevalence and clinical characteristics of long-COVID in children with immunodeficiency, in comparison to those without. A self-constructed questionnaire was created, which included questions regarding the child’s general health, the course of their COVID-19, their symptoms of long-COVID and its impact on their daily functioning, the diagnosis of multisystem inflammatory syndrome (MIS-C), and vaccination status. The questionnaire was completed by parents of 147 children – 70 children with a diagnosis of immunodeficiency (47.6%) and 77 who were immunocompetent (52.4%).

Immunocompetent children were more significantly affected by long-COVID than those immunocompromised. Its prevalence in the first 12-week post-infection was 60.0% and 35.7% in these groups, respectively. Beyond this period, these percentages had dropped to 34.6% and 11.43%, respectively. Children who were immunocompetent reported more often symptoms of fatigue, reduced exercise tolerance, and difficulty concentrating. Meanwhile, there was a slight increase in complaints of gastrointestinal symptoms in immunocompromised patients. The risk of developing long-COVID increased with age and COVID-19 severity in both groups. Furthermore, the daily activities of immunocompetent children were limited more frequently (41.8%) than for those who were immunocompromised (25%).

Conclusions: Although immunocompromised children experienced long-COVID, its prevalence and impact on daily functioning were significantly lower than among immunocompetent children. However, as the pathomechanisms of long-COVID are not yet fully understood, it is not currently possible to fully explain these findings.

What is known: • Long COVID is characterized by persistent symptoms following COVID-19, which can affect various tissues and organs, as well as mental health. • Due to the similar course of COVID-19 – mainly mild or asymptomatic – among children with and without immunodeficiency, the question arises, over whether the prevalence and severity of long-COVID is also similar in both groups.

What is new: • Immunocompromised children also suffer from long-COVID, but the prevalence is significantly lower than in the immunocompetent group of children. • The potential causes of less frequent and milder long-COVID in this group may be the milder course of COVID-19 and the state of reduced immunity protecting against neuroinflammation.

Source: Kuczborska K, Buda P, Książyk J. Long-COVID in immunocompromised children. Eur J Pediatr. 2022 Jul 14:1–9. doi: 10.1007/s00431-022-04561-1. Epub ahead of print. PMID: 35834042; PMCID: PMC9281224.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9281224/ (Full text)

Evidence of previous SARS-CoV-2 infection in seronegative patients with long COVID

Abstract:

Background: There is currently no consensus on the diagnosis, definition, symptoms, or duration of COVID-19 illness. The diagnostic complexity of Long COVID is compounded in many patients who were or might have been infected with SARS-CoV-2 but not tested during the acute illness and/or are SARS-CoV-2 antibody negative.

Methods: Given the diagnostic conundrum of Long COVID, we set out to investigate SARS-CoV-2-specific T cell responses in patients with confirmed SARS-CoV-2 infection and/or Long COVID from a cohort of mostly non-hospitalised patients.

Findings: We discovered that IL-2 release (but not IFN-γ release) from T cells in response to SARS-CoV-2 peptides is both sensitive (75% +/-13%) and specific (88%+/-7%) for previous SARS-CoV-2 infection >6 months after a positive PCR test. We identified that 42-53% of patients with Long COVID, but without detectable SARS-CoV-2 antibodies, nonetheless have detectable SARS-CoV-2 specific T cell responses.

Interpretation: Our study reveals evidence (detectable T cell mediated IL-2 release) of previous SARS-CoV-2 infection in seronegative patients with Long COVID.

Funding: This work was funded by the Addenbrooke’s Charitable Trust (900276 to NS), NIHR award (G112259 to NS) and supported by the NIHR Cambridge Biomedical Research Centre. NJM is supported by the MRC (TSF MR/T032413/1) and NHSBT (WPA15-02). PJL is supported by the Wellcome Trust (PRF 210688/Z/18/Z, 084957/Z/08/Z), a Medical Research Council research grant MR/V011561/1 and the United Kingdom Research and a Innovation COVID Immunology Consortium grant (MR/V028448/1).

Source: Krishna BA, Lim EY, Mactavous L; NIHR BioResource Team, Lyons PA, Doffinger R, Bradley JR, Smith KGC, Sinclair J, Matheson NJ, Lehner PJ, Wills MR, Sithole N. Evidence of previous SARS-CoV-2 infection in seronegative patients with long COVID. EBioMedicine. 2022 Jul;81:104129. doi: 10.1016/j.ebiom.2022.104129. Epub 2022 Jun 27. PMID: 35772216; PMCID: PMC9235296. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9235296/ (Full text)

Multi-omics provide evidence for an anti-inflammatory immune signature and metabolic alterations in patients with Long COVID Syndrome; an exploratory study

Abstract:

Despite the increasing prevalence of patients with Long Covid Syndrome (LCS), to date the pathophysiology of the disease is still unclear, and therefore diagnosis and therapy are a complex effort without any standardization. To address these issues, we performed a broad exploratory screening study applying state-of-the-art post-genomic profiling methods to blood plasma derived from three groups: 1) healthy individuals vaccinated against SARS-CoV-2 without exposure to the full virus, 2) asymptomatic fully recovered patients at least three months after SARS-CoV-2 infection, 3) symptomatic patients at least 3 months after a SARS-CoV-2 infection, here designated as Long Covid Syndrome (LCS) patients.

Multiplex cytokine profiling indicated slightly elevated cytokine levels in recovered individuals in contrast to LCS patients, who displayed lowest levels of cytokines. Label-free proteome profiling corroborated an anti-inflammatory status in LCS characterized by low acute phase protein levels and a uniform down-regulation of macrophage-derived secreted proteins, a pattern also characteristic for chronic fatigue syndrome (CFS).

Along those lines, eicosanoid and docosanoid analysis revealed high levels of omega-3 fatty acids and a prevalence of anti-inflammatory oxylipins in LCS patients compared to the other study groups. Targeted metabolic profiling indicated low amino acid and triglyceride levels and deregulated acylcarnithines, characteristic for CFS and indicating mitochondrial stress in LCS patients. The anti-inflammatory osmolytes taurine and hypaphorine were significantly up-regulated in LCS patients.

In summary, here we present evidence for a specific anti-inflammatory and highly characteristic metabolic signature in LCS which could serve for future diagnostic purposes and help to establish rational therapeutic interventions in these patients.

Source: Johannes J Kovarik, Andrea Bileck, Gerhard Hagn, Samuel M Meier Menches, Tobias Frey, Anna Kaempf, Marlene Hollenstein, Tarik Shoumariyeh, Lukas Skos, Birgit Reiter, Marlene C Gerner, Andreas Spannbauer, Ena Hasimbegovic, Doreen Schmidl, Gerhard Garhoefer, Mariann Gyoengyoesi, Klaus G Schmetterer, Christopher Gerner. Multi-omics provide evidence for an anti-inflammatory immune signature and metabolic alterations in patients with Long COVID Syndrome; an exploratory study. medRxiv 2022.07.11.22277499; doi: https://doi.org/10.1101/2022.07.11.22277499 (Full study available as PDF file)

Is post-COVID syndrome an autoimmune disease?

Abstract:

Introduction: Post-COVID syndrome (PCS) is recognized as a new entity in the context of SARS-CoV-2 infection. Though its pathogenesis is not completely understood, persistent inflammation from acute illness and the development of autoimmunity play a critical role in its development.

Areas covered: The mechanisms involved in the emergence of PCS, their similarities with post-viral and post-care syndromes, its inclusion in the spectrum of autoimmunity and possible targets for its treatment.

Expert opinion: An autoimmune phenomenon plays a major role in most causative theories explaining PCS. There is a need for both PCS definition and classification criteria (including severity scores). Longitudinal and controlled studies are necessary to better understand this new entity, and to find what additional factors participate into its development. With the high prevalence of COVID-19 cases worldwide, together with the current evidence on latent autoimmunity in PCS, we may observe an increase of autoimmune diseases (ADs) in the coming years. Vaccination’s effect on the development of PCS and ADs will also receive attention in the future. Health and social care services need to develop a new framework to deal with PCS.

Source: Anaya JM, Herrán M, Beltrán S, Rojas M. Is post-COVID syndrome an autoimmune disease? Expert Rev Clin Immunol. 2022 Jun 14:1-14. doi: 10.1080/1744666X.2022.2085561. Epub ahead of print. PMID: 35658801. https://pubmed.ncbi.nlm.nih.gov/35658801/

SARS-CoV-2-specific T cells associate with inflammation and reduced lung function in pulmonary post-acute sequalae of SARS-CoV-2

Abstract:

As of January 2022, at least 60 million individuals are estimated to develop post-acute sequelae of SARS-CoV-2 (PASC) after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While elevated levels of SARS-CoV-2-specific T cells have been observed in non-specific PASC, little is known about their impact on pulmonary function which is compromised in the majority of these individuals. This study compares frequencies of SARS-CoV-2-specific T cells and inflammatory markers with lung function in participants with pulmonary PASC and resolved COVID-19 (RC).

Compared to RC, participants with respiratory PASC had between 6- and 105-fold higher frequencies of IFN-γ- and TNF-α-producing SARS-CoV-2-specific CD4+ and CD8+ T cells in peripheral blood, and elevated levels of plasma CRP and IL-6. Importantly, in PASC participants the frequency of TNF-α-producing SARS-CoV-2-specific CD4+ and CD8+ T cells, which exhibited the highest levels of Ki67 indicating they were activity dividing, correlated positively with plasma IL-6 and negatively with measures of lung function, including forced expiratory volume in one second (FEV1), while increased frequencies of IFN-γ-producing SARS-CoV-2-specific T cells associated with prolonged dyspnea.

Statistical analyses stratified by age, number of comorbidities and hospitalization status demonstrated that none of these factors affect differences in the frequency of SARS-CoV-2 T cells and plasma IL-6 levels measured between PASC and RC cohorts. Taken together, these findings demonstrate elevated frequencies of SARS-CoV-2-specific T cells in individuals with pulmonary PASC are associated with increased systemic inflammation and decreased lung function, suggesting that SARS-CoV-2-specific T cells contribute to lingering pulmonary symptoms. These findings also provide mechanistic insight on the pathophysiology of PASC that can inform development of potential treatments to reduce symptom burden.

Source: Katherine M. Littlefield,Renée O. Watson,Jennifer M. Schneider,Charles P. Neff,Eiko Yamada,Min Zhang,Thomas B. Campbell,Michael T. Falta,Sarah E. Jolley,Andrew P. Fontenot,Brent E. Palmer. SARS-CoV-2-specific T cells associate with inflammation and reduced lung function in pulmonary post-acute sequalae of SARS-CoV-2. PLOS Pathogens. Published: May 26, 2022 https://doi.org/10.1371/journal.ppat.1010359  (Full text)