Long COVID manifests with T cell dysregulation, inflammation, and an uncoordinated adaptive immune response to SARS-CoV-2

Abstract:

Long COVID (LC), a type of post-acute sequelae of SARS-CoV-2 infection (PASC), occurs after at least 10% of SARS-CoV-2 infections, yet its etiology remains poorly understood. Here, we used multiple “omics” assays (CyTOF, RNAseq, Olink) and serology to deeply characterize both global and SARS-CoV-2-specific immunity from blood of individuals with clear LC and non-LC clinical trajectories, 8 months following infection and prior to receipt of any SARS-CoV-2 vaccine. Our analysis focused on deep phenotyping of T cells, which play important roles in immunity against SARS-CoV-2 yet may also contribute to COVID-19 pathogenesis.

Our findings demonstrate that individuals with LC exhibit systemic inflammation and immune dysregulation. This is evidenced by global differences in T cell subset distribution in ways that imply ongoing immune responses, as well as by sex-specific perturbations in cytolytic subsets. Individuals with LC harbored increased frequencies of CD4+ T cells poised to migrate to inflamed tissues, and exhausted SARS-CoV-2-specific CD8+ T cells. They also harbored significantly higher levels of SARS-CoV-2 antibodies, and in contrast to non-LC individuals, exhibited a mis-coordination between their SARS-CoV-2-specific T and B cell responses.

Collectively, our data suggest that proper crosstalk between the humoral and cellular arms of adaptive immunity has broken down in LC, and that this, perhaps in the context of persistent virus, leads to the immune dysregulation, inflammation, and clinical symptoms associated with this debilitating condition.

Source: Kailin Yin, Michael J. Peluso, Reuben Thomas, Min Gyoung Shin, Jason Neidleman, Xiaoyu Luo, Rebecca Hoh, Khamal Anglin, Beatrice Huang, Urania Argueta, Monica Lopez, Daisy Valdivieso, Kofi Asare, Rania Ibrahim, Ludger Ständker, Scott Lu, Sarah A. Goldberg, Sulggi A. Lee, Kara L. Lynch, J. Daniel Kelly, Jeffrey N. Martin, Jan Münch, Steven G. Deeks, Timothy J. Henrich, Nadia R. Roan. Long COVID manifests with T cell dysregulation, inflammation, and an uncoordinated adaptive immune response to SARS-CoV-2. bioRxiv 2023.02.09.527892; doi: https://doi.org/10.1101/2023.02.09.527892 https://www.biorxiv.org/content/10.1101/2023.02.09.527892v1.full (Full text)

Vascular Function, Systemic Inflammation, and Coagulation Activation 18 Months after COVID-19 Infection: An Observational Cohort Study

Abstract:

Introduction: Among its effect on virtually all other organs, COVID-19 affects the cardiovascular system, potentially jeopardizing the cardiovascular health of millions. Previous research has shown no indication of macrovascular dysfunction as reflected by carotid artery reactivity, but has shown sustained microvascular dysfunction, systemic inflammation, and coagulation activation at 3 months after acute COVID-19. The long-term effects of COVID-19 on vascular function remain unknown.
Materials and Methods: This cohort study involved 167 patients who participated in the COVAS trial. At 3 months and 18 months after acute COVID-19, macrovascular dysfunction was evaluated by measuring the carotid artery diameter in response to cold pressor testing. Additionally, plasma endothelin-1, von Willebrand factor, Interleukin(IL)-1ra, IL-6, IL-18, and coagulation factor complexes were measured using ELISA techniques.
Results: The prevalence of macrovascular dysfunction did not differ between 3 months (14.5%) and 18 months (11.7%) after COVID-19 infection (p = 0.585). However, there was a significant decrease in absolute carotid artery diameter change, 3.5% ± 4.7 vs. 2.7% ± 2.5, p—0.001, respectively. Additionally, levels of vWF:Ag were persistently high in 80% of COVID-19 survivors, reflecting endothelial cell damage and possibly attenuated endothelial function. Furthermore, while levels of the inflammatory cytokines interleukin(IL)-1RA and IL-18 were normalized and evidence of contact pathway activation was no longer present, the concentrations of IL-6 and thrombin:antithrombin complexes were further increased at 18 months versus 3 months (2.5 pg/mL ± 2.6 vs. 4.0 pg/mL ± 4.6, p = 0.006 and 4.9 μg/L ± 4.4 vs. 18.2 μg/L ± 11.4, p < 0.001, respectively).
Discussion: This study shows that 18 months after COVID-19 infection, the incidence of macrovascular dysfunction as defined by a constrictive response during carotid artery reactivity testing is not increased. Nonetheless, plasma biomarkers indicate sustained endothelial cell activation (vWF), systemic inflammation (IL-6), and extrinsic/common pathway coagulation activation (FVII:AT, TAT) 18 months after COVID-19 infection.
Source: Willems LH, Jacobs LMC, Groh LA, ten Cate H, Spronk HMH, Wilson-Storey B, Hannink G, van Kuijk SMJ, Ghossein-Doha C, Nagy M, Thijssen DHJ, van Petersen AS, Warlé MC. Vascular Function, Systemic Inflammation, and Coagulation Activation 18 Months after COVID-19 Infection: An Observational Cohort Study. Journal of Clinical Medicine. 2023; 12(4):1413. https://doi.org/10.3390/jcm12041413 https://www.mdpi.com/2077-0383/12/4/1413 (Full text)

Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation?

Abstract:

As inflammation in the brain contributes to several neurological and psychiatric diseases, the cause of neuroinflammation is being widely studied. The causes of neuroinflammation can be roughly divided into the following domains: viral infection, autoimmune disease, inflammation from peripheral organs, mental stress, metabolic disorders, and lifestyle. In particular, the effects of neuroinflammation caused by inflammation of peripheral organs have yet unclear mechanisms.

Many diseases, such as gastrointestinal inflammation, chronic obstructive pulmonary disease, rheumatoid arthritis, dermatitis, chronic fatigue syndrome, or myalgic encephalomyelitis (CFS/ME), trigger neuroinflammation through several pathways. The mechanisms of action for peripheral inflammation-induced neuroinflammation include disruption of the blood-brain barrier, activation of glial cells associated with systemic immune activation, and effects on autonomic nerves via the organ-brain axis. In this review, we consider previous studies on the relationship between systemic inflammation and neuroinflammation, focusing on the brain regions susceptible to inflammation.

Source: Sun Y, Koyama Y, Shimada S. Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation? Front Aging Neurosci. 2022 Jun 16;14:903455. doi: 10.3389/fnagi.2022.903455. PMID: 35783147; PMCID: PMC9244793. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9244793/ (Full text)

Long COVID: systemic inflammation and obesity as therapeutic targets

Management of the post-COVID-19 condition—often referred to as long COVID—is a challenge for health-care professionals because of the heterogeneity and complexity of its clinical manifestations and the probable need for multidisciplinary management approaches. Identification and understanding of modifiable determinants associated with manifestations of long COVID would help in the adaptation of treatment pathways for particular phenotypes. In The Lancet Respiratory Medicine, the PHOSP-COVID Collaborative Group report the latest results from the UK-based, multicentre, prospective Post-hospitalisation COVID-19 (PHOSP-COVID) study, in which the investigators identified systemic inflammation and obesity as factors that might be associated with long COVID, representing potentially treatable traits in people with more severe post-COVID-19 symptoms.

In the current report, the PHOSP-COVID Collaborative Group found increased levels of several biomarkers related to systemic inflammation and lung damage in individuals with more severe physical and mental health impairments 1 year after hospital discharge. The presence of increased levels of systemic inflammatory biomarkers (eg, cytokines) in individuals with severe acute COVID-19 has been reported previously. Moreover, the use of anti-inflammatory agents such as corticosteroids or interleukin-6 (IL-6)-blocking agents has been found to be associated with positive outcomes in patients hospitalised with acute COVID-19.

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Source: Florencio LL, Fernández-de-Las-Peñas C. Long COVID: systemic inflammation and obesity as therapeutic targets. Lancet Respir Med. 2022 Apr 22:S2213-2600(22)00159-X. doi: 10.1016/S2213-2600(22)00159-X. Epub ahead of print. PMID: 35472305; PMCID: PMC9034853. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9034853/ (Full text)