Tag: long covid immunology

Viral persistence, reactivation, and mechanisms of long COVID

Abstract:

The COVID-19 global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has infected hundreds of millions of individuals. Following COVID-19 infection, a subset can develop a wide range of chronic symptoms affecting diverse organ systems referred to as post-acute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. A National Institutes of Health-sponsored initiative, RECOVER: Researching COVID to Enhance Recovery, has sought to understand the basis of long COVID in a large cohort. Given the range of symptoms that occur in long COVID, the mechanisms that may underlie these diverse symptoms may also be diverse.

In this review, we focus on the emerging literature supporting the role(s) that viral persistence or reactivation of viruses may play in PASC. Persistence of SARS-CoV-2 RNA or antigens is reported in some organs, yet the mechanism by which they do so and how they may be associated with pathogenic immune responses is unclear. Understanding the mechanisms of persistence of RNA, antigen or other reactivated viruses and how they may relate to specific inflammatory responses that drive symptoms of PASC may provide a rationale for treatment.

Source: Chen B, Julg B, Mohandas S, Bradfute SB; RECOVER Mechanistic Pathways Task Force. Viral persistence, reactivation, and mechanisms of long COVID. Elife. 2023 May 4;12:e86015. doi: 10.7554/eLife.86015. PMID: 37140960; PMCID: PMC10159620. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10159620/ (Full text)

Long COVID in people living with HIV

Abstract:

Purpose of review: It is now recognized that SARS-CoV-2 infection can have a long-term impact on health. This review summarizes the current state of knowledge regarding Long COVID in people living with HIV (PLWH).

Recent findings: PLWH may be at elevated risk of experiencing Long COVID. Although the mechanisms contributing to Long COVID are incompletely understood, there are several demographic and clinical factors that might make PLWH vulnerable to developing Long COVID.

Summary: PLWH should be aware that new or worsening symptoms following SARS-CoV-2 infection might represent Long COVID. HIV providers should be aware of this clinical entity and be mindful that their patients recovering from SARS-CoV-2 infection may be at higher risk.

Source: Peluso MJ, Antar AAR. Long COVID in people living with HIV. Curr Opin HIV AIDS. 2023 May 1;18(3):126-134. doi: 10.1097/COH.0000000000000789. Epub 2023 Mar 20. PMID: 37144614; PMCID: PMC10167544. https://pubmed.ncbi.nlm.nih.gov/37144614/ 

Long COVID: a review and proposed visualization of the complexity of long COVID

Abstract:

Post-Acute Sequelae of Severe Acute Respiratory Syndrome Coronavirus – 2 (SARS-CoV-2) infection, or Long COVID, is a prevailing second pandemic with nearly 100 million affected individuals globally and counting. We propose a visual description of the complexity of Long COVID and its pathogenesis that can be used by researchers, clinicians, and public health officials to guide the global effort toward an improved understanding of Long COVID and the eventual mechanism-based provision of care to afflicted patients. The proposed visualization or framework for Long COVID should be an evidence-based, dynamic, modular, and systems-level approach to the condition.

Furthermore, with further research such a framework could establish the strength of the relationships between pre-existing conditions (or risk factors), biological mechanisms, and resulting clinical phenotypes and outcomes of Long COVID. Notwithstanding the significant contribution that disparities in access to care and social determinants of health have on outcomes and disease course of long COVID, our model focuses primarily on biological mechanisms. Accordingly, the proposed visualization sets out to guide scientific, clinical, and public health efforts to better understand and abrogate the health burden imposed by long COVID.

Source: Perumal R, Shunmugam L, Naidoo K, Abdool Karim SS, Wilkins D, Garzino-Demo A, Brechot C, Parthasarathy S, Vahlne A, Nikolich JŽ. Long COVID: a review and proposed visualization of the complexity of long COVID. Front Immunol. 2023 Apr 20;14:1117464. doi: 10.3389/fimmu.2023.1117464. PMID: 37153597; PMCID: PMC10157068. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10157068/ (Full text)

Netosis -A double-edged sword in the Pathogenesis of LONG COVID

Abstract:

The emergence of COVID-19 as a global pandemic has had far-reaching effects on the health of individuals worldwide. Although there has been a decrease in the severity of the disease, there is a growing concern about the long-term impact of COVID-19 on the health of individuals, particularly cardiovascular complications, known as Long-COVID, which can significantly increase morbidity and mortality rates in people recovering from COVID-19 in the recent past.
The severity of COVID-19 has been linked to various factors, including the role of neutrophils and neutrophil extracellular traps (NET). These extracellular webs, composed of chromatin, microbicidal proteins, and oxidant enzymes, are released by neutrophils to fight infections. However, if not properly regulated, NETs can lead to thrombo-inflammatory states and microangiopathy in the body, resulting in complications such as sepsis, thrombosis, and respiratory failure.
Understanding the detailed pathophysiology and association of NETs with the prognosis of COVID-19 infection is crucial for future implications and management. The purpose of this review is to analyze the potential contribution of NETosis in the pathophysiology of COVID-19 and its subsequent complications apart from its beneficial effect. This may provide insight into potential therapeutic interventions for COVID-19 patients.
Source: Durre Aden, vagisha sharma, sufian zaheer, et al. Netosis -A double-edged sword in the Pathogenesis of LONG COVID. Authorea. April 28, 2023. https://www.authorea.com/users/570888/articles/640398-netosis-a-double-edged-sword-in-the-pathogenesis-of-long-covid (Full text available as PDF file)

Review of Neurological Manifestations of SARS-CoV-2

Abstract:

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect any part of the neuraxis. Many neurological conditions have been attributed to be caused by SARS-CoV-2, namely encephalopathy (acute necrotizing encephalopathy and encephalopathy with reversible splenial lesions), seizures, stroke, cranial nerve palsies, meningoencephalitis, acute disseminated encephalomyelitis (ADEM), transverse myelitis (long and short segment), Guillain-Barré syndrome (GBS) and its variants, polyneuritis cranialis, optic neuritis (ON), plexopathy, myasthenia gravis (MG), and myositis.

The pathophysiology differs depending on the time frame of presentation. In patients with concomitant pulmonary disease, for instance, acute neurological illness appears to be caused by endotheliopathy and cytokine storm. Autoimmunity and molecular mimicry are causative for post-coronavirus disease 2019 (COVID-19)-sequelae. It has not yet been shown that the virus can penetrate the central nervous system (CNS) directly.

This review aims to describe the disease and root pathogenic cause of the various neurological manifestations of COVID-19. We searched Pubmed/Medline and Google Scholar using the keywords “SARS-CoV-2” and “neurological illness” for articles published between January 2020 and November 2022. Then, we used the SWIFT-Review (Sciome LLC, North Carolina, United States), a text-mining workbench for systematic review, to classify the 1383 articles into MeSH hierarchical tree codes for articles on various parts of the nervous system, such as the CNS, peripheral nervous system, autonomic nervous system, neuromuscular junction, sensory system, and musculoskeletal system. Finally, we reviewed 152 articles in full text. SARS-CoV-2 RNA has been found in multiple brain areas without any histopathological changes.

Despite the absence of in vivo virions or virus-infected cells, CNS inflammation has been reported, especially in the olfactory bulb and brain stem. SARS-CoV-2 genomes and proteins have been found in affected individuals’ brain tissues, but corresponding neuropathologic changes are seldom found in these cases. Additionally, viral RNA can rarely be identified in neurological patients’ CSF post hoc SARS-CoV-2 infection.

Most patients with neurological symptoms do not have active viral replication in the nervous system and infrequently have typical clinical and laboratory characteristics of viral CNS infections. Endotheliopathy and the systemic inflammatory response to SARS-CoV-2 infection play a crucial role in developing neuro-COVID-19, with proinflammatory cytokine release mediating both pathological pathways. The systemic inflammatory mediators likely activate astrocytes and microglia across the blood-brain barrier, indirectly affecting CNS-specific immune activation and tissue injury. The management differs according to co-morbidities and the neurological disorder.

Source: P, Sehgal V, Kapila S, et al. (April 27, 2023) Review of Neurological Manifestations of SARS-CoV-2. Cureus 15(4): e38194. doi:10.7759/cureus.38194 https://www.cureus.com/articles/149269-review-of-neurological-manifestations-of-sars-cov-2#!/ (Full text)

Post-acute sequelae of COVID-19 is characterized by diminished peripheral CD8+β7 integrin+ T cells and anti-SARS-CoV-2 IgA response

Abstract:

Several millions of individuals are estimated to develop post-acute sequelae SARS-CoV-2 condition (PASC) that persists for months after infection. Here we evaluate the immune response in convalescent individuals with PASC compared to convalescent asymptomatic and uninfected participants, six months following their COVID-19 diagnosis.

Both convalescent asymptomatic and PASC cases are characterised by higher CD8+ T cell percentages, however, the proportion of blood CD8+ T cells expressing the mucosal homing receptor β7 is low in PASC patients. CD8 T cells show increased expression of PD-1, perforin and granzyme B in PASC, and the plasma levels of type I and type III (mucosal) interferons are elevated. The humoral response is characterized by higher levels of IgA against the N and S viral proteins, particularly in those individuals who had severe acute disease.  Our results also show that consistently elevated levels of IL-6, IL-8/CXCL8 and IP-10/CXCL10 during acute disease increase the risk to develop PASC.

In summary, our study indicates that PASC is defined by persisting immunological dysfunction as late as six months following SARS-CoV-2 infection, including alterations in mucosal immune parameters, redistribution of mucosal CD8+β7Integrin+ T cells and IgA, indicative of potential viral persistence and mucosal involvement in the etiopathology of PASC.

Source: Santa Cruz A, Mendes-Frias A, Azarias-da-Silva M, André S, Oliveira AI, Pires O, Mendes M, Oliveira B, Braga M, Lopes JR, Domingues R, Costa R, Silva LN, Matos AR, Ângela C, Costa P, Carvalho A, Capela C, Pedrosa J, Castro AG, Estaquier J, Silvestre R. Post-acute sequelae of COVID-19 is characterized by diminished peripheral CD8+β7 integrin+ T cells and anti-SARS-CoV-2 IgA response. Nat Commun. 2023 Mar 30;14(1):1772. doi: 10.1038/s41467-023-37368-1. PMID: 36997530; PMCID: PMC10061413. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10061413/ (Full text)

An Exercise Immune Fitness test to unravel mechanisms of post-acute sequelae of COVID-19

Abstract:

The Post-Acute Sequelae of COVID-19 (PASC) Syndrome is a debilitating syndrome with onset three months post COVID-19 infection, marked by the presence of fatigue, headache, cognitive dysfunction, post-exertional malaise, orthostatic intolerance, and dyspnea that is clinically relevant and is at least as severe as fatigue in several other clinical conditions, including cancer. The onset, progression, and symptom profile of PASC patients have considerable overlap with Myalgic-Encephalopathy/Chronic Fatigue Syndrome (ME/CFS).

In people with ME/CFS, exercise (and other types of exertion) can cause serious setbacks and deterioration in function. Post-exertional malaise (PEM) appears to be a common and a significant challenge for the majority of this patient group. Of the nearly 24 million adults in the U.S. who currently have long COVID, more than 80% are having some trouble carrying out daily activities. Mechanisms of PACS remain poorly understood.

While multi-omic information gathered at the time of acute COVID-19 onset may help predict long COVID outcomes, we here propose to test the hypothesis that additional molecular immunological information collected during standardized exercise-testing for cardio-respiratory fitness after recovery from acute COVID-19 can be used to improve the understanding of mechanisms of PASC.

Source: Deng MC. An Exercise Immune Fitness test to unravel mechanisms of post-acute sequelae of COVID-19. Expert Rev Clin Immunol. 2023 May 16. doi: 10.1080/1744666X.2023.2214364. Epub ahead of print. PMID: 37190994. https://www.tandfonline.com/doi/full/10.1080/1744666X.2023.2214364 (Full text)

Increased interleukin-6 is associated with long COVID-19: a systematic review and meta-analysis

Abstract:

Background: Coronavirus disease 2019 (COVID-19) can involve persistence, sequelae, and other clinical complications that last weeks to months to evolve into long COVID-19. Exploratory studies have suggested that interleukin-6 (IL-6) is related to COVID-19; however, the correlation between IL-6 and long COVID-19 is unknown. We designed a systematic review and meta-analysis to assess the relationship between IL-6 levels and long COVID-19.

Methods: Databases were systematically searched for articles with data on long COVID-19 and IL-6 levels published before September 2022. A total of 22 published studies were eligible for inclusion following the PRISMA guidelines. Analysis of data was undertaken by using Cochran’s Q test and the Higgins I-squared (I2) statistic for heterogeneity. Random-effect meta-analyses were conducted to pool the IL-6 levels of long COVID-19 patients and to compare the differences in IL-6 levels among the long COVID-19, healthy, non-postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (non-PASC), and acute COVID-19 populations. The funnel plot and Egger’s test were used to assess potential publication bias. Sensitivity analysis was used to test the stability of the results.

Results: An increase in IL-6 levels was observed after SARS-CoV-2 infection. The pooled estimate of IL-6 revealed a mean value of 20.92 pg/ml (95% CI = 9.30-32.54 pg/ml, I2 = 100%, P < 0.01) for long COVID-19 patients. The forest plot showed high levels of IL-6 for long COVID-19 compared with healthy controls (mean difference = 9.75 pg/ml, 95% CI = 5.75-13.75 pg/ml, I2 = 100%, P < 0.00001) and PASC category (mean difference = 3.32 pg/ml, 95% CI = 0.22-6.42 pg/ml, I2 = 88%, P = 0.04). The symmetry of the funnel plots was not obvious, and Egger’s test showed that there was no significant small study effect in all groups.

Conclusions: This study showed that increased IL-6 correlates with long COVID-19. Such an informative revelation suggests IL-6 as a basic determinant to predict long COVID-19 or at least inform on the “early stage” of long COVID-19.

Source: Yin JX, Agbana YL, Sun ZS, Fei SW, Zhao HQ, Zhou XN, Chen JH, Kassegne K. Increased interleukin-6 is associated with long COVID-19: a systematic review and meta-analysis. Infect Dis Poverty. 2023 Apr 24;12(1):43. doi: 10.1186/s40249-023-01086-z. PMID: 37095536; PMCID: PMC10123579. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10123579/ (Full text)

Deep Phenotyping of Neurologic Postacute Sequelae of SARS-CoV-2 Infection

Abstract:

Background and Objectives SARS-CoV-2 infection has been associated with a syndrome of long-term neurologic sequelae that is poorly characterized. We aimed to describe and characterize in-depth features of neurologic postacute sequelae of SARS-CoV-2 infection (neuro-PASC).

Methods Between October 2020 and April 2021, 12 participants were seen at the NIH Clinical Center under an observational study to characterize ongoing neurologic abnormalities after SARS-CoV-2 infection. Autonomic function and CSF immunophenotypic analysis were compared with healthy volunteers (HVs) without prior SARS-CoV-2 infection tested using the same methodology.

Results Participants were mostly female (83%), with a mean age of 45 ± 11 years. The median time of evaluation was 9 months after COVID-19 (range 3–12 months), and most (11/12, 92%) had a history of only a mild infection. The most common neuro-PASC symptoms were cognitive difficulties and fatigue, and there was evidence for mild cognitive impairment in half of the patients (MoCA score <26). The majority (83%) had a very disabling disease, with Karnofsky Performance Status ≤80. Smell testing demonstrated different degrees of microsmia in 8 participants (66%). Brain MRI scans were normal, except 1 patient with bilateral olfactory bulb hypoplasia that was likely congenital. CSF analysis showed evidence of unique intrathecal oligoclonal bands in 3 cases (25%). Immunophenotyping of CSF compared with HVs showed that patients with neuro-PASC had lower frequencies of effector memory phenotype both for CD4+ T cells (p < 0.0001) and for CD8+ T cells (p = 0.002), an increased frequency of antibody-secreting B cells (p = 0.009), and increased frequency of cells expressing immune checkpoint molecules. On autonomic testing, there was evidence for decreased baroreflex-cardiovagal gain (p = 0.009) and an increased peripheral resistance during tilt-table testing (p < 0.0001) compared with HVs, without excessive plasma catecholamine responses.

Discussion CSF immune dysregulation and neurocirculatory abnormalities after SARS-CoV-2 infection in the setting of disabling neuro-PASC call for further evaluation to confirm these changes and explore immunomodulatory treatments in the context of clinical trials.

Source: Yair Mina, Yoshimi Enose-Akahata, Dima A. Hammoud, Anthony J. Videckis, Sandeep R. Narpala, Sarah E. O’Connell, Robin Carroll, Bob C. Lin, Cynthia Chen McMahan, Govind Nair, Lauren B. Reoma, Adrian B. McDermott, Brian Walitt, Steven Jacobson, David S. Goldstein, Bryan R. Smith, Avindra Nath. Deep Phenotyping of Neurologic Postacute Sequelae of SARS-CoV-2 Infection. Neurol Neuroimmunol Neuroinflamm Jul 2023, 10 (4) e200097; DOI: 10.1212/NXI.0000000000200097 

Risk of autoimmune diseases in patients with COVID-19: A retrospective cohort study

Abstract:

Background: There are a growing number of case reports of various autoimmune diseases occurring after COVID-19, yet there is no large-scale population-based evidence to support this potential association. This study provides a closer insight into the association between COVID-19 and autoimmune diseases and reveals discrepancies across sex, age, and race of participants.

Methods: This is a retrospective cohort study based on the TriNetX U.S. Collaborative Network. In the test-negative design, cases were participants with positive polymerase chain reaction (PCR) test results for SARS-CoV-2, while controls were participants who tested negative and were not diagnosed with COVID-19 throughout the follow-up period. Patients with COVID-19 and controls were propensity score-matched (1: 1) for age, sex, race, adverse socioeconomic status, lifestyle-related variables, and comorbidities. The primary endpoint is the incidence of newly recorded autoimmune diseases. Adjusted hazard ratios (aHRs) and 95% confident intervals (CIs) of autoimmune diseases were calculated between propensity score-matched groups with the use of Cox proportional-hazards regression models.

Findings: Between January 1st, 2020 and December 31st, 2021, 3,814,479 participants were included in the study (888,463 cases and 2,926,016 controls). After matching, the COVID-19 cohort exhibited significantly higher risks of rheumatoid arthritis (aHR:2.98, 95% CI:2.78-3.20), ankylosing spondylitis (aHR:3.21, 95% CI:2.50-4.13), systemic lupus erythematosus (aHR:2.99, 95% CI:2.68-3.34), dermatopolymyositis (aHR:1.96, 95% CI:1.47-2.61), systemic sclerosis (aHR:2.58, 95% CI:2.02-3.28), Sjögren’s syndrome (aHR:2.62, 95% CI:2.29-3.00), mixed connective tissue disease (aHR:3.14, 95% CI:2.26-4.36), Behçet’s disease (aHR:2.32, 95% CI:1.38-3.89), polymyalgia rheumatica (aHR:2.90, 95% CI:2.36-3.57), vasculitis (aHR:1.96, 95% CI:1.74-2.20), psoriasis (aHR:2.91, 95% CI:2.67-3.17), inflammatory bowel disease (aHR:1.78, 95%CI:1.72-1.84), celiac disease (aHR:2.68, 95% CI:2.51-2.85), type 1 diabetes mellitus (aHR:2.68, 95%CI:2.51-2.85) and mortality (aHR:1.20, 95% CI:1.16-1.24).

Interpretation: COVID-19 is associated with a different degree of risk for various autoimmune diseases. Given the large sample size and relatively modest effects these findings should be replicated in an independent dataset. Further research is needed to better understand the underlying mechanisms.

Source: Chang R, Yen-Ting Chen T, Wang SI, Hung YM, Chen HY, Wei CJ. Risk of autoimmune diseases in patients with COVID-19: A retrospective cohort study. EClinicalMedicine. 2023 Feb;56:101783. doi: 10.1016/j.eclinm.2022.101783. Epub 2023 Jan 10. PMID: 36643619; PMCID: PMC9830133. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9830133/ (Full text)