IL-6 drives T cell death to participate in lymphopenia in COVID-19

Therapeutic plasma exchange accelerates immune cell recovery in severe COVID-19

Background

Immunological disturbances (anti-type I IFN auto-antibody production, cytokine storm, lymphopenia, T-cell hyperactivation and exhaustion) are responsible for disease exacerbation during severe COVID-19 infections.

Methods

In this study, we set up a prospective, randomised clinical trial (ClinicalTrials.gov ID: NCT04751643) and performed therapeutic plasma exchange (TPE) in severe COVID-19 patients in order to decrease excess cytokines and auto-antibodies and to assess whether adding TPE to the standard treatment (ST, including corticosteroids plus high-flow rate oxygen) could help restore immune parameters and limit the progression of acute respiratory distress syndrome (ARDS).

Results

As expected, performing TPE decreased the amount of anti-type I IFN auto-antibodies and improved the elimination or limited the production of certain inflammatory mediators (IL-18, IL-7, CCL2, CCL3, etc.) circulating in the blood of COVID-19 patients, compared to ST controls. Interestingly, while TPE did not influence changes in ARDS parameters throughout the protocol, it proved more effective than ST in reversing lymphopenia, preventing T-cell hyperactivation and reducing T-cell exhaustion, notably in a fraction of TPE patients who had an early favourable respiratory outcome. TPE also restored appropriate numbers of CD4+ and CD8+ T-cell memory populations and increased the number of circulating virus-specific T cells in these patients.

Conclusion

Our results therefore indicate that the addition of TPE sessions to the standard treatment accelerates immune cell recovery and contributes to the development of appropriate antiviral T-cell responses in some patients with severe COVID-19 disease.

Blood absolute lymphocyte count and trajectory are important in understanding severe COVID-19

BACKGROUND

Low blood absolute lymphocyte count (ALC) may predict severe COVID-19 outcomes. Knowledge gaps remain regarding the relationship of ALC trajectory with clinical outcomes and factors associated with lymphopenia.

METHODS

Our post hoc analysis of the Therapeutics for Inpatients with COVID-19 platform trial utilized proportional hazards models to assess relationships between Day (D) 0 lymphopenia (ALC < 0.9 cells/uL), D0 severe lymphopenia (ALC < 0.5 cells/uL) or lymphopenia trajectory between D0 and D5 with mortality and secondary infections, and with sustained recovery using Fine-Gray models. Logistic regression was used to assess relationships between clinical variables and D0 lymphopenia or lymphopenia trajectory.

RESULTS

D0 lymphopenia (1426/2579) and severe lymphopenia (636/2579) were associated with increased mortality (aHR 1.48; 1.08, 2.05, p = 0.016 and aHR 1.60; 1.20, 2.14, p = 0.001) and decreased recovery (aRRR 0.90; 0.82, 0.99, p = 0.033 and aRRR 0.78; 0.70, 0.87, p < 0.001 respectively). Trial participants with persistent D5 lymphopenia had increased mortality, and increased secondary infections, and participants with persistent or new lymphopenia had impaired recovery, as compared to participants with no lymphopenia. Persistent and new lymphopenia were associated with older age, male sex; prior immunosuppression, heart failure, aspirin use, and normal body mass index; biomarkers of organ damage (renal and lung), and ineffective immune response (elevated IL-6 and viral nucleocapsid antigen levels). Similar results were observed with severe lymphopenia.

CONCLUSIONS

Lymphopenia was predictive of severe COVID-19 outcomes, particularly when persistent or new during hospitalization. A better understanding of the underlying risk factors for lymphopenia will help illuminate disease pathogenesis and guide management strategies.

CD14loCD301b+ macrophages gathering as a proangiogenic marker in adipose tissues

The role of the monocyte marker CD14 in the regulation of obesity is increasingly recognized. Our observations indicated that Cd14-/- mice exhibited a leaner body shape compared to their wild-type (WT) counterparts. And the loss of CD14 alleviated high-fat diet-induced obesity in mice. In human subjects, CD14 level was tested to be positively correlated with overweight and obesity. However, the relationship between CD14 and the development of obesity remains only partially understood. To investigate the underlying mechanisms, adipose tissues (ATs) from Cd14-/- and WT mice were subjected to deep RNA sequencing. Gene Ontology enrichment analysis revealed a significant enhancement of angiogenesis-related function in the Cd14-/- epididymal adipose tissues compared to WT counterpart, which was accompanied by an upregulation of Cd301b. Subsequent assays confirmed the enhanced angiogenesis and more accumulation of CD301b+ macrophages in Cd14-/- epididymal adipose tissues. Because Igf1 expression has been suggested to be associated with Cd301b expression through pseudotime analysis, we found it was insulin-like growth factor 1 secreted from Cd14-/- macrophages that mediated the angiogenesis enhancement. Collectively, our findings indicate that CD14 deficiency increased the accumulation of CD14loCD301b+ macrophages in ATs, which may serve as a proangiogenic marker, providing novel insights into the relationship between CD14 and obesity development.

Network pharmacology and molecular docking identified IL-6 as a critical target of Qing Yan He Ji against COVID-19

Since the coronavirus disease 2019 (COVID-19) outbreak, although have controlled, severe acute respiratory syndrome coronavirus 2 is constantly mutating and affects people's health. FDA has approved Paxlovid and Molnupiravir for COVID-19 treatment, however, they have not been approved for children under 12 years old. Therefore, it is urgent to explore new drugs for treating COVID-19 in children. As a traditional Chinese medicine, Qing Yan He Ji (QYHJ) has been widely used as an antiviral in our hospital. Therefore, we presumed that it may be ideal for treating COVID-19 and explored its therapeutic effect in patients with COVID-19. The targets and underlying mechanisms of QYHJ against COVID-19 in children were investigated using bioinformatics. QYHJ target sets, and related target genes of COVID-19 were retrieved from public databases. Subsequently, gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to investigate the potential mechanism of QYHJ against COVID-19. Finally, molecular docking was carried out to analyze the affinity between the effective molecule and the target protein. A total of 15 bioactive ingredients of QYHJ and 111 predicted potential targets of QYHJ against COVID-19 were screened. A protein-protein interaction network and subnetworks identified 21 core target genes. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that QYHJ functions against COVID-19 primarily through antiviral and anti-inflammatory effects. Molecular docking of interleukin-6 (IL-6) revealed that 5 active compounds had relatively stable binding activities with IL-6. Molecular dynamics simulation was performed for molecular docking results, showing IL-6-(4aS,6aR,6aS,6bR,8aR,10R,12aR,14bS)-10-hydroxy-2,2,6a,6b,9,9,12a-heptamethyl-1,3,4,5,6,6a,7,8,8a,10,11,12,13,14b-tetradecahydropicene-4a-carboxylic acid (4aS) complex, IL-6-stigmasterol complex, IL-6-poriferasterol complex, IL-6-sitosterol complex, and IL-6-beta-sitosterol complex had relatively good binding stability. In conclusion, the multi-component and multi-target intervention of QYHJ against COVID-19 is closely related to antiviral and anti-inflammatory activities, which provides a theoretical basis for clinical application.

Exploring the interplay between Kaposi's sarcoma and SARS-CoV-2 infection: A case series and systematic review

Kaposi's sarcoma (KS) is an angio-proliferative disease with a viral etiology and a multifactorial pathogenesis that results from immune dysfunction. In patients affected by latent viral infections such as herpesviruses, SARS-CoV-2 infection may result in lytic cycle reactivation in host cells. A robust immune system response is crucial for eliminating pathogens and resolving both latent and non-latent viral infections. We report a case series of KS characterized by tumor progression after SARS-CoV-2 infection. We performed a systematic literature review of the PubMed/MEDLINE and EMBASE databases. The keyword terms included "SARS-CoV-2," "HHV-8," "Kaposi's sarcoma," "IL-6," and "COVID-19." English language restriction was applied. Items not covered by our study were excluded. KS is a complex disease linked to an impaired immune system. Conditions that result in temporary or permanent immunodeficiency can trigger viral reactivation or exacerbate an existing disease. It is feasible that the increase in cytokine levels in COVID-19 patients, coupled with lymphocyte downregulation and treatment that induces herpesvirus lytic reactivation, may contribute to the progression of KS after SARS-CoV-2 infection. These observations suggest that patients with KS should be clinically monitored both during and after SARS-CoV-2 infection. Nevertheless, prospective data should be collected to validate this hypothesis and enhance our understanding of the mechanisms implicated in the onset or progression of KS.

R-ketorolac ameliorates cancer-associated cachexia and prolongs survival of tumour-bearing mice

BACKGROUND

Cancer-associated cachexia (CAC) is a debilitating syndrome associated with poor quality of life and reduced life expectancy of cancer patients. CAC is characterized by unintended body weight reduction due to muscle and adipose tissue loss. A major hallmark of CAC is systemic inflammation. Several non-steroidal anti-inflammatory drugs (NSAIDs) have been suggested for CAC treatment, yet no single medication has proven reliable. R-ketorolac (RK) is the R-enantiomer of a commonly used NSAID. The effect of RK on CAC has not yet been evaluated.

METHODS

Ten- to 11-week-old mice were inoculated with C26 or CHX207 cancer cells or vehicle control (phosphate-buffered saline [PBS]). After cachexia onset, 2 mg/kg RK or PBS was administered daily by oral gavage. Body weight, food intake and tumour size were continuously measured. At study endpoints, blood was drawn, mice were sacrificed and tissues were excised. Immune cell abundance was analysed using a Cytek® Aurora spectral flow cytometer. Cyclooxygenase (COX) activity was determined in lung homogenates using a fluorometric kit. Muscle tissues were analysed for mRNA and protein expression by quantitative real-time PCR and western blotting analysis, respectively. Muscle fibre size was determined on histological slides after haematoxylin/eosin staining.

RESULTS

Ten-day survival rate of C26-bearing animals was 10% while RK treatment resulted in a 100% survival rate (P = 0.0009). Chemotherapy resulted in a 10% survival rate 14 days after treatment initiation, but all mice survived upon co-medication with RK and cyclophosphamide (P = 0.0001). Increased survival was associated with a protection from body weight loss in C26 (-0.61 ± 1.82 vs. -4.48 ± 2.0 g, P = 0.0004) and CHX207 (-0.49 ± 0.33 vs. -2.49 ± 0.93 g, P = 0.0003) tumour-bearing mice treated with RK, compared with untreated mice. RK ameliorated musculus quadriceps (-1.7 ± 7.1% vs. -27.8 ± 8.3%, P = 0.0007) and gonadal white adipose tissue (-18.8 ± 49% vs. -69 ± 15.6%, P = 0.094) loss in tumour-bearing mice, compared with untreated mice. Mechanistically, RK reduced circulating interleukin-6 (IL-6) concentrations from 334 ± 151 to 164 ± 123 pg/mL (P = 0.047) in C26 and from 93 ± 39 to 35 ± 6 pg/mL (P = 0.0053) in CHX207 tumour-bearing mice. Moreover, RK protected mice from cancer-induced T-lymphopenia (+1.8 ± 42% vs. -49.2 ± 12.1% in treated vs. untreated mice, respectively). RK was ineffective in ameliorating CAC in thymus-deficient nude mice, indicating that the beneficial effect of RK depends on T-cells.

CONCLUSIONS

RK improved T-lymphopenia and decreased systemic IL-6 concentrations, resulting in alleviation of cachexia and increased survival of cachexigenic tumour-bearing mice, even under chemotherapy and independent of COX inhibition. Considering its potential, we propose that the use of RK should be investigated in patients suffering from CAC.

Severe COVID-19 and long COVID are associated with high expression of STING, cGAS and IFN-α

The cGAS-STING pathway appears to contribute to dysregulated inflammation during coronavirus disease 2019 (COVID-19); however, inflammatory factors related to long COVID are still being investigated. In the present study, we evaluated the association of cGAS and STING gene expression levels and plasma IFN-α, TNF-α and IL-6 levels with COVID-19 severity in acute infection and long COVID, based on analysis of blood samples from 148 individuals, 87 with acute COVID-19 and 61 in the post-COVID-19 period. Quantification of gene expression was performed by real-time PCR, and cytokine levels were quantified by ELISA and flow cytometry. In acute COVID-19, cGAS, STING, IFN-α, TNF-α, and IL-6 levels were higher in patients with severe disease than in those with nonsevere manifestations (p < 0.05). Long COVID was associated with elevated cGAS, STING and IFN-α levels (p < 0.05). Activation of the cGAS-STING pathway may contribute to an intense systemic inflammatory state in severe COVID-19 and, after infection resolution, induce an autoinflammatory disease in some tissues, resulting in long COVID.

Unveiling COVID-19 Secrets: Harnessing Cytokines as Powerful Biomarkers for Diagnosis and Predicting Severity

Introduction

In coronavirus disease (COVID-19), inflammation takes center stage, with a cascade of cytokines released, contributing to both inflammation and lung damage. The objective of this study is to identify biomarkers for diagnosing and predicting the severity of COVID-19.

Materials and Methods

Cytokine levels were determined in the serum from venous blood samples collected from 100 patients with COVID-19 and 50 healthy controls. COVID-19 patients classified based on the Modified Early Warning (MEWS) score. Cytokine concentrations were determined with a multiplex ELISA kit (Bio-Plex Pro™ Human Cytokine Screening Panel).

Results

The concentrations of all analyzed cytokines were elevated in the serum of COVID-19 patients relative to the control group, but no significant differences were observed in interleukin-9 (IL-9) and IL-12 p70 levels. In addition, the concentrations of IL-1α, IL-1β, IL-1ra, IL-2Rα, IL-6, IL-12 p40, IL-18, and tumor necrosis factor alpha (TNFα) were significantly higher in symptomatic patients with accompanying pneumonia without respiratory failure (stage 2) than in asymptomatic/mildly symptomatic patients (stage 1).

Conclusion

The study revealed that IL-1ra, IL-2Rα, IL-6, IL-8, IL-12 p40, IL-16, and IL-18 levels serve as potential diagnostic biomarkers in COVID-19 patients. Furthermore, elevated IL-1α levels proved to be valuable in assessing the severity of COVID-19.

Differentially Expressed Inflammatory Cell Death-Related Genes and the Serum Levels of IL-6 are Determinants for Severity of Coronaviruses Diseases-2019 (COVID-19)

Background

Inflammatory cell death, PANoptosis, has been suggested to orchestrate the lymphocyte decrement among coronavirus disease-2019 (COVID-19) patients. The main aim of this study was to examine the differences in the expression of key genes related to inflammatory cell death and their correlation with lymphopenia in the mild and severe types of COVID-19 patients.

Materials and Methods

Eighty-eight patients (36 to 60 years old) with mild (n = 44) and severe (n = 44) types of COVID-19 were enrolled. The expression of key genes related to apoptosis (FAS-associated death domain protein, FADD), pyroptosis (ASC (apoptosis-associated speck-like protein containing caspase activation and recruitment domains (CARD)), the adapter protein ASC binds directly to caspase-1 and is critical for caspase-1 activation in response to a broad range of stimuli), and necroptosis (mixed lineage kinase domain-like, MLKL) genes were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay, and compared between the groups. The serum levels of interleukin (IL)-6 were measured by enzyme-linked immunosorbent assay (ELISA) assay.

Results

A major increase in the expression of FADD, ASC, and MLKL-related genes in the severe type of patients was compared to the mild type of patients. The serum levels of IL-6 similarly indicated a significant increase in the severe type of the patients. A significant negative correlation was detected between the three genes' expression and the levels of IL-6 with the lymphocyte counts in both types of COVID-19 patients.

Conclusion

Overall, the main regulated cell-death pathways are likely to be involved in lymphopenia in COVID-19 patients, and the expression levels of these genes could potentially predict the patients' outcome.

The immune paradox of SARS-CoV-2: Lymphocytopenia and autoimmunity evoking features in COVID-19 and possible treatment modalities

SARS-CoV-2 causes multiorgan damage to vital organs and tissue that are known to be due to a combination of tissue tropisms and cytokine-mediated damage that it can incite in COVID-19. The effects of SARS-Co-2 on the lymphocytes and therefore on the immune response have attracted attention recently in COVID-19 to understand its effects in causing a chronic state of ongoing infection with Long-COVID. The associated lymphopaenia and autoimmune disease state, which is an apparent paradox, needs to be researched to dissect possible mechanisms underlying this state. This paper attempts to unravel the aforesaid immune paradox effects of SARS-CoV-2 on the lymphocytes and discusses appropriate treatment modalities with antiviral drugs and nutraceuticals which could prove virucidal in SARS-CoV-2 seeding monocytes and lymphocytes in patients with COVID-19 and Long-COVID. Importantly it proposes a new in vitro treatment modality of immune regulating cells that can help patients fight the lymphopaenia associated with COVID-19 and Long-COVID.