Role of immune mediators in predicting hospitalization of SARS-CoV-2 positive patients

Nebulized glycyrrhizin/enoxolone drug modulates IL-17A in COVID-19 patients: a randomized clinical trial

Introduction

Glycyrrhizin (GA) and its derivative Enoxolone (18β), isolated from the Glycyrrhiza glabra plant, are two potential molecules for treating viral diseases. Both demonstrate to regulate immune system with antiviral and anti-inflammatory activities, with the latter mainly due to modulation of inflammatory cytokines. The aim of this clinical trial was to evaluate the safety and efficacy of a nebulized GA/18β drug for treating COVID-19 patients.

Methods

An open label, randomized, placebo-controlled clinical trial was conducted in Mexico City from January-August 2022 (Registration No. PROTAP-CLI-00). Clinical and biochemical parameters were recorded. Blood samples from patients were regularly collected to evaluate interleukins IL-4, IL-2, IL-1b, TNF-α, IL-17A, IL-6, IL-10,IFN-γ, IL-12, IL-8 and TGF-β1, as well as IgM and IgG against SARS-CoV-2. Two doses of the drug were used - 30/2 mg (dose A) and 90/4 mg (dose B).

Results and discussion

Both GA/18β doses modulated inflammatory response by reducing mainly IL-17A expression, which in turn kept IL-1β, IL-6, IL-8 and TNF-α interleukins unchanged, indicating significant modulation of key interleukin levels to prevent exacerbation of the immune response in COVID-19 patients. Early on, dose A increased IgM, while dose B induced expression of the antiviral IFN-γ. No severe side effects were seen with either dose, indicating nebulized GA/18β is a safe treatment that could be used for COVID-19 and potentially other viral infections involving inflammatory response.

Enhancement of IL-6 Production Induced by SARS-CoV-2 Nucleocapsid Protein and Bangladeshi COVID-19 Patients' Sera

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by severe acute respiratory syndrome coronavirus 2 that can have detrimental effects on multiple organs and accelerate patient mortality. This study, which encompassed 130 confirmed COVID-19 patients who were assessed at three different time points (i.e., 3, 7, and 12 days) after the onset of symptoms, investigated interleukin-6 (IL-6) enhancement induced by a viral nucleocapsid (N) protein from a myeloid cell line. Disease severity was categorized as mild, moderate, or severe. The severe cases were characterized as having significant elevations in serum IL-6, C-reactive protein, D-dimer, ferritin, creatinine, leukocytes, and neutrophil-to-lymphocyte ratio and decreased hemoglobin, hematocrit, and albumin levels compared with mild and moderate cases. To evaluate IL-6-inducing activity, heat-inactivated sera from these patients were incubated with and without the N protein. The findings showed a progressive increase in IL-6 production in severe cases upon N protein stimulation. There was a strong correlation between anti-N antibodies and levels of IL-6 secreted by myeloid cells in the presence of N protein and sera, indicating the crucial role that the anti-N antibody plays in inducing IL-6 production. Uncontrolled IL-6 production played a pivotal role in disease pathogenesis, exacerbating both disease severity and mortality. Efficiently targeting the N protein could potentially be employed as a therapeutic strategy for regulating the immune response and alleviating inflammation in severe cases.

Tools and factors predictive of the severity of COVID-19

The outbreak of the novel coronavirus infection caused worldwide confusion. The problem with this infection is that it causes severe illness in some patients, resulting in a high rate of death if appropriate treatment is not given. If patients with severe illness that requires treatment are appropriately identified, treatment can be focused on these patients. However, in the early days of the COVID-19 outbreak, the inability to predict and diagnose the disease led to hospitals being overwhelmed. Therefore, various methods for the diagnosis of severe disease were developed early on, and various methods are still being investigated to predict high-risk patients. The currently available prediction methods are divided into those that predict the onset of severe disease and those used to determine the severity of the disease. Specifically, the main methods include genetic factors, serum humoral factors, laboratory tests, and diagnostic imaging. Since each of these factors has different features, using them in combination is likely to be advantageous.

The Impact of Therapeutic Plasma Exchange on Inflammatory Markers and Acute Phase Reactants in Patients with Severe SARS-CoV-2 Infection

Background and Objectives: Due to the poor prognosis and the very high mortality rate associated with severe SARS-CoV-2 infections, various regimens have been tried to stop the evolution of the inflammatory cascade, such as immunomodulatory therapy and plasma clearance of the acute phase reactants involved. Therefore, the objective of this review was to analyze the effects of using therapeutic plasma exchange (TPE), also known as plasmapheresis, on the inflammatory markers of critically ill COVID-19 patients admitted to the intensive care unit (ICU). Materials and Methods: A thorough scientific database search was performed, and it included a review of articles published on PubMed, Cochrane Database, Scopus, and Web of Science from the beginning of the COVID-19 pandemic in March 2020 until September 2022 that focused on the treatment of SARS-CoV-2 infections using plasma exchange for patients admitted to the ICU. The current study included original articles, reviews, editorials, and short or special communications regarding the topic of interest. Results: A total of 13 articles were selected after satisfying the inclusion criterion of three or more patients enrolled with clinically severe COVID-19 that were eligible for TPE. From the included articles, it was observed that TPE was used as a last-resort salvage therapy that can be regarded as an alternative treatment method when the standard management for these patients fails. TPE significantly decreased the inflammatory status as measured by Interleukin-6 (IL-6), C-reactive protein (CRP), lymphocyte count, and D-dimers, as well as improving the clinical status measured with PaO₂/FiO₂ and duration of hospitalization. The pooled mortality risk reduction after TPE was 20%. Conclusions: There are sufficient studies and evidence to show that TPE reduces inflammatory mediators and improves coagulation function and the clinical/paraclinical status. Nevertheless, although it was shown that TPE decreases the severe inflammatory status without significant complications, the improvement of survival rate remains unclear.

Assessing the Outcomes of Patients with Severe SARS-CoV-2 Infection after Therapeutic Plasma Exchange by Number of TPE Sessions

The high mortality risk in severe SARS-CoV-2 infections is tightly correlated to the extreme elevation of inflammatory markers. This acute accumulation of inflammatory proteins can be cleared using plasma exchange (TPE), commonly known as plasmapheresis, although the available data on performing TPE in COVID-19 patients is limited regarding the optimal treatment protocol. The purpose for this study was to examine the efficacy and outcomes of TPE based on different treatment methods. A thorough database search was performed to identify patients from the Intensive Care Unit (ICU) of the Clinical Hospital of Infectious Diseases and Pneumology between March 2020 and March 2022 with severe COVID-19 that underwent at least one session of TPE. A total of 65 patients satisfied the inclusion criteria and were eligible for TPE as a last resort therapy. Of these, 41 patients received 1 TPE session, 13 received 2 TPE sessions, and the remaining 11 received more than 2 TPE sessions. It was observed that IL-6, CRP, and ESR decreased significantly after all sessions were performed in all three groups, with the highest decrease of IL-6 in those who received >2 TPE sessions (from 305.5 pg/mL to 156.0 pg/mL). Interestingly, there was a significant increase in leucocyte levels after TPE, but there was no significant difference in MAP changes, SOFA score, APACHE 2 score, or the PaO2/FiO2 ratio. The ROX index was significantly higher among the patients who underwent more than two TPE sessions, with an average of 11.4, compared to 6.5 in group 1 and 7.4 in group 2, which increased significantly after TPE. Nevertheless, the mortality rate was very high (72.3%), and the Kaplan-Meier analysis identified no significant difference in survival according to the number of TPE sessions. TPE can be used as last resort salvage therapy that can be regarded as an alternative treatment method when the standard management of these patients fails. It significantly decreases the inflammatory status measured via IL-6, CRP, and WBC, as well as demonstrating an improvement of the clinical status measured via PaO2/FiO2, and duration of hospitalization. However, the survival rate does not seem to change with the number of TPE sessions. Based on the survival analysis, one session of TPE as last resort treatment in patients with severe COVID-19 proved to have the same effect as repeated TPE sessions of 2 or more.

SARS-CoV-2 infection of intestinal epithelia cells sensed by RIG-I and DHX-15 evokes innate immune response and immune cross-talk

SARS-CoV-2 causes a spectrum of clinical symptoms from respiratory damage to gastrointestinal disorders. Intestinal infection of SARS-CoV-2 triggers immune response. However, the cellular mechanism that how SARS-CoV-2 initiates and induces intestinal immunity is not understood. Here, we exploited SARS-CoV-2-GFP/ΔN trVLP pseudo-virus system and demonstrated that RIG-I and DHX15 are required for sensing SARS-CoV-2 and inducing cellular immune response through MAVS signaling in intestinal epithelial cells (IECs) upon SARS-CoV-2 infection. NLRP6 also engages in the regulation of SARS-CoV-2 immunity by producing IL-18. Furthermore, primary cellular immune response provoked by SARS-CoV-2 in IECs further cascades activation of MAIT cells and produces cytotoxic cytokines including IFN-γ, granzyme B via an IL-18 dependent mechanism. These findings taken together unveil molecular basis of immune recognition in IECs in response to SARS-CoV-2, and provide insights that intestinal immune cross-talk with other immune cells triggers amplified immunity and probably contributes to immunopathogenesis of COVID-19.

Cytokine levels associated with favorable clinical outcome in the CAPSID randomized trial of convalescent plasma in patients with severe COVID-19

Objectives

To determine the profile of cytokines in patients with severe COVID-19 who were enrolled in a trial of COVID-19 convalescent plasma (CCP).

Methods

Patients were randomized to receive standard treatment and 3 CCP units or standard treatment alone (CAPSID trial, ClinicalTrials.gov NCT04433910). The primary outcome was a dichotomous composite outcome (survival and no longer severe COVID-19 on day 21). Time to clinical improvement was a key secondary endpoint. The concentrations of 27 cytokines were measured (baseline, day 7). We analyzed the change and the correlation between serum cytokine levels over time in different subgroups and the prediction of outcome in receiver operating characteristics (ROC) analyses and in multivariate models.

Results

The majority of cytokines showed significant changes from baseline to day 7. Some were strongly correlated amongst each other (at baseline the cluster IL-1ß, IL-2, IL-6, IL-8, G-CSF, MIP-1α, the cluster PDGF-BB, RANTES or the cluster IL-4, IL-17, Eotaxin, bFGF, TNF-α). The correlation matrix substantially changed from baseline to day 7. The heatmaps of the absolute values of the correlation matrix indicated an association of CCP treatment and clinical outcome with the cytokine pattern. Low levels of IP-10, IFN-γ, MCP-1 and IL-1ß on day 0 were predictive of treatment success in a ROC analysis. In multivariate models, low levels of IL-1ß, IFN-γ and MCP-1 on day 0 were significantly associated with both treatment success and shorter time to clinical improvement. Low levels of IP-10, IL-1RA, IL-6, MCP-1 and IFN-γ on day 7 and high levels of IL-9, PDGF and RANTES on day 7 were predictive of treatment success in ROC analyses. Low levels of IP-10, MCP-1 and high levels of RANTES, on day 7 were associated with both treatment success and shorter time to clinical improvement in multivariate models.

Conclusion

This analysis demonstrates a considerable dynamic of cytokines over time, which is influenced by both treatment and clinical course of COVID-19. Levels of IL-1ß and MCP-1 at baseline and MCP-1, IP-10 and RANTES on day 7 were associated with a favorable outcome across several endpoints. These cytokines should be included in future trials for further evaluation as predictive factors.

Anti-nucleocapsid antibodies enhance the production of IL-6 induced by SARS-CoV-2 N protein

A cytokine storm induces acute respiratory distress syndrome, the main cause of death in coronavirus disease 2019 (COVID-19) patients. However, the detailed mechanisms of cytokine induction due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain unclear. To examine the cytokine production in COVID-19, we mimicked the disease in SARS-CoV-2-infected alveoli by adding the lysate of SARS-CoV-2-infected cells to cultured macrophages or induced pluripotent stem cell-derived myeloid cells. The cells secreted interleukin (IL)-6 after the addition of SARS-CoV-2-infected cell lysate. Screening of 25 SARS-CoV-2 protein-expressing plasmids revealed that the N protein-coding plasmid alone induced IL-6 production. The addition of anti-N antibody further enhanced IL-6 production, but the F(ab')² fragment did not. Sera from COVID-19 patients also enhanced IL-6 production, and sera from patients with severer disease induced higher levels of IL-6. These results suggest that anti-N antibody promotes IL-6 production in SARS-CoV-2-infected alveoli, leading to the cytokine storm of COVID-19.