COVID-19: Imbalanced Immune Responses and Potential Immunotherapies

SARS-CoV-2 infection threatening intestinal health: A review of potential mechanisms and treatment strategies

The outbreak of the COVID-19 pandemic has brought great problems to mankind, including economic recession and poor health. COVID-19 patients are frequently reported with gastrointestinal symptoms such as diarrhea and vomiting in clinical diagnosis. Maintaining intestinal health is the key guarantee to maintain the normal function of multiple organs, otherwise it will be a disaster. Therefore, the purpose of this review was deeply understanded the potential mechanism of SARS-CoV-2 infection threatening intestinal health and put forward reasonable treatment strategies. Combined with the existing researches, we summarized the mechanism of SARS-CoV-2 infection threatening intestinal health, including intestinal microbiome disruption, intestinal barrier dysfunction, intestinal oxidative stress and intestinal cytokine storm. These adverse intestinal events may affect other organs through the circulatory system or aggravate the course of the disease. Typically, intestinal disadvantage may promote the progression of SARS-CoV-2 through the gut-lung axis and increase the disease degree of COVID-19 patients. In view of the lack of specific drugs to inhibit SARS-CoV-2 replication, the current review described new strategies of probiotics, prebiotics, postbiotics and nutrients to combat SARS-CoV-2 infection and maintain intestinal health. To provide new insights for the prevention and treatment of gastrointestinal symptoms and pneumonia in patients with COVID-19.

Predicting oxygen requirements in patients with coronavirus disease 2019 using an artificial intelligence-clinician model based on local non-image data

BACKGROUND

When facing unprecedented emergencies such as the coronavirus disease 2019 (COVID-19) pandemic, a predictive artificial intelligence (AI) model with real-time customized designs can be helpful for clinical decision-making support in constantly changing environments. We created models and compared the performance of AI in collaboration with a clinician and that of AI alone to predict the need for supplemental oxygen based on local, non-image data of patients with COVID-19.

MATERIALS AND METHODS

We enrolled 30 patients with COVID-19 who were aged >60 years on admission and not treated with oxygen therapy between December 1, 2020 and January 4, 2021 in this 50-bed, single-center retrospective cohort study. The outcome was requirement for oxygen after admission.

RESULTS

The model performance to predict the need for oxygen by AI in collaboration with a clinician was better than that by AI alone. Sodium chloride difference >33.5 emerged as a novel indicator to predict the need for oxygen in patients with COVID-19. To prevent severe COVID-19 in older patients, dehydration compensation may be considered in pre-hospitalization care.

CONCLUSION

In clinical practice, our approach enables the building of a better predictive model with prompt clinician feedback even in new scenarios. These can be applied not only to current and future pandemic situations but also to other diseases within the healthcare system.

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio Can Predict the Severity in COVID-19 Patients from Ethiopia: A Retrospective Study

Background

Coronaviruses are a broad family of pathogens that can cause mild to severe respiratory illnesses. Due to a strong inflammatory response and a weak immunological response, viral pneumonia inflammation, like Coronavirus Disease 2019 (COVID-19), displays an unbalanced immune response. Therefore, circulating biomarkers of inflammation and the immune system can serve as reliable predictors of a patient's prognosis for COVID-19. Hematological ratios are reliable markers of inflammation that are frequently utilized in pneumonia, primarily in viral infections with low cost in developing countries.

Purpose

To examine the neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) in predicting the severity of COVID-19 patients.

Methods

An institutional-based retrospective study was done on 105 hospitalized COVID-19 patients at the University of Gondar comprehensive specialized referral hospital, Northwest Ethiopia. The laboratory evaluations that were gathered, evaluated, and reported on included the total leucocyte count (TLC), absolute neutrophil count (ANC), absolute lymphocyte count (ALC), absolute monocyte count (AMC), NLR, LMR, and PLR. The Kruskal-Wallis test and Wilcoxon matched-pairs signed test were used to see whether there were any differences between the continuous variables. Receiver operating curve (ROC) analysis was used to determine the appropriate cut-off values for NLR, PLR, and LMR. P-value <0.05 was considered a statistically significant association.

Results

ANC, NLR, and PLR were highest in the critical group (p = 0.001), while this group had the least ALC and LMR (p = 0.001). We calculated the optimal cut-off values of the hematological ratios; NLR (8.4), LMR (1.4), and PLR (18.0). NLR had the highest specificity and sensitivity, at 83.8% and 80.4%, respectively.

Conclusion

Our research showed that NLR and PLR were good indicators of severity in COVID-19. However, our findings indicate that MLR is not a reliable predictor.

Antibody Therapy for COVID-19: Categories, Pros, and Cons

COVID-19 is a life-threatening respiratory disease triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has been considered a pandemic viral infection since December 2019. The investigation of the effective prophylaxis or therapeutic strategies for emergency management of the current condition has become a priority for medical research centers and pharmaceutical companies. This article provides a comprehensive review of antibody therapy and its different categories with their advantages and disadvantages for COVID-19 over the last few years of the current pandemic. Antibodies can be generated by active immunization, including natural infection with a pathogen and vaccination, or by the passive immunization method such as convalescent plasma therapy (CPT) and antibody synthesis in laboratories. Each of these ways has its characteristics. Arming the immune system with antibodies is the main aim of antiviral therapeutic procedures toward SARS-CoV-2. Collecting and discussing various aspects of available data in this field can give researchers a better perspective for the production of antibody-based products or selection of the most appropriate approach of antibody therapies to improve different cases of COVID-19. Moreover, it can help them control similar viral pandemics that may happen in the future appropriately.

Is IFN expression by NK cells a hallmark of severe COVID-19?

Natural Killer cells (NK) are crucial in host defense against viruses. There are many unanswered questions about the immune system in COVID-19, especially the mechanisms that contribute to the development of mild or severe forms of the disease. Although NK cells may have an essential role in the pathogenesis of COVID-19, the mechanisms involved in this process are not yet fully elucidated. Here, we demonstrate that CD3^-CD56⁺ NK cells frequency in the volunteers who recovered from mild COVID-19 (Mild CoV) presented a significant increase compared to the healthy control (HC) and individuals recovering from severe COVID-19 (Severe CoV) groups. Furthermore, distinct IFN profiles in recovered COVID-19 patients with mild or severe clinical forms of the disease were observed in the total NK cells (CD3^-CD56⁺). In the first group, NK cells express increased levels of IFN-α compared to the severe CoV, while higher production of IFN-γ in severe CoV was found. Moreover, NK cells in mild CoV express more cytolytic granules depicted by granzyme B and perforin. Compared to HC, PBMCs from mild CoV presented higher Ki-67 and TIM-3 production after Pool CoV-2 and Pool Spike CoV-2 peptides stimulus. In addition, non-stimulated PBMCs in the mild CoV group had higher NK TIM-3+ frequency than severe CoV. In the mild CoV group, Pool Spike CoV-2 and Pool CoV-2 peptides stimuli elicited higher granzyme B and perforin coexpression and IFN-α production by PBMCs. However, in severe CoV, Pool Spike CoV-2 reduced the coexpression of granzyme B, perforin, and CD107a suggesting a decrease in the cytotoxic activity of NK cells. Therefore, our study shows that NK cells may have a crucial role in COVID-19 with the involvement of IFN-α and cytotoxic properties that aid in developing qualified immune responses. Furthermore, the data suggest that higher amounts of IFN-γ may be linked to the severity of this disease.

Kinetics of Severity Biomarkers and Immunological Features of Methylprednisolone Therapy for Severe COVID-19 Patients

In contrast to dexamethasone, the clinical efficacy of methylprednisolone (MP) remains controversial, and a systems biology study on its mechanism is lacking. In this study, a total of 38 severe COVID-19 patients were included. The demographics, clinical characteristics, and severity biomarkers including C-reactive protein (CRP), d-dimer, albumin, and Krebs von den Lungen 6 of patients receiving MP (n=26, 40 mg or 80 mg daily for 3-5 days) and supportive therapy (n=12) were compared. Longitudinal measurements of 92 cytokines in MP group from admission to over six months after discharge were performed by multiplex Proximity Extension Assay. The results showed that demographics, baseline clinical characteristics were similar in MP and non-MP groups. No death occurred and the hospital stays between the two groups were similar. Kinetics studies showed that MP was not better than supportive therapy at improving the four severity biomarkers. Cytokines in MP group were characterized by five clusters according to their baseline levels and responses to MP. The immunological feature of severe COVID-19 could be defined by the “core signature” cytokines in cluster 2: MCP-3, IL-6, IFN-γ, and CXCL10, which strongly correlated with each other and CRP, and are involved in cytokine release storm. The “core signature” cytokines were significantly upregulated at baseline and remained markedly elevated after MP treatment. Our work showed a short course of MP therapy could not rapidly improve the immune disorders among severe COVID-19 patients or clinical outcomes, also confirmed “core signature” cytokines, as severity biomarkers similar to CRP, could be applied to evaluate clinical treatment effect.

Kidney implications of SARS-CoV2 infection in children

Research indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection can impact every organ, and the effects can range from asymptomatic to severe disease. Since it was first discovered in December 2019, our understanding has grown about its impact on kidney disease. In general, children have less severe disease than adults, and this tendency appears to extend to special pediatric kidney populations (e.g., chronic kidney disease and immunosuppressed patients with solid organ transplants or nephrotic syndrome). However, in a fraction of infected children, SARS-CoV2 causes an array of kidney manifestations, ranging from acute kidney injury to thrombotic microangiopathy, with potential implications for increased risk of morbidity and mortality. Additional considerations surround the propensity for clotting extracorporeal circuits in children with SARS-CoV2 infection that are receiving kidney replacement therapy. This review provides an update on our current understanding of SARS-CoV2 for pediatric nephrologists and highlights knowledge gaps to be addressed by future research during this ongoing pandemic, particularly the social disparities magnified during this period.

The Role of BPIFB4 in Immune System and Cardiovascular Disease: The Lesson from Centenarians

Recent discoveries have shed light on the participation of the immune system in the physio pathology of the cardiovascular system underpinning the importance of keeping the balance of the first to preserve the latter. Aging, along with other risk factors, can challenge such balance triggering the onset of cardiovascular diseases. Among several mediators ensuring the proper cross-talk between the two systems, bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4) has been shown to have a pivotal role, also by sustaining important signals such as eNOS and PKC-alpha. In addition, the Longevity-associated variant (LAV), which is an haplotype allele in BPIFB4 characterized by 4 missense polymorphisms, enriched in homozygosity in Long Living Individuals (LLIs), has been shown to be efficient, if administered systemically through gene therapy, in improving many aspects of cardiovascular diseases (CVDs). This occurs mainly through a fine immune system remodeling across: 1) a M2 macrophage polarizing effect, 2) a favorable redistribution of the circulating monocyte cell subsets and 3) the reduction of T-cell activation. Furthermore, LAV-BPIFB4 treatment induced a desirable recovery of the inflammatory balance by mitigating the pro-inflammatory factor levels and enhancing the anti-inflammatory boost through a mechanism that is partially dependent on SDF-1/CXCR4 axis. Importantly, the remarkable effects of LAV-BPIFB4 treatment, which translates in increased BPIFB4 circulating levels, mirror what occurs in long-living individuals (LLIs) in whom the high circulating levels of BPIFB4 are protective from age-related and CVDs and emphasize the reason why LLIs are considered a model of successful aging. Here, we review the mechanisms by which LAV-BPIFB4 exerts its immunomodulatory activity in improving the cardiovascular-immune system dialogue that might strengthen its role as a key mediator in CVDs.

Corticosteroids May Have Negative Effects on the Management of Patients with Severe Fever with Thrombocytopenia Syndrome: A Case-Control Study

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral hemorrhagic fever in China, Korea, and Japan. To date, no standardized treatment protocol for SFTS has been established. Corticosteroids (CS) may be administered to patients with SFTS and hemophagocytic syndrome, but its effectiveness and safety are still debatable. We conducted a retrospective case series review at four medical facilities in Miyazaki, Japan. Based on the medical records, clinical data, including the patients background, symptoms, physical findings, laboratory data at initial presentation, treatment, and outcome, were compared between the CS-treated and the non-CS-treated group. A total of 47 patients with confirmed SFTS in each hospital were enrolled in this study; there were 14 fatal cases and 33 nonfatal cases. The case fatality ratio was 29.8%. After adjusting patients' background by propensity score matching, the case fatality ratio was higher (p = 0.04) and complications of secondary infections, including invasive pulmonary aspergillosis, tended to be more frequent (p = 0.07) in the CS-treated group than in the non-CS-treated group. These data suggested that administration of CS to patients with SFTS should be carefully considered.

An Updated Review of SARS-CoV-2 Vaccines and the Importance of Effective Vaccination Programs in Pandemic Times

Since the worldwide COVID-19 pandemic was declared a year ago, the search for vaccines has become the top priority in order to restore normalcy after 2.5 million deaths worldwide, overloaded sanitary systems, and a huge economic burden. Vaccine development has represented a step towards the desired herd immunity in a short period of time, owing to a high level of investment, the focus of researchers, and the urge for the authorization of the faster administration of vaccines. Nevertheless, this objective may only be achieved by pursuing effective strategies and policies in various countries worldwide. In the present review, some aspects involved in accomplishing a successful vaccination program are addressed, in addition to the importance of vaccination in a pandemic in the face of unwillingness, conspiracy theories, or a lack of information among the public. Moreover, we provide some updated points related to the landscape of the clinical development of vaccine candidates, specifically, the top five vaccines that are already being assessed in Phase IV clinical trials (BNT162b2, mRNA-1273, AZD1222, Ad26.COV2.S, and CoronaVac).