Reduction and exhausted features of T lymphocytes under serological changes, and prognostic factors in COVID-19 progression

The underlying mechanism behind the different outcomes of COVID-19 in children and adults

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has affected hundreds of millions of people globally, resulting in millions of deaths. During this pandemic, children have demonstrated greater resistance than adults, exhibiting lower infection rates, reduced mortality, and milder symptoms. Summarizing the differences in resistance between children and adults during COVID-19 can provide insights into protective mechanisms and potential implications for future treatments. In this review, we focused on summarizing and discussing the mechanisms for better protection of children in COVID-19. These protective mechanisms encompass several factors: the baseline expression of cell surface receptor ACE2 and hydrolase TMPRSS2, the impact of complications on COVID-19, and age-related cytokine profiles. Additionally, differences in local and systemic immune responses between children and adults also contribute significantly, particularly interferon responses, heterologous protection from non-COVID-19 vaccinations, and immune status variations influenced by micronutrient levels. The advantageous protection mechanisms of these children may provide insights into the prevention and treatment of COVID-19. Importantly, while age-related metabolic profiles and differential COVID-19 vaccine responses may contribute to protection in children, current comparative research remains limited and requires further investigation.

Navigating SARS-CoV-2-related immunopathology in Crohn's disease: from molecular mechanisms to therapeutic challenges

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) not only posed major health and economic burdens to international societies but also threatens patients with comorbidities and underlying autoimmune disorders, including Crohn's disease (CD) patients. As the vaccinated population is gradually relieved from the stress of the latest omicron variant of SARS-CoV-2 due to competent immune responses, the anxiety of CD patients, especially those on immunosuppressive treatment, has not subsided. Whether the use of immunosuppressants for remission of CD outweighs the potential risk of severe coronavirus disease 2019 (COVID-19) has long been discussed. Thus, for the best benefit of CD patients, our primary goal in this study was to navigate the clinical management of CD during the COVID pandemic. Herein, we summarized COVID-19 outcomes of CD patients treated with immunosuppressive agents from multiple cohort studies and also investigated possible mechanisms of how SARS-CoV-2 impacts the host immunity with special consideration of CD patients. We first looked into the SARS-CoV-2-related immunopathology, including lymphocytopenia, T-cell exhaustion, cytokine storms, and their possible molecular interactions, and then focused on mechanistic actions of gastrointestinal systems, including interruption of tryptophan absorption, development of dysbiosis, and consequent local and systemic inflammation. Given challenges in managing CD, we summarized up-to-date clinical and molecular evidence to help physicians adjust therapeutic strategies to achieve the best clinical outcomes for CD patients.

The severity assessment and nucleic acid turning-negative-time prediction in COVID-19 patients with COPD using a fused deep learning model

BACKGROUND

Previous studies have shown that patients with pre-existing chronic obstructive pulmonary diseases (COPD) were more likely to be infected with coronavirus disease (COVID-19) and lead to more severe lung lesions. However, few studies have explored the severity and prognosis of COVID-19 patients with different phenotypes of COPD.

PURPOSE

The aim of this study is to investigate the value of the deep learning and radiomics features for the severity evaluation and the nucleic acid turning-negative time prediction in COVID-19 patients with COPD including two phenotypes of chronic bronchitis predominant patients and emphysema predominant patients.

METHODS

A total of 281 patients were retrospectively collected from Hohhot First Hospital between October 2022 and January 2023. They were divided to three groups: COVID-19 group of 95 patients, COVID-19 with emphysema group of 94 patients, COVID-19 with chronic bronchitis group of 92 patients. All patients underwent chest computed tomography (CT) scans and recorded clinical data. The U-net model was pretrained to segment the pulmonary involvement area on CT images and the severity of pneumonia were evaluated by the percentage of pulmonary involvement volume to lung volume. The 107 radiomics features were extracted by pyradiomics package. The Spearman method was employed to analyze the correlation of the data and visualize it through a heatmap. Then we establish a deep learning model (model 1) and a fusion model (model 2) combined deep learning with radiomics features to predict nucleic acid turning-negative time.

RESULTS

COVID-19 patients with emphysema was lowest in the lymphocyte count compared to COVID-19 patients and COVID-19 companied with chronic bronchitis, and they have the most extensive range of pulmonary inflammation. The lymphocyte count was significantly correlated with pulmonary involvement and the time for nucleic acid turning negative (r=-0.145, P < 0.05). Importantly, our results demonstrated that model 2 achieved an accuracy of 80.9% in predicting nucleic acid turning-negative time.

CONCLUSION

The pre-existing emphysema phenotype of COPD severely aggravated the pulmonary involvement of COVID-19 patients. Deep learning and radiomics features may provide more information to accurately predict the nucleic acid turning-negative time, which is expected to play an important role in clinical practice.

Identification and evaluation of candidate COVID-19 critical genes and medicinal drugs related to plasma cells

The ongoing COVID-19 pandemic, caused by the SARS-CoV-2 virus, represents one of the most significant global health crises in recent history. Despite extensive research into the immune mechanisms and therapeutic options for COVID-19, there remains a paucity of studies focusing on plasma cells. In this study, we utilized the DESeq2 package to identify differentially expressed genes (DEGs) between COVID-19 patients and controls using datasets GSE157103 and GSE152641. We employed the xCell algorithm to perform immune infiltration analyses, revealing notably elevated levels of plasma cells in COVID-19 patients compared to healthy individuals. Subsequently, we applied the Weighted Gene Co-expression Network Analysis (WGCNA) algorithm to identify COVID-19 related plasma cell module genes. Further, positive cluster biomarker genes for plasma cells were extracted from single-cell RNA sequencing data (GSE171524), leading to the identification of 122 shared genes implicated in critical biological processes such as cell cycle regulation and viral infection pathways. We constructed a robust protein-protein interaction (PPI) network comprising 89 genes using Cytoscape, and identified 20 hub genes through cytoHubba. These genes were validated in external datasets (GSE152418 and GSE179627). Additionally, we identified three potential small molecules (GSK-1070916, BRD-K89997465, and idarubicin) that target key hub genes in the network, suggesting a novel therapeutic approach. These compounds were characterized by their ability to down-regulate AURKB, KIF11, and TOP2A effectively, as evidenced by their low free binding energies determined through computational analyses using cMAP and AutoDock. This study marks the first comprehensive exploration of plasma cells' role in COVID-19, offering new insights and potential therapeutic targets. It underscores the importance of a systematic approach to understanding and treating COVID-19, expanding the current body of knowledge and providing a foundation for future research.

T Lymphocyte Characteristic Changes Under Serum Cytokine Deviations and Prognostic Factors of COVID-19 in Pregnant Women

Physiological changes during pregnancy make the individuals more susceptible to severe respiratory diseases. Hence, pregnant women with coronavirus disease 2019 (COVID-19) are likely at a higher risk. We investigated the effects of COVID-19 on T cell response and serum cytokine profile in pregnant patients. Peripheral blood mononuclear cells (PBMCs) of women with COVID-19 were collected during the first trimester of pregnancy, and the percentage of total lymphocytes, as well as CD4 + and CD8 + T cells, was assessed using flow cytometry. The expression of the programmed death-1 (PD-1) marker for exhausted T cells was evaluated. Additionally, the serum samples were provided to evaluate the levels of antiviral and proinflammatory cytokines, as well as laboratory serological tests. Pregnant women with COVID-19 presented lymphopenia with diminished CD4 + and CD8 + T cells. Besides, high expression levels of the PD-1 gene and protein were observed on PBMCs and T cells, respectively, when compared with normal pregnant individuals. Moreover, serum levels of TNF-α, IL-6, IL-1β, and IL-2 receptor were notably enhanced, while IFN-I α/β values were significantly decreased in the patients when compared with controls. Furthermore, hyperlipidemia, hyperglycemia, and hypertension were directly correlated with the disease although serum albumin and vitamin D3 levels adversely affected the viral infection. Our study showed extreme lymphopenia and poor T cell response while elevated values of serum inflammatory cytokines in infected pregnant women. Moreover, a hypertension background or metabolic changes, including hyperlipidemia, hyperglycemia, and vitamin D3 or albumin deficiency, might be promising prognostic factors in pregnant women with COVID-19.

COVID-19 vaccination in cancer patients: Immune responses one year after the third dose

Cancer patients (CPs), being immunosuppressed due to the treatment received or to the disease itself, are more susceptible to infections and their potential complications, showing therefore an increased risk of developing severe COVID-19 compared to the general population. We evaluated the immune responses to anti-SARS-CoV-2 vaccination in patients with solid tumors one year after the administration of the third dose and the effect of cancer treatment on vaccine immunogenicity was assessed. Healthy donors (HDs) were enrolled. Binding and neutralizing antibody (Ab) titers were evaluated using chemiluminescence immunoassay (CLIA) and Plaque Reduction Neutralization Test (PRNT) respectively. T-cell response was analyzed using multiparametric flow cytometry. CPs who were administered three vaccine doses showed lower Ab titers than CPs with four doses and HDs. Overall, a lower cell-mediated response was found in CPs, with a predominance of monofunctional T-cells producing TNFα. Lower Ab titers and a weaker T-cell response were observed in CPs without prior SARS-CoV-2 infection when compared to those with a previous infection. While no differences in the humoral response were found comparing immunotherapy and non-immunotherapy patients, a stronger T-cell response in CPs treated with immunotherapy was observed. Our results emphasize the need of booster doses in cancer patients to achieve a level of protection similar to that observed in healthy donors and underlines the importance of considering the treatment received to reach a proper immune response.

Evaluation of changes in exhausted T lymphocytes and miRNAs expression in the different trimesters of pregnancy in pregnant women

BACKGROUND

Throughout the three trimesters of a typical pregnancy, we looked at changes in the expression of miRNAs and exhausted T lymphocytes for this study.

METHODS AND RESULTS

Fifty healthy subjects were included in this study. The frequency of exhausted T lymphocytes was measured in isolated PBMCs using flow cytometry. PD-1, TIM-3, and related miRNAs gene expression were assessed using qRT-PCR. The analyses revealed a significant decline in PD-1 and Tim-3 expression in PBMCs from RPL women (p = 0.0003 and p = 0.001, respectively). In addition, PD-1 and TIM-3 expression increased significantly in the 2nd trimester compared with the 1st trimester of healthy pregnant women (p < 0.0001 and p = 0.0002, respectively). PD-1 and TIM-3 expression was down-regulated in the 3rd trimester compared with the 1st and 2nd trimesters. In the present study, we demonstrated that TIM-3+/CD4+, TIM-3+/CD8+, PD-1+/CD4+, and PD-1+/CD8 + exhausted T lymphocytes increased in the circulation of women in the 2nd trimester compared to the 1st and 3rd trimester. In the 3rd trimester, the expression of miR-16-5p increased significantly (p < 0.0001). miR-125a-3p expression was down and upregulated in 2nd (p < 0.0001) and 3rd (p = 0.0007) trimesters compared to 1st trimester, respectively. This study showed a significant elevation of miR-15a-5p in 3rd trimester compared to 1st trimester of pregnant women (p = 0.0002).

CONCLUSIONS

Expression pattern of PD-1 and TIM3 in exhausted T lymphocytes is different not only between normal pregnant and RPL women but also in different trimesters of pregnancy. So, our results showed the role of these markers in the modulation lymphocytes activity in different stages of pregnancy.

Integrative single-cell analysis: dissecting CD8 + memory cell roles in LUAD and COVID-19 via eQTLs and Mendelian Randomization

Lung adenocarcinoma exhibits high incidence and mortality rates, presenting a significant health concern. Concurrently, the COVID-19 pandemic has emerged as a grave global public health challenge. Existing literature suggests that T cells, pivotal components of cellular immunity, are integral to both antiviral and antitumor responses. Yet, the nuanced alterations and consequent functions of T cells across diverse disease states have not been comprehensively elucidated. We gathered transcriptomic data of peripheral blood mononuclear cells from lung adenocarcinoma patients, COVID-19 patients, and healthy controls. We followed a standardized analytical approach for quality assurance, batch effect adjustments, and preliminary data processing. We discerned distinct T cell subsets and conducted differential gene expression analysis. Potential key genes and pathways were inferred from GO and Pathway enrichment analyses. Additionally, we implemented Mendelian randomization to probe the potential links between pivotal genes and lung adenocarcinoma susceptibility. Our findings underscored a notable reduction in mature CD8 + central memory T cells in both lung adenocarcinoma and COVID-19 cohorts relative to the control group. Notably, the downregulation of specific genes, such as TRGV9, could impede the immunological efficacy of CD8 + T cells. Comprehensive multi-omics assessment highlighted genetic aberrations in genes, including TRGV9, correlating with heightened lung adenocarcinoma risk. Through rigorous single-cell transcriptomic analyses, this investigation meticulously delineated variations in T cell subsets across different pathological states and extrapolated key regulatory genes via an integrated multi-omics approach, establishing a robust groundwork for future functional inquiries. This study furnishes valuable perspectives into the etiology of multifaceted diseases and augments the progression of precision medicine.

Prevalence of indeterminate tuberculosis interferon-gamma release assays in COVID-19 patients: Systematic review and meta-analysis

Background and Aims

The reliability of interferon-gamma-release-assays (IGRAs) for tuberculosis (TB) testing in coronavirus disease 2019 (COVID-19) patients is unknown. This study aimed to systematically review the prevalence of indeterminate TB-IGRA following SARS-CoV-2 infection or vaccination and to review associated factors.

Methods

This systematic literature review was guided according to the PRISMA guidelines by searching PubMed, Scopus, Web of Science, Clinicalkey, and Cochrane Library. Studies reporting results of TB-IGRA tests (QuantiFERON [QFT]-TB, T-SPOT.TB) in COVID-19 patients or vaccines were included. The random effects model was used to assess the prevalence of indeterminate IGRA results. Heterogeneity was evaluated using the Τ 2 and 95% predictive interval.

Results

Of the 273 citations screened, 12 articles were included in the final analysis including a total of 2107 patients. The overall pooled effect size proportion of indeterminate QFT-TB results, estimated in eight studies using the QFT-TB Plus assay, was 0.26 (95% CI: 0.205-0.324, Τ 2 = 0.158). The mean true effect size was 0.26 (95% predictive interval: [0.110-0.500]). A subgroup analysis was not undertaken due to the small number of studies. Indeterminate QFT-TB rates were associated with COVID-19 severity, steroid treatment, inflammation-related parameters, neutrophilia, and lymphopenia.

Conclusion

Indeterminate QFT-TB results in COVID-19 patients occur in almost one-quarter of tests performed. Further studies are needed to assess associated factors.

The kinetics of inhibitory immune checkpoints during and post-COVID-19: the knowns and unknowns

The immune system is tightly regulated to prevent immune reactions to self-antigens and to avoid excessive immune responses during and after challenges from non-self-antigens. Inhibitory immune checkpoints (IICPs), as the major regulators of immune system responses, are extremely important for maintaining the homeostasis of cells and tissues. However, the high and sustained co-expression of IICPs in chronic infections, under persistent antigenic stimulations, results in reduced immune cell functioning and more severe and prolonged disease complications. Furthermore, IICPs-mediated interactions can be hijacked by pathogens in order to evade immune induction or effector mechanisms. Therefore, IICPs can be potential targets for the prognosis and treatment of chronic infectious diseases. This is especially the case with regards to the most challenging infectious disease of recent times, coronavirus disease-2019 (COVID-19), whose long-term complications can persist long after recovery. This article reviews the current knowledge about the kinetics and functioning of the IICPs during and post-COVID-19.

Combining nano-curcumin with catechin improves COVID-19-infected patient's inflammatory conditions

AIMS

A hyperinflammatory condition is brought on by the development of Coronavirus disease 2019 (COVID-19), which is characterized by an elevation of T helper (Th) 17 cells, high levels of pro-inflammatory cytokines, and a depletion of regulatory T (Treg) cells.

METHODS

In this research, we examined the effect of nano-curcumin and catechin on the TCD4+, TCD8+, Th17, and Treg cells and their associated factors in COVID-19 patients. For this purpose, 160 (50 patients excluded during the study) COVID-19 patients were divided into four groups: placebo, nano-curcumin, catechin, and nano-curcumin + catechin. The frequency of TCD4+, TCD8+, Th17, and Treg cells, the gene expression of transcription factors (STAT3, RORt, and FoxP3) relevant to Th17 and Treg, as well as the serum levels of cytokines (IL-6, IL17, IL1-b, IL-10, and TGF-), were all evaluated intra- and inter-group, before and after treatment, in all groups.

RESULTS

Our study showed that TCD4 + and TCD8 + cells were significantly higher in the nano-curcumin + catechin group compared to the control group, whereas Th17 was lower than the initial value. Furthermore, compared to the placebo-received group, cytokines and transcription factors associated with Th17 were significantly lower in the nano-curcumin + catechin group. Additionally, combined therapy increased Treg cells and transcription factors compared to the placebo group.

CONCLUSION

Overall, our results show that combining nano-curcumin with catechin has a more notable impact on the enhancement of TCD4+, TCD8+, and Treg cells, as well as a decrease in Th17 cells and their mediators, suggesting a promising combination therapy in reducing the inflammatory conditions of COVID-19 infected patients.

SARS-CoV2 infection induce miR-155 expression and skewed Th17/Treg balance by changing SOCS1 level: A clinical study

BACKGROUND

One of the regulators in severe acute respiratory syndrome coronavirus2 (SARS-CoV2) infection is miRNAs. In COVID-19 patients, immunological responses to SARS-CoV2 infection may be impacted by miR-155, a miRNA associated to inflammation.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) of 50 confirmed COVID-19 patients /Healthy Controls (HCs) was isolated by Ficoll. The frequency of T helper 17 and regulatory T cells was analyzed by flowcytometry. The RNA was extracted from each sample and after synthesis of c-DNA, the relative expression of miR-155, suppressor of cytokine signaling (SOCS-1), Signal transducer and activator of transcription 3(STAT3), and Fork Head Box Protein 3 (FoxP3) was evaluated by real-time PCR. The protein level of STAT3, FoxP3 and RORγT in the isolated PBMCs measured by western blotting. The serum level of IL-10, TGF-β, IL-17 and IL21 was assessed by ELISA method.

RESULTS

The population of Th17 cells showed a significant rise, whereas Treg cells reduced in COVID-19 cases. The master transcription factor of Treg (FoxP3) and Th17 (RORγT) relative expression showed the same pattern as flowcytometry. STAT3 level of expression at RNA and protein level increased in COVID-19 cases. FOXP3 and SOCS-1 proteins were down-regulated. The relative expression of miR-155, up-regulated in PBMC of COVID-19 patients and revealed a negative correlation with SOCS-1. The serum cytokine profile showed a reduction in TGF-β, on the other hand an increase was seen in IL-17, IL-21 and IL-10 in COVID-19 cases toward control group.

CONCLUSION

Based on the studies conducted in this field, it can be suggested that Th17/Treg in covid-19 patients can be affected by miR-155 and it can be considered a valuable diagnostic and prognostic factor in this disease.

Epithelial Galectin-3 Induced the Mitochondrial Complex Inhibition and Cell Cycle Arrest of CD8+ T Cells in Severe/Critical COVID-19

Previous research suggested that the dramatical decrease in CD8+ T cells is a contributing factor in the poor prognosis and disease progression of COVID-19 patients. However, the underlying mechanisms are not fully understood. In this study, we conducted Single-cell RNA sequencing (scRNA-seq) and single-cell T cell receptor sequencing (scTCR-seq) analysis, which revealed a proliferative-exhausted MCM+FASLGlow CD8+ T cell phenotype in severe/critical COVID-19 patients. These CD8+ T cells were characterized by G2/M cell cycle arrest, downregulation of respiratory chain complex genes, and inhibition of mitochondrial biogenesis. CellChat analysis of infected lung epithelial cells and CD8+ T cells found that the galectin signaling pathway played a crucial role in CD8+ T cell reduction and dysfunction. To further elucidate the mechanisms, we established SARS-CoV-2 ORF3a-transfected A549 cells, and co-cultured them with CD8+ T cells for ex vivo experiments. Our results showed that epithelial galectin-3 inhibited the transcription of the mitochondrial respiratory chain complex III/IV genes of CD8+ T cells by suppressing the nuclear translocation of nuclear respiratory factor 1 (NRF1). Further findings showed that the suppression of NRF1 translocation was associated with ERK-related and Akt-related signaling pathways. Importantly, the galectin-3 inhibitor, TD-139, promoted nuclear translocation of NRF1, thus enhancing the expression of the mitochondrial respiratory chain complex III/IV genes and the mitochondrial biogenesis of CD8+ T cells. Our study provided new insights into the immunopathogenesis of COVID-19 and identified potential therapeutic targets for the prevention and treatment of severe/critical COVID-19 patients.

Oxygen Requirement in Overweight/Obese Kidney Transplant Recipients with COVID-19: An Observational Cohort Study

INTRODUCTION

Obesity is one of the components of the cardiometabolic syndrome that contributes to COVID-19 progression and mortality. Immunosuppressed individuals are at greater risk of the COVID-19 burden. Therefore, we sought to investigate the impact of the combination of overweight/obesity and kidney transplant on oxygen (O2) requirements in the COVID-19 setting.

METHODS

Retrospective analysis of 284 kidney transplant recipients (KTRs) from March/2020 to August/2020 in a single center. We investigated the risk factors associated with O2 requirements in overweight/obese KTRs.

RESULTS

Overall, 65.1% had a BMI (body mass index) ≥ 25 kg/m2, 52.4% were male, the mean age was 53.3 ± 11 years old, 78.4% had hypertension, and 41.1% had diabetes mellitus. BMI was an independent risk factor for O2 requirements (OR = 1.07, p = 0.02) alongside age, lymphopenia, and hyponatremia. When overweight/obese KTRs were older, smokers, they presented higher levels of lactate dehydrogenase (LDH), and lower levels of estimated glomerular filtration rate (eGFR), lymphocytes, and sodium at admission, and they needed O2 more often.

CONCLUSION

Being overweight/obese is associated with greater O2 requirements in KTRs, in particular in older people and smokers, with worse kidney allograft functions, more inflammation, and lower sodium levels. Therefore, the early identification of factors that predict a worse outcome in overweight/obese KTRs affected by COVID-19 contributes to risk stratification and therapeutic decisions.

Immune Dynamics Involved in Acute and Convalescent COVID-19 Patients

COVID-19 is a viral disease that has caused millions of deaths around the world since 2020. Many strategies have been developed to manage patients in critical conditions; however, comprehension of the immune system is a key factor in viral clearance, tissue repairment, and adaptive immunity stimulus. Participation of immunity has been identified as a major factor, along with biomarkers, prediction of clinical outcomes, and antibody production after infection. Immune cells have been proposed not only as a hallmark of severity, but also as a predictor of clinical outcomes, while dynamics of inflammatory molecules can also induce worse consequences for acute patients. For convalescent patients, mild disease was related to higher antibody production, although the factors related to the specific antibodies based on a diversity of antigens were not clear. COVID-19 was explored over time; however, the study of immunological predictors of outcomes is still lacking discussion, especially in convalescent patients. Here, we propose a review using previously published studies to identify immunological markers of COVID-19 outcomes and their relation to antibody production to further contribute to the clinical and laboratorial management of patients.

Potent SARS-CoV2-specific T-cell response in asymptomatic hemodialysis patients with hidden COVID-19 infection history

BACKGROUND

COVID-19-related immune responses in patients with end-stage renal disease (ESRD) are characterized in detail by the humoral response, but their cellular immunity has not been clarified. Here, we evaluated virus-specific T cells in parallel with serology-related tests.

METHODS

In this study, 104 ESRD patients at the hemodialysis ward of Imam Reza hospital at Tabriz (Iran) were enrolled. After blood sampling, SARS-CoV2-specific humoral and cellular immune responses were evaluated by SARS-CoV2-specific IgM/IgG ELISA and peptide/MHCI-Tetramers flow cytometry, respectively.

RESULTS

Our results showed that 14 (13.5%) and 45 (43.3%) patients had specific SARS-CoV2 IgM and IgG in their sera, respectively. Immunophenotyping for SARS-CoV2-specific CD8+ T lymphocytes revealed that 68 (65.4%) patients had these types of cells. Among SARS-CoV2-specific CD8+ T lymphocytes positive subjects, 13 and 43 individuals had positive results for specific SARS-CoV2 IgM and IgG existence, respectively. Also, there was a relationship between specific SARS-CoV2 IgM (p = 0.031) and IgG (p < 0.0001) existence and having SARS-CoV2-specific TCD8+ lymphocytes in the studied population.

CONCLUSION

Despite not having clinical symptoms, a high rate of SARS-CoV2-specific T-cell response in asymptomatic ESRD patients may reveal a high burden of asymptomatic COVID-19 infection in these patients.

Encephalic nocardiosis after mild COVID-19: A case report

The COVID-19 pandemic and the associated post-acute sequelae of COVID-19 (PASC) have led to the identification of a complex disease phenotype that is associated with important changes in the immune system. Herein, we describe a unique case of Nocardia farcinica cerebral abscess in an individual with sudden immunodeficiency several months after mild COVID-19. Intravenous Bactrim and Imipenem were prescribed for 6 weeks. After this, a 12-month course of Bactrim and Clavulin was prescribed to be taken orally, given the N. farcinica infection at the level of the central nervous system. This case report highlights the need for future research into the pathophysiology of COVID-19 and PASC immune dysregulation in convalescent individuals. It also draws attention to the need for timely consideration of opportunistic infections in patients with a history of COVID-19.

Adaptive immune system in severe COVID-19 patients in the first week of illness: A pilot study

Introduction

The presentation of the course of COVID-19-related T-cell responses in the first week of the disease may be a more specific period for adaptive immune response assessment. This study aimed to clarify the relationship between changes in peripheral blood lymphocyte counts and death in patients with COVID-19 pneumonia.

Methods

Thirty-three patients (14 females and 19 males) admitted for severe and desaturated COVID-19 pneumonia confirmed by polymerase chain reaction were included. Lymphocyte subsets and CD4+/CD8+ and CD16+/CD56+ rates were measured using flow cytometry from peripheral blood at admission and on the day of death or hospital discharge.

Results

Twenty-eight patients survived and five died. On the day of admission, the CD4+ cell count was significantly higher and the saturation of O2 was significantly lower in the deceased patients compared to the survivors (P < 0.05). The CD16+/CD56+ rate was significantly lower on the day of death in the deceased patients than in discharge day for the survivors (P = 0.013).

Conclusion

CD4+ lymphocyte percentages and O2 saturation in samples taken on the day of admission to the hospital and CD16+/CD56+ ratios taken at the time of discharge from the hospital were found to be associated with the mortality in patients with severe COVID-19.

Evidence of exhausted lymphocytes after the third anti-SARS-CoV-2 vaccine dose in cancer patients

Introduction

Evidence is scant regarding the long-term humoral and cellular responses Q7 triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in cancer patients after repeated booster doses. The possibility of T-cell exhaustion following these booster doses in this population has not yet been fully studied and remains uncertain.

Methods

In this single-center prospective observational study, we explored the specific humoral and cellular response to S1 antigen in 36 patients with solid malignancies at baseline, and after the second and third doses of the mRNA-1273 vaccine.

Results

A dual behavior was observed: 24 (66.7%) patients showed partial specific IFN-γ response after the second dose that was further enhanced after the third dose; and 11 (30.5%) already showed an optimal response after the second dose and experienced a marked fall-off of specific IFN-γ production after the third (4 patients negativization), which might suggest T cell exhaustion due to repetitive priming to the same antigen. One (2.8%) patient had persistently negative responses after all three doses. Seroconversion occurred in all patients after the second dose. We then studied circulating exhausted CD8+ T-cells in 4 patients from each of the two response patterns, those with increase and those with decrease in cellular response after the third booster. The patients with decreased cellular response after the booster had a higher expression of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells compared with those with an increased cellular response both in vivo and in vitro. The proportion of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells inversely correlated with IFN-γ production.

Discussion

Our preliminary data show that the two-dose SARS-CoV-2 vaccine regimen was beneficial in all cancer patients of our study. An additional booster seems to be beneficial in suboptimal vaccine seroconverters, in contrast to maximal responders that might develop exhaustion. Our data should be interpreted with caution given the small sample size and highlight the urgent need to validate our results in other independent and larger cohorts. Altogether, our data support the relevance of immunological functional studies to personalize preventive and treatment decisions in cancer patients.

The impact of Hyssop (Hyssopus officinalis) extract on activation of endosomal toll like receptors and their downstream signaling pathways

OBJECTIVES

From the ancient, medicinal benefits of Hyssop (Hyssopus officinalis L.) have been implicated for respiratory and digestive diseases despite the effects of Hyssop on viral infections have not been mechanistically investigated. In this study, we examined whether the Hyssop extract activated anti-viral innate immunity, as a sentinel for immune system, through activation of endosomal TLRs recognizing nucleic acids and their downstream signaling. The Hyssop herb extracts was prepared and co-cultured with healthy individual's peripheral blood mononuclear cells (PBMCs). After viability assay, gene expression levels of TLR3,7,8,9, as well as MyD88 and NF-κB, were evaluated in treated PBMCs using Real-time PCR. Next, the secretion level of immune related cytokines was quantified via ELISA.

RESULTS

Post 24 h, 40 µg/ml of the extract significantly inhibited the viability of less than 50% of cells compared to the control and had a maximum effect on cellular function. The Hyssop-treated PBMCs demonstrated an elevated expression of endosomal TLRs genes, as well as MyD88 and NF-κB. Moreover, the release of INF-α and β notably enhanced in cell culture supernatant, while the content of inflammatory cytokines remarkably diminished (P < 0.05). The Hyssop extract was capable of inducing antiviral innate immune responses so can be promising in antiviral drug strategies.

Immune checkpoint alterations and their blockade in COVID-19 patients

Coronavirus disease 2019 (COVID-19) is a highly contagious disease that seriously affects people's lives. Immune dysfunction, which is characterized by abnormal expression of multiple immune checkpoint proteins (ICs) on immune cells, is associated with progression and poor prognosis for tumors and chronic infections. Immunotherapy targeting ICs has been well established in modulating immune function and improving clinical outcome for solid tumors and hematological malignancies. The role of ICs in different populations or COVID-19 stages and the impact of IC blockade remains unclear. In this review, we summarized current studies of alterations in ICs in COVID-19 to better understand immune changes and provide strategies for treating COVID-19 patients, particularly those with cancer.

Immune system-related soluble mediators and COVID-19: basic mechanisms and clinical perspectives

During SARS-CoV-2 infection, an effective immune response provides the first line of defense; however, excessive inflammatory innate immunity and impaired adaptive immunity may harm tissues. Soluble immune mediators are involved in the dynamic interaction of ligands with membrane-bound receptors to maintain and restore health after pathological events. In some cases, the dysregulation of their expression can lead to disease pathology. In this literature review, we described current knowledge of the basic features of soluble immune mediators and their dysregulation during SARS-CoV-2 infections and highlighted their contribution to disease severity and mortality.

Expression level of immune checkpoint inhibitory factors in preeclampsia

Preeclampsia (PE) is a severe complication in pregnancy, and its symptoms (proteinuria and hypertension) manifest after 20 weeks of gestation, affecting up to 8 % of pregnancies. The pregnant women's immune system uses different tolerance mechanisms to deal with a semi-allogeneic fetus. The T-cell subsets including CD8+, CD4+, and Treg play a critical role in maintaining pregnancies. The expression of immune checkpoint molecules in T-cells can ensure pregnancy at the feto-maternal interface by controlling immune responses. This research aims to evaluate the expression level of immune checkpoint factors, including PD-1, LAG-3, CTLA-4, and TIM-3 in normal pregnant women and PE patients. Decidual tissue was collected from 50 participants (25 PE and 25 control). For evaluating the genes expression, real-time PCR was employed. The western blot was used to assess the proteins level. The results of real-time PCR indicated significantly decreased expression level of these immune checkpoints in PE patients. In parallel to gene expression results, the protein level of PD-1, LAG-3, CTLA-4, and TIM-3 in the PE group was also reduced. We revealed that the profile of proteins and genes expression of immune checkpoints in the decidua of PE mothers are different from normal pregnancy and these results indicate aberrant expression of immune checkpoints such as PD-1, LAG-3, CTLA-4, and TIM-3 may cause maladaptation immune response which results in PE manifestation.

A comprehensive evaluation of the immune system response and type-I Interferon signaling pathway in hospitalized COVID-19 patients

BACKGROUND

The COVID-19 pandemic has become the world's main life-threatening challenge in the third decade of the twenty-first century. Numerous studies have been conducted on SARS-CoV2 virus structure and pathogenesis to find reliable treatments and vaccines. The present study aimed to evaluate the immune-phenotype and IFN-I signaling pathways of COVID-19 patients with mild and severe conditions.

MATERIAL AND METHODS

A total of 100 COVID-19 patients (50 with mild and 50 with severe conditions) were enrolled in this study. The frequency of CD4 + T, CD8 + T, Th17, Treg, and B lymphocytes beside NK cells was evaluated using flow cytometry. IFN-I downstream signaling molecules, including JAK-1, TYK-2, STAT-1, and STAT-2, and Interferon regulatory factors (IRF) 3 and 7 expressions at RNA and protein status were investigated using real-time PCR and western blotting techniques, respectively. Immune levels of cytokines (e.g., IL-1β, IL-6, IL-17, TNF-α, IL-2R, IL-10, IFN-α, and IFN-β) and the existence of anti-IFN-α autoantibodies were evaluated via enzyme-linked immunosorbent assay (ELISA).

RESULTS

Immune-phenotyping results showed a significant decrease in the absolute count of NK cells, CD4 + T, CD8 + T, and B lymphocytes in COVID-19 patients. The frequency of Th17 and Treg cells showed a remarkable increase and decrease, respectively. All signaling molecules of the IFN-I downstream pathway and IRFs (i.e., JAK-1, TYK-2, STAT-1, STAT-2, IRF-3, and IRF-7) showed very reduced expression levels in COVID-19 patients with the severe condition compared to healthy individuals at both RNA and protein levels. Of 50 patients with severe conditions, 14 had anti-IFN-α autoantibodies in sera. Meanwhile, this result was 2 and 0 for patients with mild symptoms and healthy controls, respectively.

CONCLUSION

Our results indicate a positive association of the existence of anti-IFN-α autoantibodies and immune cells dysregulation with the severity of illness in COVID-19 patients. However, comprehensive studies are necessary to find out more about this context. Video abstract.

Immune Senescence, Immunosenescence and Aging

With aging, there is increased dysfunction of both innate and adaptive immune responses, which contributes to impaired immune responses to pathogens and greater mortality and morbidity. This age-related immune dysfunction is defined in general as immunosenescence and includes an increase in the number of memory T cells, loss of ability to respond to antigen and a lingering level of low-grade inflammation. However, certain features of immunosenescence are similar to cellular senescence, which is defined as the irreversible loss of proliferation in response to damage and stress. Importantly, senescence cells can develop an inflammatory senescence-associated secretory phenotype (SASP), that also drives non-autonomous cellular senescence and immune dysfunction. Interestingly, viral infection can increase the extent of immune senescence both directly and indirectly, leading to increased immune dysfunction and inflammation, especially in the elderly. This review focuses on age-related immune dysfunction, cellular senescence and the impaired immune response to pathogens.

Serum levels of vitamin D and immune system function in patients with COVID-19 admitted to intensive care unit

Objective

Vitamin D is believed to affect the functionality of the immune system for the prevention of coronavirus disease. To investigate the role of this vitamin against the Coronavirus, this study analyzed the serum levels of vitamin D, the transcription pattern of inflammatory cytokines, and the frequency of total lymphocytes, TCD4⁺, TCD8⁺, and NK cells in 50 COVID-19-affected subjects in comparison to 50 healthy participants.

Materials and methods

This study diagnosed and evaluated 100 patients. Frequency of lymphocytes was determined using flow cytometry. Cytokine expression levels were measured using Real-Time PCR. Serum levels of vitamin D and cytokines levels in cultured cell supernatant were measured by ELISA.

Results

Patients with COVID-19 exhibited decreased serum levels of vitamin D versus the healthy participants (p = 0.0024). The total number of lymphocytes, TCD4⁺, TCD8⁺, and NK cells was significantly reduced in patients with COVID-19 (p < 0.0001). Considerable upregulation of IL-12, IFN-γ, and TNF-α was seen in COVID-19 patients compared to the control group, whereas IFN-α was downregulated in COVID-19 patients. ELISA results also had increased levels of IL-12, TNF-α, and IFN-γ (p = 0.0014, 0.0012, and p < 0.0001, respectively), and decreased level of IFN-α (p = 0.0021) in patients with COVID-19 compared to the control group.

Conclusion

These findings suggest a probable association among vitamin D concentrations, immune system function, and risk of COVID-19 infection. As a result, it is recommended that vitamin D be considered as a candidate for handling and controlling COVID-19 because of its ability to target the cytokine storm and its antiviral effects.

Evaluation of the Potential Risk of Mortality from SARS-CoV-2 Infection in Hospitalized Patients According to the Charlson Comorbidity Index

Background: The pandemic of COVID-19 has represented a major threat to global public health in the last century and therefore to identify predictors of mortality among COVID-19 hospitalized patients is widely justified. The aim of this study was to evaluate the possible usefulness of Charlson Comorbidity Index (CCI) as mortality predictor in patients hospitalized because COVID-19. Methods: This study was carried out in Zacatecas, Mexico, and it included 705 hospitalized patients with suspected of SARS-CoV-2 infection. Clinical data were collected, and the CCI score was calculated online using the calculator from the Sociedad Andaluza de Medicina Intensiva y Unidades Coronarias; the result was evaluated as mortality predictor among the patients with COVID-19. Results: 377 patients were positive for SARS-COV-2. Obesity increased the risk of intubation among the study population (odds ratio (OR) = 2.59; 95 CI: 1.36–4.92; p = 0.003). The CCI values were higher in patients who died because of COVID-19 complications than those observed in patients who survived (p < 0.001). Considering a CCI cutoff > 31.69, the area under the ROC curve was 0.75, with a sensitivity and a specificity of 63.6% and 87.7%, respectively. Having a CCI value > 31.69 increased the odds of death by 12.5 times among the study population (95% CI: 7.3–21.4; p < 0.001). Conclusions: The CCI is a suitable tool for the prediction of mortality in patients hospitalized for COVID-19. The presence of comorbidities in hospitalized patients with COVID-19 reflected as CCI > 31.69 increased the risk of death among the study population, so it is important to take precautionary measures in patients due to their condition and their increased vulnerability to SARS-CoV-2 infection.

Nocardiosis of the Central Nervous System: A rare complication of COVID management?

This case report examines a previously immunocompetent male that was treated with a prolonged course of corticosteroids for COVID pneumonia. He then returned with worsening headaches followed by flaccid paralysis of extremities due to cerebral and spinal cord abscesses secondary to Nocardia farcinica. A review of the literature on the mechanism of immunosuppression with COVID infection and corticosteroids is provided.