Dynamic changes in lymphocyte subsets and parallel cytokine levels in patients with severe and critical COVID-19

Host Response Changes and Their Association with Mortality in COVID-19 Patients with Lymphopenia

Rationale: Lymphopenia in coronavirus disease (COVID-19) is associated with increased mortality. Objectives: To explore the association between lymphopenia, host response aberrations, and mortality in patients with lymphopenic COVID-19. Methods: We determined 43 plasma biomarkers reflective of four pathophysiological domains: endothelial cell and coagulation activation, inflammation and organ damage, cytokine release, and chemokine release. We explored if decreased concentrations of lymphocyte-derived proteins in patients with lymphopenia were associated with an increase in mortality. We sought to identify host response phenotypes in patients with lymphopenia by cluster analysis of plasma biomarkers. Measurements and Main Results: A total of 439 general ward patients with COVID-19 were stratified by baseline lymphocyte counts: normal (>1.0 × 109/L; n = 167), mild lymphopenia (>0.5 to ⩽1.0 × 109/L; n = 194), and severe lymphopenia (⩽0.5 × 109/L; n = 78). Lymphopenia was associated with alterations in each host response domain. Lymphopenia was associated with increased mortality. Moreover, in patients with lymphopenia (n = 272), decreased concentrations of several lymphocyte-derived proteins (e.g., CCL5, IL-4, IL-13, IL-17A) were associated with an increase in mortality (at P < 0.01 or stronger significance levels). A cluster analysis revealed three host response phenotypes in patients with lymphopenia: "hyporesponsive" (23.2%), "hypercytokinemic" (36.4%), and "inflammatory-injurious" (40.4%), with substantially differing mortality rates of 9.5%, 5.1%, and 26.4%, respectively. A 10-biomarker model accurately predicted these host response phenotypes in an external cohort with similar mortality distribution. The inflammatory-injurious phenotype showed a remarkable combination of relatively high inflammation and organ damage markers with high antiinflammatory cytokine levels yet low proinflammatory cytokine levels. Conclusions: Lymphopenia in COVID-19 signifies a heterogenous group of patients with distinct host response features. Specific host responses contribute to lymphopenia-associated mortality in COVID-19, including reduced CCL5 levels.

Contrasting mechanistic susceptibilities of hematopoietic and endothelial stem-progenitor cells in respective pathogeneses of HIV-1 and SARS-CoV-2 infections

The multitude of cellular types can be expected to behave differently when receiving invading pathogens such as mammalian viruses. The nature-dictated causes for such intrinsic cellular diversity become the criteria for the emergence of specific virus-receptor interactions on that particular host cellular surface, in order to accommodate contact with various other living entities whether desirable to the host or not. At present, we are presented with an example of two contrasting behaviours wherein the well-known HIV-1 and the more recently emergent SARS-CoV-2 cause adverse consequences to the differentiation and functions of progenitor stem cells. These include the two different downstream multipotent CD34+ hematopoietic (HSPC) and CD133+ endothelial (ESPC) stem-progenitor cells of their common pluripotent hemangioblast precursors. The two viruses target the respective endothelial and hematopoietic stem-progenitor cells to thrive upon the relevant host cellular surrounded stromal microenvironments by adopting reciprocally-driven mechanistic routes, which incidentally cause pathogenesis either directly of ESPC (SARS-CoV-2), or indirectly of HSPC (HIV-1). HIV-1 utilizes the CD4+ T-lymphocyte receptor thereby advancing pathogenesis indirectly to the CD34+ HSPC. SARS-CoV-2 directly targets the CD133+ ESPC via ACE2 receptor causing cytokine storms of the CD4+ T-lymphocytes. In this manner, these two viruses cause and extend their damage to the other cellular sub/types coexisting in the host cellular microenvironments. The infected individuals require clinical interventions that are efficacious to prevent cellular dysfunction and ultimate cell depletion or death. We infer from these viruses mediated pathogeneses mechanisms a potential common origin of microRNA molecular therapies to address cellular dysfunctions and prevent cell loss.

Epigenetic perspectives associated with COVID-19 infection and related cytokine storm: an updated review

PURPOSE

The COVID-19 pandemic caused by the novel Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) has put the world in a medical crisis for the past three years; nearly 6.3 million lives have been diminished due to the virus outbreak. This review aims to update the recent findings on COVID-19 infections from an epigenetic scenario and develop future perspectives of epi-drugs to treat the disease.

METHODS

Original research articles and review studies related to COVID-19 were searched and analyzed from the Google Scholar/PubMed/Medline databases mainly between 2019 and 2022 to brief the recent work.

RESULTS

Numerous in-depth studies of the mechanisms used by SARS-CoV-2 have been going on to minimize the consequences of the viral outburst. Angiotensin-Converting Enzyme 2 receptors and Transmembrane serine protease 2 facilitate viral entry to the host cells. Upon internalization, it uses the host machinery to replicate viral copies and alter the downstream regulation of the normal cells, causing infection-related morbidities and mortalities. In addition, several epigenetic regulations such as DNA methylation, acetylation, histone modifications, microRNA, and other factors (age, sex, etc.) are responsible for the regulations of viral entry, its immune evasion, and cytokine responses also play a major modulatory role in COVID-19 severity, which has been discussed in detail in this review.

CONCLUSION

Findings of epigenetic regulation of viral pathogenicity open a new window for epi-drugs as a possible therapeutical approach against COVID-19.

Comparative analysis of clinical and immunological profiles across Omicron BA.5.2 subvariants using next-generation sequencing in a Chinese cohort

Objective

The Omicron BA.5.2 variant of SARS-CoV-2 has undergone several evolutionary adaptations, leading to multiple subvariants. Rapid and accurate characterization of these subvariants is essential for effective treatment, particularly in critically ill patients. This study leverages Next-Generation Sequencing (NGS) to elucidate the clinical and immunological features across different Omicron BA.5.2 subvariants.

Methods

We enrolled 28 patients infected with the Omicron variant, hospitalized in Zhangjiajie People's Hospital, Hunan, China, between January 20, 2023, and March 31, 2023. Throat swabs were collected upon admission for NGS-based identification of Omicron subvariants. Clinical data, including qSOFA scores and key laboratory tests, were collated. A detailed analysis of lymphocyte subsets was conducted to ascertain the extent of immune cell damage and disease severity.

Results

Patients were infected with various Omicron subvariants, including BA.5.2.48, BA.5.2.49, BA.5.2.6, BF.7.14, DY.1, DY.2, DY.3, and DY.4. Despite having 43 identical mutation sites, each subvariant exhibited unique marker mutations. Critically ill patients demonstrated significant depletion in total lymphocyte count, T cells, CD4, CD8, B cells, and NK cells (P < 0.05). However, there were no significant differences in clinical and immunological markers across the subvariants.

Conclusion

This study reveals that critically ill patients infected with different Omicron BA.5.2 subvariants experience similar levels of cellular immune dysfunction and inflammatory response. Four mutations - ORF1a:K3353R, ORF1a:L3667F, ORF1b:S997P, S:T883I showed correlation with immunological responses although this conclusion suffers from the small sample size. Our findings underscore the utility of NGS in the comprehensive assessment of infectious diseases, contributing to more effective clinical decision-making.

Vascular risk factors for COVID-19 ARDS: endothelium, contact-kinin system

SARS-CoV-2 binds to ACE2 receptors, expressed within the lungs. Risk factors for hospitalization include hypertension, diabetes, ischaemic heart disease and obesity-conditions linked by the presence of endothelial pathology. Viral infection in this setting causes increased conversion of circulating Factor XII to its active form (FXIIa). This is the first step in the contact-kinin pathway, leading to synchronous activation of the intrinsic coagulation cascade and the plasma Kallikrein-Kinin system, resulting in clotting and inflammatory lung disease. Temporal trends are evident from blood results of hospitalized patients. In the first week of symptoms the activated partial thromboplastin time (APTT) is prolonged. This can occur when clotting factors are consumed as part of the contact (intrinsic) pathway. Platelet counts initially fall, reflecting their consumption in coagulation. Lymphopenia occurs after approximately 1 week, reflecting the emergence of a lymphocytic pneumonitis [COVID-19 acute respiratory distress syndrome (ARDS)]. Intrinsic coagulation also induces the contact-kinin pathway of inflammation. A major product of this pathway, bradykinin causes oedema with ground glass opacities (GGO) on imaging in early COVID-19. Bradykinin also causes release of the pleiotrophic cytokine IL-6, which causes lymphocyte recruitment. Thromobosis and lymphocytic pneumonitis are hallmark features of COVID-19 ARDS. In this review we examine the literature with particular reference to the contact-kinin pathway. Measurements of platelets, lymphocytes and APTT should be undertaken in severe infections to stratify for risk of developing ARDS.

Dynamic changes in radiological parameters, immune cells, selected miRNAs, and cytokine levels in peripheral blood of patients with severe COVID‑19

The present study aimed to investigate the dynamic changes in peripheral blood leucocyte subpopulations, cytokine and miRNA levels, and changes in computed tomography (CT) scores in patients with severe coronavirus disease 2019 (COVID-19) (n=14) and age-matched non-COVID-19 volunteers (n=17), which were included as a reference control group. All data were collected on the day of patient admission (day 0) and on the 7th, 14th and 28th days of follow-up while CT of the lungs was performed on weeks 2, 8, 24 and 48. On day 0, lymphopenia and leucopenia were detected in most patients with COVID-19, as well as an increase in the percentage of banded neutrophils, B cells, and CD4+ Treg cells, and a decrease in the content of PD-1low T cells, classical, plasmacytoid, and regulatory dendritic cells. On day 7, the percentage of T and natural killer cells decreased with a concurrent increase in B cells, but returned to the initial level after treatment discharge. The content of different T and dendritic cell subsets among CD45+ cells increased during two weeks and remained elevated, suggesting the activation of an adaptive immune response. The increase of PD-1-positive subpopulations of T and non-T cells and regulatory CD4 T cells in patients with COVID-19 during the observation period suggests the development of an inflammation control mechanism. The levels of interferon γ-induced protein 10 (IP-10), tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 decreased on day 7, but increased again on days 14 and 28. C-reactive protein and granulocyte colony-stimulating factor (G-CSF) levels decreased gradually throughout the observation period. The relative expression levels of microRNA (miR)-21-5p, miR-221-3p, miR-27a-3p, miR-146a-5p, miR-133a-3p, and miR-126-3p were significantly higher at the beginning of hospitalization compared to non-COVID-19 volunteers. The plasma levels of all miRs, except for miR-126-3p, normalized within one week of treatment. At week 48, CT scores were most prominently correlated with the content of lymphocytes, senescent memory T cells, CD127+ T cells and CD57+ T cells, and increased concentrations of G-CSF, IP-10, and macrophage inflammatory protein-1α.

Th-1, Th-2, Th-9, Th-17, Th-22 type cytokine concentrations of critical COVID-19 patients after treatment with Remdesivir

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the world causing a pandemic known as coronavirus disease 2019 (COVID-19). Cytokine storm was directly correlated with severity of COVID-19 syndromes. We evaluated the levels of 13 cytokines in ICU hospitalized COVID-19 patients (n=29) before, and after treatment with Remdesivir as well as in healthy controls (n=29). Blood samples were obtained from ICU patients during ICU admission (before treatment) and 5 days after treatment with Remdesivir. A group of 29 age- and gender-matched healthy controls was also studied. Cytokine levels were evaluated by multiplex immunoassay method using a fluorescence labeled cytokine panel. In comparison to cytokine levels measured at ICU admission, serum levels were reduced of IL-6 (134.75 pg/mL vs. 20.73 pg/mL, P< 0.0001), TNF-α (121.67 pg/mL vs. 10.15 pg/mL, P< 0.0001) and IFN-γ (29.69 pg/mL vs. 22.27 pg/mL, P= 0.005), whereas serum level was increased of IL-4 (8.47 pg/mL vs. 12.44 pg/mL, P= 0.002) within 5 days after Remdesivir treatment. Comparing with before treatment, Remdesivir significantly reduced the levels of inflammatory (258.98 pg/mL vs. 37.43 pg/mL, P< 0.0001), Th1-type (31.24 pg/mL vs. 24.46 pg/mL, P= 0.007), and Th17-type (36.79 pg/mL vs. 26.22 pg/mL, P< 0.0001) cytokines in critical COVID-19 patients. However, after Remdesivir treatment, the concentrations of Th2-type cytokines were significantly higher than before treatment (52.69 pg/mL vs. 37.09 pg/mL, P< 0.0001). In conclusion, Remdesivir led to decrease levels of Th1-type and Th17-type cytokines and increase Th2-type cytokines in critical COVID-19 patients 5 days after treatment.

Cytokine Levels and Severity of Illness Scoring Systems to Predict Mortality in COVID-19 Infection

Various scoring systems and cytokines have been cited as predicting disease severity in COVID-19 infection. This study analyzed the link between mortality rate, levels of cytokines, and scoring systems such as the Glasgow Coma Scale (GCS), Acute Physiologic Assessment and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), and Charlson Comorbidity Index in patients infected with COVID-19. Adult patients infected with COVID-19 were followed up in the intensive care unit (ICU) and analyzed prospectively. We measured serum cytokine levels (Interleukin-10 (IL-10), Interleukin-8 (IL-8), Interleukin-6 (IL-6), Interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and High mobility group box 1 (HMGB-1)) and recorded GCS, APACHE II, SOFA, and Charlson comorbidity index scores on admission to the ICU. Receiver operating curve (ROC) analysis was performed to predict mortality from IL-1β, IL-6 IL-10, IL-8, TNF-α, and HMGB-1 values. Study participants were grouped as follows: Group A, survivors, and Group B, deceased, during the 28-day follow-up. The mean age was 65.69 (±13.56) in Group A (n = 36) and 70.85 (±10.06) in Group B (n = 27). The female/male ratio was 23/40. Age, sex, body mass index (BMI), comorbid illnesses, GCS, APACHE II, SOFA, and Charlson scores, duration of hospitalization or ICU admission, therapeutic choices, and lymphocyte, PMNL, NLR, platelet, D-dimer, fibrinogen, GGT, CRP, procalcitonin, and lactate levels were similar between the groups. The frequency of acute kidney injury (AKI) was higher in Group B (p = 0.005). Serum IL-10, IL-8, IL-6, IL-1β, TNF-α, HMGB-1, ferritin, and LDH values were higher, and PaO₂/FiO₂ was lower in Group B than in Group A. ROC analysis showed that there was an association between serum IL-1β (>1015.7), serum IL-6 (>116.7), serum IL-8 (>258.4), serum IL-10 (>247.5), serum TNF-α (>280.7), and serum HMGB-1 (>23.5) and mortality. AKI gave rise to a greater risk of mortality (odds ratio: 7.081, p = 0.014). Mortality was associated with serum IL-10, IL-8, IL-6, IL-1β, TNF-α, and HMGB-1 but not with GCS, APACHE II, SOFA, or Charlson comorbidity index scores. AKI increased the risk of mortality by seven times. Our findings suggest that cytokine levels (serum IL-10, IL-8, IL-6, IL-1β, TNF-α, and HMGB-1) were predictors of mortality in COVID-19 infection. In addition, our results might give an opinion about the course of COVID-19 infection.

Immunophenotyping characteristics of COVID-19 patients: Peripheral blood CD8+ HLA-DR+ T cells as a biomarker for mortality outcome

INTRODUCTION

The goal of this study was to identify biomarker(s) to assign risk of mortality in COVID-19 patients to improve intensive care unit (ICU) and coronary care unit  management. A total of 100 confirmed COVID-19 patients admitted at Imam Khomeini Hospital in Tehran, were compared to 70 control subjects. Peripheral blood leukocyte was studied using staining reagents included CD3, CD4, CD8, HLA-DR, CD19, CD16, and CD56. The immunophenotyping analysis was evaluated using the FACSCalibur instrument. To investigate the cell density of lung infiltrating T cells, postmortem slides of needle necropsies taken from the lung tissue of 3 critical patients were evaluated by immunohistochemistry staining. The number of lymphocyte subpopulations was significantly lower in COVID-19 patients than in the control group. Regarding the disease severity, the absolute count of T, NK, and HLA-DR+ T cells were significantly reduced in severe patients compared to the moderate ones. The critical patients had a significantly lower count of CD8-HLA-DR+ T cells than the moderate cases. Regarding the disease mortality, based on univariate analysis, the count of HLA-DR+ T, CD8- HLA-DR+ T, and CD8+ HLA-DR+ T cells was associated with mortality in COVID-19 patients. Receiver operating characteristic curve analysis showed the count of CD8+ HLA-DR+ T cells is the best candidate as a biomarker for mortality outcome. Furthermore, pulmonary infiltration of T cells in the lung tissue showed only slight infiltrations of CD3+ T cells, with an equal percentage of CD4+ and CD8+ T cell subpopulation in the lung tissue. These findings suggest that close monitoring of the value of CD8+ HLA-DR+ T cells in COVID-19 patients may be helpful to identify high-risk patients. However, further studies with larger sample size are needed.

Immunomodulation Effect of Convalescent Plasma Therapy in Severe - Critical COVID-19 Patients

Introduction

Convalescent plasma therapy (CPT) is an alternative therapy for managing COVID-19, but its use is still controversial.

Objective

Analyzing the effectiveness of CPT in modulating immune responses based on SARS-COV-2 anti-spike protein receptor-binding domain (s-RBD) IgG, inflammatory cytokines (IL-6 and IL-4), and mortality in severe-critical COVID-19 patients.

Methods

This study was an observational analytical with a prospective cohort design. The number of participants was 39 patients from June to December 2020. The participants received CPT and was tested for blood analysis such as IL-4, IL-6 and s-RBD IgG. The data were taken a day before CPT, 1st day, 2nd day, and 7th day after CPT. The analysis included Friedman, Pearson correlation, and Mann-Whitney test which is significant if p <0.05.

Results

The value of participant's s-RBD IgG before CPT was 91.49 (0.43-3074.73) AU/mL and the 7th day post-CPT, s-RBD IgG value of 1169.79 (6.48-5577.91) AU/mL (p <0.001). The IL-4 value before CPT was 1.78 (0.85-5.21) ng/mL and the 7th day post-CPT, IL-4 value of 1.97 (0.87-120.30) ng/mL (p = 0.401). The condition was also found in IL-6 value, in which the IL-4 value participant before CPT was 109.61 (0.73-4701.63) ng/mL and the 7th day post-CPT, IL-6 value of 1.97 (0.87-120.30) ng/mL (p = 0.401). No significant correlation found between increased s-RBD IgG level with increased IL-4 and decreased IL-6 before and after CPT in severe-critical COVID-19 patients (p >0.05). No significant correlation was also found between increased s-RBD IgG levels, IL-4 too, and decreased IL-6 after CPT therapy between deceased and alive patients, both in 1st, 2nd, and 7th days (p >0.05).

Conclusion

No correlation between the increase in s-RBD IgG levels and changes in IL-4 and IL-6 levels. Changes in s-RBD IgG, IL-4, and IL-6 levels are not associated with mortality in severe-critical COVID-19 degree post CPT recipients.

Kinetics of Immune Subsets in COVID-19 Patients Treated with Corticosteroids

RATIONALE

Changes in anti-SARS-CoV-2 defense immune subsets in patients treated with dexamethasone (DXM) for severe COVID-19 and their relation to disease outcomes are poorly understood.

METHODS

Blood-lymphocyte subsets of 110 hospitalized COVID-19 patients were prospectively examined. A first sample was taken at enrollment and a second one 7-10 days later. Total B-, T-lymphocytes, CD4+, CD8+, T-regulatory (Treg), Natural-Killer (NK) and NK T-cells were counted using flow cytometry.

RESULTS

At enrollment, patients with respiratory failure, characterized by DXM failure (intubation/death) or DXM success (hospital discharge) exhibited significantly fewer CD3+, CD4+ and CD8+ cells and B-lymphocytes compared to the control group (no respiratory failure/no DXM). At the time of treatment completion, the DXM-failure group exhibited significantly fewer CD3+, CD4+ and CD8+ cells, memory CD4+ and CD8+ T-lymphocytes, compared to the control and the DXM-success groups and fewer activated CD4+ T-lymphocytes, Tregs and NK cells compared to the control group. At the time of treatment completion, the number of all investigated lymphocyte subsets increased in the DXM-success group and was similar to those of the control group. NK cells significantly decreased over time in the DXM-failure group.

CONCLUSION

The lymphocyte kinetics differ between DXM-treated and control COVID-19 patients and are associated with clinical outcomes.

A comparative study of virus nucleic acid re-positive and non-re-positive patients infected with SARS-CoV-2 Delta variant strain in the Ningxia Hui Autonomous Region

Objective

This study aimed to provide a basis for epidemic prevention and control measures as well as the management of re-positive personnel by analyzing and summarizing the characteristics of re-positive patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant infections discharged from a hospital in the Ningxia Hui Autonomous Region in 2021.

Methods

This case-control study included a total of 45 patients with Delta variant infections diagnosed in the Fourth People's Hospital of the Ningxia Hui Autonomous Region between October 17 and November 28, 2021. Based on the nucleic acid test results post-discharge, the patients were dichotomized into re-positive and non-re-positive groups. Based on the time of the first re-positive test, the re-positive group was further divided into <7 and ≥7 days groups to compare their clinical characteristics and explore the possible influencing factors of this re-positivity.

Results

Of the 45 total patients, 16 were re-positive (re-positivity rate: 35.6%), including four patients who were re-positive after 2 weeks (re-positivity rate: 8.8%). The median time of the first re-positive after discharge was 7 days (IQR: 14-3). The re-positive group was younger than the non-re-positive group (35 vs. 53, P < 0.05), had a higher proportion of patients who were not receiving antiviral therapy (56.2 vs. 17.2%, P < 0.05). The median CT value of nucleic acid in the re-positive group was considerably greater than that at admission (36.7 vs. 22.6 P < 0.05). The findings demonstrated that neutralizing antibody treatment significantly raised the average IgG antibody level in patients, particularly in those who had not received COVID-19 vaccine (P < 0.05). The median lowest nucleic acid CT value of the ≥7 days group during the re-positive period and the immunoglobulin G (IgG) antibody level at discharge were lower than those in the <7 days group (P < 0.05). When compared to the non-positive group, patients in the ≥7 days group had a higher median virus nucleic acid CT value (27.1 vs. 19.2, P < 0.05) and absolute number of lymphocytes at admission (1,360 vs. 952, P < 0.05), and a lower IgG antibody level at discharge (P < 0.05).

Conclusions

In conclusion, this study found that: (1) The re-positivity rate of SARS-CoV-2 Delta variant infection in this group was 35.6%, while the re-positivity rate was the same as that of the original strain 2 weeks after discharge (8.0%). (2) Young people, patients who did not use antiviral therapy or had low IgG antibody levels at discharge were more likely to have re-positive. And the CT value of nucleic acid at the time of initial infection was higher in re-positive group. We speculated that the higher the CT value of nucleic acid at the time of initial infection, the longer the intermittent shedding time of the virus. (3) Re-positive patients were asymptomatic. The median CT value of nucleic acid was > 35 at the re-positive time, and the close contacts were not detected as positive. The overall transmission risk of re-positive patients is low.

Impact of fluvoxamine on outpatient treatment of COVID-19 in Honduras in a prospective observational real-world study

Background: The COVID-19 pandemic has impacted millions of lives globally. While COVID-19 did not discriminate against developed or developing nations, it has been a significant challenge for third world countries like Honduras to have widespread availability of advanced therapies. The concept of early treatment was almost unheard of when early outpatient treatments utilizing repurposed drugs in Latin American countries began showing promising results. One such drug is fluvoxamine, which has shown tremendous potential in two major studies. As a direct result, fluvoxamine was added to the standard of care in a major medical center outpatient COVID-19 clinic. Methods: This is a prospective observational study performed at the Hospital Centro Médico Sampedrano (CEMESA) in San Pedro Sula, Cortes, Honduras in the COVID-19 outpatient clinic. All patients were at least 15 years of age who had presented with mild or moderate signs and symptoms of COVID-19, and who also had a documented positive SARS-CoV-2 antigen or Reverse Transcription Polymerase Chain Reaction (RT-PCR) were included in the study. These patients then were all prescribed fluvoxamine. The cohort of patients who decided to take fluvoxamine were compared for primary endpoints of mortality and hospitalization risk to the cohort who did not take fluvoxamine. Patients were then monitored for 30 days with the first follow up at 7 days and the second follow up at 10-14 days of symptom onset. Categorical variables were compared by Pearson Chi-square test. The Relative risk was calculated using regression models. Continuous variables were compared by t-test and Wilcoxon rank-sum tests. Results: Out of total 657 COVID-19 cases, 594 patients took fluvoxamine and 63 did not take fluvoxamine. A total of five patients (0.76 percent) died, with only one death occurring in the fluvoxamine group. Patients who received fluvoxamine had a significantly lower relative risk of mortality (RR 0.06, p 0.011, 95% CI 0.007-0.516). There was a lower relative risk of hospitalization in the patients who in the fluvoxamine group. (-10 vs. 30 hospitalizations, RR 0.49, p = 0.035, 95% CI 0.26-0.95). There was 73 percent reduction in relative risk of requiring oxygen in the fluvoxamine group (RR 0.27, p < 0.001, 95% CI 0.14-0.54 Mean lymphocytes count on the first follow-up visit was significantly higher in the fluvoxamine group (1.72 vs. 1.38, Δ 0.33, p 0.007, CI 0.09-0.58). Conclusion: The results of our study suggest that fluvoxamine lowers the relative risk of death, hospitalization, and oxygen requirement in COVID 19 patients.

Development of an In Vitro Model of SARS-CoV-Induced Acute Lung Injury for Studying New Therapeutic Approaches

One of the causes of death of patients infected by SARS-CoV-2 is the induced respiratory failure caused by excessive activation of the immune system, the so-called “cytokine storm”, leading to damage to lung tissue. In vitro models reproducing various stages of the disease can be used to explore the pathogenetic mechanisms and therapeutic approaches to treating the consequences of a cytokine storm. We have developed an in vitro test system for simulating damage to the pulmonary epithelium as a result of the development of a hyperinflammatory reaction based on the co-cultivation of pulmonary epithelial cells (A549 cells) and human peripheral blood mononuclear cells (PBMC) primed with lipopolysaccharide (LPS). In this model, after 24 h of co-cultivation, a sharp decrease in the rate of proliferation of A549 cells associated with the intrinsic development of oxidative stress and, ultimately, with the induction of PANoptotic death were observed. There was a significant increase in the concentration of 40 cytokines/chemokines in a conditioned medium, including TNF-α, IFN-α, IL-6, and IL-1a, which corresponded to the cytokine profile in patients with severe manifestation of COVID-19. In order to verify the model, the analysis of the anti-inflammatory effects of well-known substances (dexamethasone, LPS from Rhodobacter sphaeroides (LPS-RS), polymyxin B), as well as multipotent mesenchymal stem cells (MSC) and MSC-derived extracellular vesicles (EVs) was carried out. Dexamethasone and polymyxin B restored the proliferative activity of A549 cells and reduced the concentration of proinflammatory cytokines. MSC demonstrated an ambivalent effect through stimulated production of both pro-inflammatory cytokines and growth factors that regenerate lung tissue. LPS-RS and EVs showed no significant effect. The developed test system can be used to study molecular and cellular pathological processes and to evaluate the effectiveness of various therapeutic approaches for the correction of hyperinflammatory response in COVID-19 patients.

Developing dendritic cell for SARS-CoV-2 vaccine: Breakthrough in the pandemic

Finding a vaccine that can last a long time and effective against viruses with high mutation rates such as SARS-CoV-2 is still a challenge today. The various vaccines that have been available have decreased in effectiveness and require booster administration. As the professional antigen presenting cell, Dendritic Cells can also activate the immune system, especially T cells. This ability makes dendritic cells have been developed as vaccines for some types of diseases. In SARS-CoV-2 infection, T cells play a vital role in eliminating the virus, and their presence can be detected in the long term. Hence, this condition shows that the formation of T cell immunity is essential to prevent and control the course of the disease. The construction of vaccines oriented to induce strong T cells response can be formed by utilizing dendritic cells. In this article, we discuss and illustrate the role of dendritic cells and T cells in the pathogenesis of SARS-CoV-2 infection and summarizing the crucial role of dendritic cells in the formation of T cell immunity. We arrange the basis concept of developing dendritic cells for SARS-CoV-2 vaccines. A dendritic cell-based vaccine for SARS-CoV-2 has the potential to be an effective vaccine that solves existing problems.

Detection of erythroid progenitors and erythrocytopathies in patients with severe COVID-19 disease

OBJECTIVES

To assess the effect of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection on erythropoiesis and red blood cells (RBC) surface markers by evaluating erythroid progenitor cells (CD [cluster of differentiation]71⁺/CD235a⁺) and RBC surface markers (CD235a and CD36), together with various hematological parameters.

METHODS

This case-control study includes 47 participants recruited in the study: 30 patients with coronavirus disease 2019 (COVID-19) and 17 healthy individuals. The COVID-19 patients were recruited from the intensive care unit (ICU) of various hospitals in Makkah, Saudi Arabia. Blood samples were collected during July and September 2021. Red blood cells indices were measured using a CBC analyzer. The expression of CD235a, CD71, and CD36 was obtained using flow cytometry technique. The unpaired t-test was conducted to evaluate the differences in these markers in COVID-19 patients and healthy individuals.

RESULTS

The data showed that more than half of the COVID-19 patients were anemic (64%). Expansion of erythroid progenitors (CD71⁺/CD235a⁺) was detected in the COVID-19 patients. Analysis of the expression of RBC surface markers, such as CD235a and CD36, showed that SARS-CoV-2 was associated with significantly higher expression of these markers in COVID-19 patients.

CONCLUSION

Severe acute respiratory syndrome coronavirus-2 promoted the expansion of erythroid progenitors in the peripheral blood of COVID-19 patients. In addition, the expression of RBC surface markers was higher in COVID-19 patients. The expansion of erythroid progenitors and alteration of RBC surface markers can contribute to erythrocytopathies observed in severe COVID-19 patients and can therefore be used as prognostic factors.

Elevated Levels of Pleiotropic Interleukin-6 (IL-6) and Interleukin-10 (IL-10) are Critically Involved With the Severity and Mortality of COVID-19: An Updated Longitudinal Meta-Analysis and Systematic Review on 147 Studies

Objectives

Disruption in the natural immune reaction due to SARS-CoV-2 infection can initiate a potent cytokine storm among COVID-19 patients. An elevated level of IL-6 and IL-10 during a hyperinflammatory state plays a vital role in increasing the risk of severity and mortality. In this study, we aimed to evaluate the potential of circulating IL-6 and IL-10 levels as biomarkers for detecting the severity and mortality of COVID-19.

Methods

This study was conducted according to the Cochrane Handbook and PRISMA guidelines. Authorized databases were searched to extract suitable studies using specific search terms. RevMan 5.4 was applied for performing the meta-analysis. Mean differences in IL-6 and IL-10 levels were calculated among COVID-19 patients via a random-effects model. NOS scoring, publication bias and sensitivity analyses were checked to ensure study quality.

Results

A total of 147 studies were selected, with 31 909 COVID-19 patients under investigation. In the severity analysis, the mean concentration of IL-6 was significantly higher in the severe COVID-19 cases than in the non-severe cases (MD: 19.98; P < .001; 95% CI: 17.56, 22.40). Similar result was observed for IL-10 mean concentration in severe COVID-19 cases (MD: 1.35; P < .001; 95% CI: 0.90, 1.80). In terms of mortality analysis, circulating IL-6 showed sharp elevation in the deceased patients (MD: 42.11; P < .001; 95% CI: 36.86, 47.36). IL-10 mean concentration was higher in the dead patients than in the survived patients (MD: 4.79; P < .001; 95% CI: 2.83, 6.75). Publication bias was not found except for comparing IL-6 levels with disease severity. Sensitivity analysis also reported no significant deviation from the pooled outcomes.

Conclusions

Elevated levels of circulating IL-6 and IL-10 signifies worsening of COVID-19. To monitor the progression of SARS-CoV-2 infection, IL-6 and IL-10 should be considered as potential biomarkers for severity and mortality detection in COVID-19.

Systematic review registration

INPLASY registration number: INPLASY202240046.

Immunouniverse of SARS-CoV-2

SARS-CoV-2 virus has become a global health problem that has caused millions of deaths worldwide. The infection can present with multiple clinical features ranging from asymptomatic or mildly symptomatic patients to patients with severe or critical illness that can even lead to death. Although the immune system plays an important role in pathogen control, SARS-CoV-2 can drive dysregulation of this response and trigger severe immunopathology. Exploring the mechanisms of the immune response involved in host defense against SARS-CoV-2 allows us to understand its immunopathogenesis and possibly detect features that can be used as potential therapies to eliminate the virus. The main objective of this review on SARS-CoV-2 is to highlight the interaction between the virus and the immune response. We explore the function and action of the immune system, the expression of molecules at the site of infection that cause hyperinflammation and hypercoagulation disorders, the factors leading to the development of pneumonia and subsequent severe acute respiratory distress syndrome which is the leading cause of death in patients with COVID-19.

Long COVID: current status in Japan and knowledge about its molecular background

Even after recovering from coronavirus disease 2019 (COVID-19), patients can experience prolonged complaints, referred to as "long COVID". Similar to reports in Caucasians, a follow-up study in Japan revealed that fatigue, dyspnea, cough, anosmia/dysgeusia, and dyssomnia are common symptoms. Although the precise mode of long COVID remains elusive, multiple etiologies such as direct organ damage by infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), autoimmunity, prolonged inflammatory reactions, and psychiatric impairment seem to be involved. Notably, SARS-CoV-2 is neurotropic, and viral RNA and proteins are continuously detectable in multiple organs, including the brain. Viral proteins exert a number of different toxic effects on cells, suggesting that persistent infection is a key element for understanding long COVID. Here, we first reviewed the current status of long COVID in Japan, and then summarized literature that help us understand the molecular background of the symptoms. Finally, we discuss the feasibility of vaccination as a treatment for patients with long COVID.

T-Cell Subsets and Interleukin-10 Levels Are Predictors of Severity and Mortality in COVID-19: A Systematic Review and Meta-Analysis

Background

Many COVID-19 patients reveal a marked decrease in their lymphocyte counts, a condition that translates clinically into immunodepression and is common among these patients. Outcomes for infected patients vary depending on their lymphocytopenia status, especially their T-cell counts. Patients are more likely to recover when lymphocytopenia is resolved. When lymphocytopenia persists, severe complications can develop and often lead to death. Similarly, IL-10 concentration is elevated in severe COVID-19 cases and may be associated with the depression observed in T-cell counts. Accordingly, this systematic review and meta-analysis aims to analyze T-cell subsets and IL-10 levels among COVID-19 patients. Understanding the underlying mechanisms of the immunodepression observed in COVID-19, and its consequences, may enable early identification of disease severity and reduction of overall morbidity and mortality.

Methods

A systematic search was conducted covering PubMed MEDLINE, Scopus, Web of Science, and EBSCO databases for journal articles published from December 1, 2019 to March 14, 2021. In addition, we reviewed bibliographies of relevant reviews and the medRxiv preprint server for eligible studies. Our search covered published studies reporting laboratory parameters for T-cell subsets (CD4/CD8) and IL-10 among confirmed COVID-19 patients. Six authors carried out the process of data screening, extraction, and quality assessment independently. The DerSimonian-Laird random-effect model was performed for this meta-analysis, and the standardized mean difference (SMD) and 95% confidence interval (CI) were calculated for each parameter.

Results

A total of 52 studies from 11 countries across 3 continents were included in this study. Compared with mild and survivor COVID-19 cases, severe and non-survivor cases had lower counts of CD4/CD8 T-cells and higher levels of IL-10.

Conclusion

Our findings reveal that the level of CD4/CD8 T-cells and IL-10 are reliable predictors of severity and mortality in COVID-19 patients. The study protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO); registration number CRD42020218918.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020218918, identifier: CRD42020218918.

Pathological effects of SARS-CoV-2 on hematological and immunological cells: Alterations in count, morphology, and function

The novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19 outbreak, spread rapidly and infected more than 140 million people with more than three million victims worldwide. The SARS-CoV-2 causes destructive changes in the immunological and hematological system of the host. These alterations appear to play a critical role in disease pathology and the emerging of clinical manifestations. In this review, we aimed to discuss the effect of COVID-19 on the count, function and morphology of immune and blood cells and the role of these changes in the pathophysiology of the disease. Knowledge of these changes may help with better management and treatment of COVID-19 patients.

Monitoring of Torque Teno virus DNAemia in critically ill COVID-19 patients: May it help to predict clinical outcomes?

Background

: Torque teno virus (TTV) DNA load in plasma directly associates with the net state of immunosuppression and inflammation in different clinical settings, including transplantation and chronic inflammatory diseases.

Objectives

: We investigated whether plasma TTV DNA load may predict the occurrence of certain infectious events and overall mortality in critically ill COVID-19 patients.

Patients and Methods

: 50 patients (median age, 65.5 years) were recruited. TTV DNA load was quantitated in serial plasma specimens by real-time PCR. Serum levels of interleukin-6, C-reactive protein, ferritin, lactate dehydrogenase, Gamma-Glutamyl Transferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST) and absolute lymphocyte counts (ALC) in paired specimens were available. Nosocomial bloodstream infections and ventilator-associated pneumonia and overall mortality were the clinical outcomes.

Results

: TTV DNA was detected in 38 patients (76%). A weak inverse correlation (Rho=-0.28; P = 0.004) was observed between TTV DNA loads and ALC. No direct correlation was found between TTV DNA load and serum levels of any of the above biomarkers. Patients with detectable TTV DNA had an increased risk of subsequently developing infectious events (HR 9.28; 95% CI, 1.29–69.5; P = 0.03). A trend (P = 0.05) towards higher TTV DNA area under a curve between days 7 and 17 after ICU admission (AUC_7–17) was observed in patients who died, as compared to survivors.

Conclusion

: Our findings suggested that plasma TTV DNA load monitoring may be helpful for predicting the occurrence of severe nosocomial infections and mortality in critically ill COVID-19 patients.

Hematopoietic responses to SARS-CoV-2 infection

Under physiological conditions, hematopoietic stem and progenitor cells (HSPCs) in the bone marrow niches are responsible for the highly regulated and interconnected hematopoiesis process. At the same time, they must recognize potential threats and respond promptly to protect the host. A wide spectrum of microbial agents/products and the consequences of infection-induced mediators (e.g. cytokines, chemokines, and growth factors) can have prominent impact on HSPCs. While COVID-19 starts as a respiratory tract infection, it is considered a systemic disease which profoundly alters the hematopoietic system. Lymphopenia, neutrophilia, thrombocytopenia, and stress erythropoiesis are the hallmark of SARS-CoV-2 infection. Moreover, thrombocytopenia and blood hypercoagulability are common among COVID-19 patients with severe disease. Notably, the invasion of erythroid precursors and progenitors by SARS-CoV-2 is a cardinal feature of COVID-19 disease which may in part explain the mechanism underlying hypoxia. These pieces of evidence support the notion of skewed steady-state hematopoiesis to stress hematopoiesis following SARS-CoV-2 infection. The functional consequences of these alterations depend on the magnitude of the effect, which launches a unique hematopoietic response that is associated with increased myeloid at the expense of decreased lymphoid cells. This article reviews some of the key pathways including the infectious and inflammatory processes that control hematopoiesis, followed by a comprehensive review that summarizes the latest evidence and discusses how SARS-CoV-2 infection impacts hematopoiesis.

Clinical features and independent predictors for recurrence of positive SARS-CoV-2 RNA: A propensity score-matched analysis

Patients with COVID‐19 may be recurrence positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RNA after being cured and discharged from the hospital. The aim of this study was to explore independent influencing factors as markers for predicting positive SARS‐CoV‐2 RNA recurrence. The study included 601 COVID‐19 patients who were cured and discharged from the Public and Health Clinic Centre of Chengdu from January 2020 to March 2021, and the recurrence positive of patients within 6 weeks after SARS‐CoV‐2 RNA turned negative was followed up. We used propensity score matching to eliminate the influence of confounding factors, and multivariate Logistic regression analysis was used to determine the independent influencing factors for positive SARS‐CoV‐2 RNA recurrence. Multivariate Logistic regression showed that the elevated serum potassium (odds ratio [OR] = 6.537, 95% confidence interval [CI]: 1.864–22.931, p = 0.003), elevated blood chlorine (OR = 1.169, 95% CI: 1.032–1.324, p = 0.014) and elevated CD3⁺CD4⁺ count (OR = 1.003, 95% CI: 1.001–1.004, p < 0.001) were identified as independent risk factors for positive SARS‐CoV‐2 RNA recurrence (p < 0.05). The difference in virus shedding duration (OR = 1.049, 95% CI: 1.000–1.100, p = 0.05) was borderline statistically significant. For sensitivity analysis, we included virus shedding duration as a categorical variable in the model again and found that the OR value related to recurrence positively increased with delayed virus shedding duration, and the trend test showed a statistical difference (P trend = 0.03). Meanwhile, shortening of activated partial prothrombinase time (OR = 0.908, 95% CI: 0.824–1.000, p = 0.049) was identified as an independent protection factor for SARS‐CoV‐2 RNA recurrence positive. We have identified independent factors that affect the recurrence of SARS‐CoV‐2 RNA positive. It is recommended that doctors pay attention to these indicators when first admitted to the hospital.

Impact of the Innate Inflammatory Response on ICU Admission and Death in Hospitalized Patients with COVID-19

Objective: To describe the capacity of a broad spectrum of cytokines and growth factors to predict ICU admission and/or death in patients with severe COVID-19. Design: An observational, analytical, retrospective cohort study with longitudinal follow-up. Setting: Hospital Universitario Príncipe de Asturias (HUPA). Participants: 287 patients diagnosed with COVID-19 admitted to our hospital from 24 March to 8 May 2020, followed until 31 August 2020. Main outcome measures: Profiles of immune response (IR) mediators were determined using the Luminex Multiplex technique in hospitalized patients within six days of admission by examining serum levels of 62 soluble molecules classified into the three groups: adaptive IR-related cytokines (n = 19), innate inflammatory IR-related cytokines (n = 27), and growth factors (n = 16). Results: A statistically robust link with ICU admission and/or death was detected for increased serum levels of interleukin (IL)-6, IL-15, soluble (s) RAGE, IP10, MCP3, sIL1RII, IL-8, GCSF and MCSF and IL-10. The greatest prognostic value was observed for the marker combination IL-10, IL-6 and GCSF. Conclusions: When severe COVID-19 progresses to ICU admission and/or death there is a marked increase in serum levels of several cytokines and chemokines, mainly related to the patient’s inflammatory IR. Serum levels of IL-10, IL-6 and GCSF were most prognostic of the outcome measure.

Immunopathology and Immunosenescence, the Immunological Key Words of Severe COVID-19. Is There a Role for Stem Cell Transplantation?

The outcomes of Coronavirus disease-2019 (COVID-19) vary depending on the age, health status and sex of an individual, ranging from asymptomatic to lethal. From an immunologic viewpoint, the final severe lung damage observed in COVID-19 should be caused by cytokine storm, driven mainly by interleukin-6 and other pro-inflammatory cytokines. However, which immunopathogenic status precedes this "cytokine storm" and why the male older population is more severely affected, are currently unanswered questions. The aging of the immune system, i.e., immunosenescence, closely associated with a low-grade inflammatory status called "inflammageing," should play a key role. The remodeling of both innate and adaptive immune response observed with aging can partly explain the age gradient in severity and mortality of COVID-19. This review discusses how aging impacts the immune response to the virus, focusing on possible strategies to rejuvenate the immune system with stem cell-based therapies. Indeed, due to immunomodulatory and anti-inflammatory properties, multipotent mesenchymal stem cells (MSCs) are a worth-considering option against COVID-19 adverse outcomes.

Association of Clinical and Immunological Characteristics With Disease Severity and Outcomes in 211 Patients With COVID-19 in Wuhan, China

Background

Coronavirus disease 2019 (COVID-19) has posed a great threat to global public health. There remains an urgent need to address the clinical significance of laboratory finding changes in predicting disease progression in COVID-19 patients. We aimed to analyze the clinical and immunological features of severe and critically severe patients with COVID-19 in comparison with non-severe patients and identify risk factors for disease severity and clinical outcome in COVID-19 patients.

Methods

The consecutive records of 211 patients with COVID-19 who were admitted to Zhongnan Hospital of Wuhan University from December 2019 to February 2020 were retrospectively reviewed.

Results

Of the 211 patients with COVID-19 recruited, 111 patients were classified as non-severe, 59 as severe, and 41 as critically severe cases. The median age was obviously higher in severe and critically severe cases than in non-severe cases. Severe and critically severe patients showed more underlying comorbidities than non-severe patients. Fever was the predominant presenting symptom in COVID-19 patients, and the duration of fever was longer in critically severe patients. Moreover, patients with increased levels of serum aminotransferases and creatinine (CREA) were at a higher risk for severe and critical COVID-19 presentations. The serum levels of IL-6 in severe and critically severe patients were remarkably higher than in non-severe patients. Lymphopenia was more pronounced in severe and critically severe patients compared with non-severe patients. Lymphocyte subset analysis indicated that severe and critically severe patients had significantly decreased count of lymphocyte subpopulations, such as CD4+ T cells, CD8+ T cells and B cells. A multivariate logistic analysis indicated that older age, male sex, the length of hospital stay, body temperature before admission, comorbidities, higher white blood cell (WBC) counts, lower lymphocyte counts, and increased levels of IL-6 were significantly associated with predicting the progression to severe stage of COVID-19.

Conclusion

Older age, male sex, underlying illness, sustained fever status, abnormal liver and renal functions, excessive expression of IL-6, lymphopenia, and selective loss of peripheral lymphocyte subsets were related to disease deterioration and clinical outcome in COVID-19 patients. This study would provide clinicians with valuable information for risk evaluation and effective interventions for COVID-19.

Features of HLA class I expression and its clinical relevance in SARS-CoV-2: What do we know so far?

Modifications in HLA‐I expression are found in many viral diseases. They represent one of the immune evasion strategies most widely used by viruses to block antigen presentation and NK cell response, and SARS‐CoV‐2 is no exception. These alterations result from a combination of virus‐specific factors, genetically encoded mechanisms, and the status of host defences and range from loss or upregulation of HLA‐I molecules to selective increases of HLA‐I alleles. In this review, I will first analyse characteristic features of altered HLA‐I expression found in SARS‐CoV‐2. I will then discuss the potential factors underlying these defects, focussing on HLA‐E and class‐I‐related (like) molecules and their receptors, the most documented HLA‐I alterations. I will also draw attention to potential differences between cells transfected to express viral proteins and those presented as part of authentic infection. Consideration of these factors and others affecting HLA‐I expression may provide us with improved possibilities for research into cellular immunity against viral variants.

A Dynamic Bayesian Model for Identifying High-Mortality Risk in Hospitalized COVID-19 Patients

As Coronavirus Disease 2019 (COVID-19) hospitalization rates remain high, there is an urgent need to identify prognostic factors to improve patient outcomes. Existing prognostic models mostly consider the impact of biomarkers at presentation on the risk of a single patient outcome at a single follow up time. We collected data for 553 Polymerase Chain Reaction (PCR)-positive COVID-19 patients admitted to hospital whose eventual outcomes were known. The data collected for the patients included demographics, comorbidities and laboratory values taken at admission and throughout the course of hospitalization. We trained multivariate Markov prognostic models to identify high-risk patients at admission along with a dynamic measure of risk incorporating time-dependent changes in patients' laboratory values. From the set of factors available upon admission, the Markov model determined that age >80 years, history of coronary artery disease and chronic obstructive pulmonary disease increased mortality risk. The lab values upon admission most associated with mortality included neutrophil percentage, red blood cells (RBC), red cell distribution width (RDW), protein levels, platelets count, albumin levels and mean corpuscular hemoglobin concentration (MCHC). Incorporating dynamic changes in lab values throughout hospitalization lead to dramatic gains in the predictive accuracy of the model and indicated a catalogue of variables for determining high-risk patients including eosinophil percentage, white blood cells (WBC), platelets, pCO2, RDW, large unstained cells (LUC) count, alkaline phosphatase and albumin. Our prognostic model highlights the nuance of determining risk for COVID-19 patients and indicates that, rather than a single variable, a range of factors (at different points in hospitalization) are needed for effective risk stratification.