The underlying changes and predicting role of peripheral blood inflammatory cells in severe COVID-19 patients: A sentinel?

Bronchial Asthma and COVID-19: Etiology, Pathological Triggers, and Therapeutic Considerations

Bronchial asthma (BA) continues to be a difficult disease to diagnose. Various factors have been described in the development of BA, but to date, there is no clear evidence for the etiology of this chronic disease. The emergence of COVID-19 has contributed to the pandemic course of asthma and immunologic features. However, there are no unambiguous data on asthma on the background and after COVID-19. There is correlation between various trigger factors that provoke the development of bronchial asthma. It is now obvious that the SARS-CoV-2 virus is one of the provoking factors. COVID-19 has affected the course of asthma. Currently, there is no clear understanding of whether asthma progresses during or after COVID-19 infection. According to the results of some studies, a significant difference was identified between the development of asthma in people after COVID-19. Mild asthma and moderate asthma do not increase the severity of COVID-19 infection. Nevertheless, oral steroid treatment and hospitalization for severe BA were associated with higher COVID-19 severity. The influence of SARS-CoV-2 infection is one of the protective factors. It causes the development of severe bronchial asthma. The accumulated experience with omalizumab in patients with severe asthma during COVID-19, who received omalizumab during the pandemic, has strongly suggested that continued treatment with omalizumab is safe and may help prevent the severe course of COVID-19. Targeted therapy for asthma with the use of omalizumab may also help to reduce severe asthma associated with COVID-19. However, further studies are needed to prove the effect of omalizumab. Data analysis should persist, based on the results of the course of asthma after COVID-19 with varying degrees of severity.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.

Systemic inflammation and quality of life in patients with coronavirus disease: interrelation features

OBJECTIVE

Aim: To characterize the features of the interrelation of systemic inflammation with the quality of life of patients with coronary virus disease.

PATIENTS AND METHODS

Materials and Methods: 30 patients were examined 1 month after inpatient treatment for COVID-19. Quality of life (QoL) of patients was determined according to the questionnaire Medical Outcomes Study - 36-item Short Form (SF-36). The glucose level, circulating immune complexes (CICs), concentration of immunoglobulin (Ig) A, interleukin (IL)-8 and IL-33 levels were determined in the blood serum of patients.

RESULTS

Results: QoL of patients after coronavirus disease is significantly deteriorated: patients note a significant limitation in physical functioning, pain perception, vitality, role-physical and social functioning and mental health. The increase in glycemia and glycated hemoglobin levels in post-COVID-19 patients was significantly associated with the deterioration of patients` general health (GH) (r = -0,228; (p=0,040) and (r = -0,280; (p=0,014), respectively). The IL-33 concentration in such patients correlated directly with role-physical functioning (RP) (r = 0,385; p=0,029). The CICs level decline was associated with deterioration of RP (r = 0,227; p=0,042) and GH (r = 0,227; p=0,041).

CONCLUSION

Conclusions: The study of clinical-functional, biochemical, immunological and psychological indicators, quality of life, and their mutual influences should be included in the development of the program for the diagnosis, treatment, and rehabilitation of patients after the transfer of COVID-19 at the outpatient stage of treatment by doctors of general practice-family medicine.

The Management of COVID-19-Related Coagulopathy: A Focus on the Challenges of Metabolic and Vascular Diseases

The course of COVID-19 is highly dependent on the associated cardiometabolic comorbidities of the patient, which worsen the prognosis of coronavirus infection, mainly due to systemic inflammation, endothelium dysfunction, and thrombosis. A search on the recent medical literature was performed in five languages, using the PubMed, Embase, Cochrane, and Google Scholar databases, for the review of data regarding the management of patients with a high risk for severe COVID-19, focusing on the associated coagulopathy. Special features of COVID-19 management are presented, based on the underlying conditions (obesity, diabetes mellitus, and cardiovascular diseases), emphasizing the necessity of a modern, holistic approach to thromboembolic states. The latest findings regarding the most efficient therapeutic approaches are included in the article, offering guidance for medical professionals in severe, complicated cases of SARS-CoV-2 infection. We can conclude that severe COVID-19 is closely related to vascular inflammation and intense cytokine release leading to hemostasis disorders. Overweight, hyperglycemia, cardiovascular diseases, and old age are important risk factors for severe outcomes of coronavirus infection, involving a hypercoagulable state. Early diagnosis and proper therapy in complicated SARS-CoV-2-infected cases could reduce mortality and the need for intensive care during hospitalization in patients with cardiometabolic comorbidities.

Hematocytological Clues of Peripheral Blood in Different Clinical Presentations of COVID-19

Background

To gain insight into the pathogenesis and clinical course of COVID-19 from a historical perspective, we reviewed paraclinical diagnostic tools of this disease and prioritized the patients with a more severe form of disease admitted to intensive care units (ICUs). The objective was to better predict the course and severity of the disease by collecting more paraclinical data, specifically by examining the relationship between hematological findings and cytological variation of blood neutrophils and monocytes.

Methods

This retrospective study was conducted on 112 patients with confirmed COVID-19 admitted to Imam Hossein Hospital (Tehran, Iran) from August to September 2020. Peripheral blood smears of these patients were differentiated according to several cytological variations of neutrophils and monocytes, and the correlation to the severity of the disease was specified.

Results

The mean percentages of degenerated monocytes, degenerated granulocytes, and spiky biky neutrophils were significantly different among critical and non-critical patients (P<0.05). Degenerated monocytes and granulocytes were higher in critical patients as opposed to spiky biky neutrophils, which were higher among non-critical ones. Comparing the peripheral blood smears of COVID-19 patients (regarding pulmonary involvement in chest computed tomography [CT] scans [subtle, mild, moderate, and severe groups]), the twisted form of neutrophils was significantly higher in the subtle group than in the mild and moderate groups (P=0.003).

Conclusion

Different cytological morphologies of neutrophils and monocytes, including degenerated monocytes, degenerated granulocytes, and spiky biky and twisted neutrophils, could help to predict the course and severity of the disease.

[Clinical features of 23 neonates infected with Omicron variant of severe acute respiratory syndrome coronavirus 2]

OBJECTIVES

To summarize the clinical features of neonates infected with Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

The medical data of 23 neonates with Omicron variant of SARS-CoV-2 infection admitted to the City North Campus of Urumqi First People's Hospital from October to December 2022 were retrospectively reviewed.

RESULTS

All 23 infants had a history of exposure to confirmed caregivers with SARS-CoV-2 infection after birth, and none of them was vertically transmitted. Clinical classification: 5 cases of asymptomatic infection, 18 cases of mild infection, and no cases of moderate, severe, or critically ill. The first symptoms were fever in 13 cases, cough in 3 cases, nasal congestion in 1 case, and diarrhea in 1 case. Blood white blood cell counts decreased in 2 cases, and C-reactive protein increased in 1 case. Seven infants underwent chest X-ray examination due to cough or shortness of breath, and one of which showed focal exudative changes, while the rest showed no abnormal changes. All infants were discharged after symptomatic treatment and the median hospital stay was 6 days. The duration of nucleic acid positivity of SARS-CoV-2 was negatively correlated with N gene Ct values and ORF1ab gene Ct values (rs=-0.719 and -0.699, respectively; P<0.05). One month after discharge, all infants had no symptoms or signs of nucleic acid re-positivity.

CONCLUSIONS

The clinical manifestations are usually mild or asymptomatic in neonates infected with SARS-CoV-2 Omicron variant. The lower the Ct values of the N and ORF1ab genes of SARS-CoV-2, the longer the duration of nucleic acid positivity. Neonates infected with SARS-CoV-2 Omicron variant can have a good prognosis after symptomatic treatment.

Deciphering suppressive effects of Lianhua Qingwen Capsule on COVID-19 and synergistic effects of its major botanical drug pairs

The COVID-19 pandemic has resulted in excess deaths worldwide. Conventional antiviral medicines have been used to relieve the symptoms, with limited therapeutic effect. In contrast, Lianhua Qingwen Capsule is reported to exert remarkable anti-COVID-19 effect. The current review aims to: 1) uncover the main pharmacological actions of Lianhua Qingwen Capsule for managing COVID-19; 2) verify the bioactive ingredients and pharmacological actions of Lianhua Qingwen Capsule by network analysis; 3) investigate the compatibility effect of major botanical drug pairs in Lianhua Qingwen Capsule; and 4) clarify the clinical evidence and safety of the combined therapy of Lianhua Qingwen Capsule and conventional drugs. Numerous bioactive ingredients in Lianhu Qingwen, such as quercetin, naringenin, β-sitosterol, luteolin, and stigmasterol, were identified to target host cytokines, and to regulate the immune defence in response to COVID-19. Genes including androgen receptor (AR), myeloperoxidase (MPO), epidermal growth factor receptor (EGFR), insulin (INS), and aryl hydrocarbon receptor (AHR) were found to be significantly involved in the pharmacological actions of Lianhua Qingwen Capsule against COVID-19. Four botanical drug pairs in Lianhua Qingwen Capsule were shown to have synergistic effect for the treatment of COVID-19. Clinical studies demonstrated the medicinal effect of the combined use of Lianhua Qingwen Capsule and conventional drugs against COVID-19. In conclusion, the four main pharmacological mechanisms of Lianhua Qingwen Capsule for managing COVID-19 are revealed. Therapeutic effect has been noted against COVID-19 in Lianhua Qingwen Capsule.

Mixed storm in SARS-CoV-2 infection: A narrative review and new term in the Covid-19 era

Coronavirus disease 2019 (Covid-19) is caused by a novel severe acute respiratory syndrome coronavirus virus type 2 (SARS-CoV-2) leading to the global pandemic worldwide. Systemic complications in Covid-19 are mainly related to the direct SARS-CoV-2 cytopathic effects, associated hyperinflammation, hypercytokinemia, and the development of cytokine storm (CS). As well, Covid-19 complications are developed due to the propagation of oxidative and thrombotic events which may progress to a severe state called oxidative storm and thrombotic storm (TS), respectively. In addition, inflammatory and lipid storms are also developed in Covid-19 due to the activation of inflammatory cells and the release of bioactive lipids correspondingly. Therefore, the present narrative review aimed to elucidate the interrelated relationship between different storm types in Covid-19 and the development of the mixed storm (MS). In conclusion, SARS-CoV-2 infection induces various storm types including CS, inflammatory storm, lipid storm, TS and oxidative storm. These storms are not developing alone since there is a close relationship between them. Therefore, the MS seems to be more appropriate to be related to severe Covid-19 than CS, since it develops in Covid-19 due to the intricate interface between reactive oxygen species, proinflammatory cytokines, complement activation, coagulation disorders, and activated inflammatory signaling pathway.

Identification of Parameters Representative of Immune Dysfunction in Patients with Severe and Fatal COVID-19 Infection: a Systematic Review and Meta-analysis

Abnormal immunological indicators associated with disease severity and mortality in patients with COVID-19 have been reported in several observational studies. However, there are marked heterogeneities in patient characteristics and research methodologies in these studies. We aimed to provide an updated synthesis of the association between immune-related indicators and COVID-19 prognosis. We conducted an electronic search of PubMed, Scopus, Ovid, Willey, Web of Science, Cochrane library, and CNKI for studies reporting immunological and/or immune-related parameters, including hematological, inflammatory, coagulation, and biochemical variables, tested on hospital admission of COVID-19 patients with different severities and outcomes. A total of 145 studies were included in the current meta-analysis, with 26 immunological, 11 hematological, 5 inflammatory, 4 coagulation, and 10 biochemical variables reported. Of them, levels of cytokines, including IL-1β, IL-1Ra, IL-2R, IL-4, IL-6, IL-8, IL-10, IL-18, TNF-α, IFN-γ, IgA, IgG, and CD4+ T/CD8+ T cell ratio, WBC, neutrophil, platelet, ESR, CRP, ferritin, SAA, D-dimer, FIB, and LDH were significantly increased in severely ill patients or non-survivors. Moreover, non-severely ill patients or survivors presented significantly higher counts of lymphocytes, monocytes, lymphocyte/monocyte ratio, eosinophils, CD3+ T,CD4+T and CD8+T cells, B cells, and NK cells. The currently updated meta-analysis primarily identified a hypercytokinemia profile with the severity and mortality of COVID-19 containing IL-1β, IL-1Ra, IL-2R, IL-4, IL-6, IL-8, IL-10, IL-18, TNF-α, and IFN-γ. Impaired innate and adaptive immune responses, reflected by decreased eosinophils, lymphocytes, monocytes, B cells, NK cells, T cells, and their subtype CD4+ and CD8+ T cells, and augmented inflammation, coagulation dysfunction, and nonpulmonary organ injury, were marked features of patients with poor prognosis. Therefore, parameters of immune response dysfunction combined with inflammatory, coagulated, or nonpulmonary organ injury indicators may be more sensitive to predict severe patients and those non-survivors.

Gas Chromatography-Mass Spectrometry Technology: Application in the Study of Inflammatory Mechanism in COVID-19 Patients

SARS-CoV-2 infection in the human body induces a severe storm of inflammatory factors. However, its specific mechanism is still not clear. Gas chromatography-mass spectrometry (GC-MS) technology is expected to explain the possible mechanism of the disease by detecting differential metabolites. 15 COVID-19 patients and healthy controls were included in this study. Immune indicators such as hs CRP and cytokines were detected to reflect the level of inflammation in patients with COVID-19. The distribution of lymphocytes and subpopulations in peripheral whole blood were detected using flow cytometry to assess the immune function of COVID-19 patients. The expression of differential metabolites in serum was analyzed using GC-MS non-targeted metabolomics. The results showed that hs CRP, IL-5/6/8/10 and IFN-α in the serum of COVID-19 patients increased to varying degrees, and CD3/4/8+ T lymphocytes decreased. Additionally, 53 metabolites in the serum of COVID-19 patients were up regulated, 18 metabolites were down regulated, and 8 metabolites remained unchanged. Increased Cholesterol, Lactic Acid and 1-Monopalmitin may be the mechanism that causes excessive inflammation in COVID-19 patients. The increase of D-Allose may be involved in the process of lymphocyte decrease. In conclusion, the significance of our study is to reveal the possible mechanism of inflammatory response in patients with COVID-19 from the perspective of metabolomics. This provided a new idea for the treatment of COVID-19.

Graphical Abstract

Are Lymphocytes and Eosinophils Associated with the COVID-19 Severity: A Large, Retrospective Study

OBJECTIVE

Coronavirus disease 2019 is an ongoing disease with high morbidity and mortality. We aimed to investigate the relationship between demographics, lymphocytes, eosinophils, and the coronavirus disease 2019 severity at hospital admission.

MATERIAL AND METHODS

A retrospective, observational cross-sectional study was carried out with 5828 coronavirus disease 2019 patients between March 11, 2020, and November 30, 2020. Patients were divided into 3 groups according to where they were followed up as an indicator of disease severity, namely outpatients, inpatients, and critically ill patients. The patients' demographics and hemogram values on admission were recorded. The predictive accuracies of lymphocyte count, lymphocyte percentage, eosinophil count, and eosinophil percentage for predicting severity were determined using receiver operating characteristic curves. Logistic regression analysis was used to predict intensive care unit demand according to lymphocyte and eosinophil values.

RESULTS

Of the 5828 coronavirus disease 2019 patients, 4050 were followed up as outpatients, 1581 were hospitalized in a ward, and 197 were hospitalized in the intensive care unit. Lymphocyte count and lymphocyte percentage were significantly different between the groups, but the difference for eosinophil count and eosinophil percentage was not significant as it was for lymphocytes. Cutoff values for lymphocyte count (1.0 × 109 /L), lymphocyte percentage (22%), eosinophil count (0.052 × 109 /L), and eosinophil percentage (0.08%) were found to indicate a high risk for intensive care unit admission. Coronavirus disease 2019 patients >55 years of age, with a lymphocyte count <1.0 × 109 /L, a lymphocyte percentage <22%, and an eosinophil percentage <0.08% had a 2-fold higher risk of requiring intensive care unit management.

CONCLUSION

Lymphocyte counts and percentages are quick and reliable biomarkers for predicting coronavirus disease 2019 severity and may guide physicians for proper management earlier.

SARS-CoV-2 Infection Dysregulates Host Iron (Fe)-Redox Homeostasis (Fe-R-H): Role of Fe-Redox Regulators, Ferroptosis Inhibitors, Anticoagulants, and Iron-Chelators in COVID-19 Control

Severe imbalance in iron metabolism among SARS-CoV-2 infected patients is prominent in every symptomatic (mild, moderate to severe) clinical phase of COVID-19. Phase-I - Hypoxia correlates with reduced O₂ transport by erythrocytes, overexpression of HIF-1α, altered mitochondrial bioenergetics with host metabolic reprogramming (HMR). Phase-II - Hyperferritinemia results from an increased iron overload, which triggers a fulminant proinflammatory response - the acute cytokine release syndrome (CRS). Elevated cytokine levels (i.e. IL6, TNFα and CRP) strongly correlates with altered ferritin/TF ratios in COVID-19 patients. Phase-III - Thromboembolism is consequential to erythrocyte dysfunction with heme release, increased prothrombin time and elevated D-dimers, cumulatively linked to severe coagulopathies with life-threatening outcomes such as ARDS, and multi-organ failure. Taken together, Fe-R-H dysregulation is implicated in every symptomatic phase of COVID-19. Fe-R-H regulators such as lactoferrin (LF), hemoxygenase-1 (HO-1), erythropoietin (EPO) and hepcidin modulators are innate bio-replenishments that sequester iron, neutralize iron-mediated free radicals, reduce oxidative stress, and improve host defense by optimizing iron metabolism. Due to its pivotal role in 'cytokine storm', ferroptosis is a potential intervention target. Ferroptosis inhibitors such as ferrostatin-1, liproxstatin-1, quercetin, and melatonin could prevent mitochondrial lipid peroxidation, up-regulate antioxidant/GSH levels and abrogate iron overload-induced apoptosis through activation of Nrf2 and HO-1 signaling pathways. Iron chelators such as heparin, deferoxamine, caffeic acid, curcumin, α-lipoic acid, and phytic acid could protect against ferroptosis and restore mitochondrial function, iron-redox potential, and rebalance Fe-R-H status. Therefore, Fe-R-H restoration is a host biomarker-driven potential combat strategy for an effective clinical and post-recovery management of COVID-19.

[Clinical features of 19 children infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 in Hangzhou, China]

OBJECTIVES

To study the clinical features of children infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

The medical data of 19 children who were diagnosed with SARS-CoV-2 Omicron variant infection from January 28 to March 3, 2022 in Hangzhou were retrospectively reviewed.

RESULTS

Among the 19 children, there were 7 boys (37%) and 12 girls (63%), and their age ranged from 6 months to 16 years, with a median age of 2 years and 1 month. Most of these children were infants and young children (aged ≤3 years, accounting for 53%). Among these children, 11 (58%) were unvaccinated with SARS-CoV-2 vaccine and 8 (42%) were vaccinated with SARS-CoV-2 vaccine, and 3 children (16%) had a history of underlying diseases. All 19 children had a clear history of close contact with persons infected with SARS-CoV-2, and 10 children (53%) were involved in the cluster outbreak in a maternal and infant care center. In terms of clinical classification, 13 children (68%) had mild coronavirus disease 2019 (COVID-19) and 6 (32%) had common COVID-19, with no severe cases of COVID-19. The most common clinical symptoms were cough (100%) and fever (63%). The children with a normal peripheral white blood cell count accounted for 84%, and those with a normal lymphocyte count accounted for 68%. There were no significant abnormalities in platelet count, procalcitonin, liver function parameters (alanine aminotransferase and aspartate aminotransferase), and renal function parameters (creatinine and urea). Six children (32%) had obvious signs of pneumonia on chest CT. All 19 children were given symptomatic treatment, and 12 children (63%) were given aerosol inhalation of interferon α. All children were cured and discharged.

CONCLUSIONS

Children infected with Omicron variant strains are more common in infants and young children, with mild symptoms and good prognosis. Most of the children have a history of close contact with persons infected with SARS-CoV-2, and epidemic prevention and control should be strengthened in places with many infants and children, such as maternal and infant care centers.

D-dimer levels and characteristics of lymphocyte subsets, cytokine profiles in peripheral blood of patients with severe COVID-19: A systematic review and meta-analysis

Purpose

A series of complications caused by severe COVID-19 can significantly affect short-term results. Therefore, early diagnosis is essential for critically COVID-19 patients. we aimed to investigate the correlation among D-dimer levels, lymphocyte subsets, cytokines, and disease severity in COVID-19 patients.

Methods

Systematic review and meta- analysis of PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, Embase, clinical trials, and China National Knowledge Infrastructure (CNKI) until 1 August 2022. We considered case-control, and cohort studies that compared laboratory parameters between patients with severe or non-serious diseases or between survivors and non-survivors. Pooled data was assessed by use of a random-effects model and used I 2 to test heterogeneity. We assessed the risk of bias using the Newcastle- Ottawa Scale.

Results

Of the 5,561 identified studies, 32 were eligible and included in our analysis (N = 3,337 participants). Random-effect results indicated that patients with COVID-19 in severe group had higher levels for D-dimer (WMD = 1.217 mg/L, 95%CI=[0.788, 1.646], P < 0.001), neutrophil-to-lymphocyte ratio (NLR) (WMD = 6.939, 95%CI = [4.581, 9.297], P < 0.001), IL-2 (WMD = 0.371 pg/ml, 95%CI = [-0.190, 0.932], P = 0.004), IL-4 (WMD = 0.139 pg/ml, 95%CI = [0.060, 0.219], P = 0.717), IL-6 (WMD = 44.251 pg/ml, 95%CI = [27.010, 61.493], P < 0.001), IL-10 (WMD = 3.718 pg/ml, 95%CI = [2.648, 4.788], P < 0.001) as well as lower levels of lymphocytes (WMD = -0.468( × 109/L), 95%CI = [-0.543, -0.394], P < 0.001), T cells (WMD = -446.746(/μL), 95%CI = [-619.607, -273.885], P < 0.001), B cells (WMD = -60.616(/μL), 95%CI = [-96.452, -24.780], P < 0.001), NK cells (WMD = -68.297(/μL), 95%CI = [-90.600, -45.994], P < 0.001), CD3+T cells (WMD = -487.870(/μL), 95%CI = [-627.248, -348.492], P < 0.001), CD4+T cells (WMD = -290.134(/μL), 95%CI = [-370.834, -209.435], P < 0.001), CD8+T cells (WMD = -188.781(/μL), 95%CI = [-227.806, -149.757], P < 0.001).

Conclusions

There is a correlation among higher levels of D-dimer, cytokines, lower levels of lymphocyte subsets, and disease severity in COVID-19 patients. These effective biomarkers may help clinicians to evaluate the severity and prognosis of COVID-19. This study is registered with PROSPERO, number CRD42020196659.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=196659; PROSPERO registration number: CRD42020196659.

Lactate Dehydrogenase to Albumin ratio as a Predictive Factor of COVID-19 Patients' Outcome; a Cross-sectional Study

INTRODUCTION

 Despite the increasing vaccination coverage, COVID-19 is still a concern. With the limited health care capacity, early risk stratification is crucial to identify patients who should be prioritized for optimal management. The present study investigates whether on-admission lactate dehydrogenase to albumin ratio (LAR) can be used to predict COVID-19 outcomes.

METHODS

This retrospective cross-sectional study evaluated hospitalized COVID-19 patients in an academic referral center in Iran from May 2020 to October 2020. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the value of LAR in the prediction of mortality. The Yuden index was used to find the optimal cut-off of LAR to distinguish severity. Patients were classified into three groups (LAR tertiles), first: LAR<101.46, second: 101.46≤LAR< 148.78, and third group: LAR≥148.78. Logistic regression analysis was used to identify the association between tertiles of LAR, as well as the relationship between each one-unit increase in LAR with mortality and ICU admission in three models, based on potential confounding variables.

RESULTS

A total of 477 patients were included. Among all patients, 100 patients (21%) died, and 121 patients (25.4%) were admitted to intensive care unit (ICU). In the third group, the risk of mortality and ICU admission increased 7.78 times (OR=7.78, CI: 3.95-15.26; p <0.0001) and 4.49 times (OR=4.49, CI: 2.01-9.04; p <0.0001), respectively, compared to the first group. The AUC of LAR for prediction of mortality was 0.768 (95% CI 0.69- 0.81). LAR ≥ 136, with the sensitivity and specificity of 72% (95%CI: 62.1-80.5) and 70% (95%CI: 64.9-74.4), respectively, was the optimal cut-off value for predicting mortality.

CONCLUSION

High LAR was associated with higher odds of COVID-19 mortality, ICU admission, and length of hospitalization. On-admission LAR levels might help health care workers identify critical patients early on.

Cytokine Storm Signature in Patients with Moderate and Severe COVID-19

Hypercytokinemia, found in SARS-CoV-2 infection, contributes to multiple organ dysfunctions with acute respiratory distress syndrome, shock etc. The aim of this study was to describe cytokine storm signatures in patients with acute COVID-19 and to investigate their influence on severity of the infection. Plasma levels of 47 cytokines were investigated in 73 patients with moderate and severe COVID-19 (41 and 32, respectively) and 11 healthy donors (HD). The most elevated levels comparing patients and the HD were observed for seven pro-inflammatory cytokines (IL-6, IL-8, IL-15, IL-18, IL-27, IFNγ, TNFα), three chemokines (GROα, IP-10, MIG), two anti-inflammatory cytokines (IL-1RA, IL-10), and two growth factors (G-CSF, M-CSF). The patients with severe disease had significantly higher levels of FGF-2/FGF-basic, IL-1β, and IL-7 compared to the HD. The two groups of patients differed from each other only based on the levels of EGF, eotaxin, and IL-12 p40. Pneumonia lung injury, characterized by computer tomography, positively correlated with levels of EGF, IP-10, MCP-3 levels and negatively with IL-12 p40. Pro-inflammatory factors including IL-6, TNFα, and IP-10 negatively correlated with the frequency of the circulating T-helper17-like cells (Th17-like) and follicular Th cells that are crucial to develop SARS-CoV-2-specific plasma cells and memory B cells. Obtained data on the cytokine levels illustrate their influence on progression and severity of COVID-19.

Red Blood Cell Morphologic Abnormalities in Patients Hospitalized for COVID-19

Peripheral blood smear is a simple laboratory tool, which remains of invaluable help for diagnosing primary and secondary abnormalities of blood cells despite advances in automated and molecular techniques. Red blood cells (RBCs) abnormalities are known to occur in many viral infections, typically in the form of mild normo-microcytic anemia. While several hematological alterations at automated complete blood count (including neutrophilia, lymphopenia, and increased red cell distribution width—RDW) have been consistently associated with severity of COVID-19, there is scarce information on RBCs morphological abnormalities, mainly as case-reports or small series of patients, which are hardly comparable due to heterogeneity in sampling times and definition of illness severity. We report here a systematic evaluation of RBCs morphology at peripheral blood smear in COVID-19 patients within the first 72 h from hospital admission. One hundred and fifteen patients were included, with detailed collection of other clinical variables and follow-up. A certain degree of abnormalities in RBCs morphology was observed in 75 (65%) patients. Heterogenous alterations were noted, with spiculated cells being the more frequent morphology. The group with &gt;10% RBCs abnormalities had more consistent lymphopenia and thrombocytopenia compared to those without abnormalities or &lt;10% RBCs abnormalities (p &lt; 0.018, and p &lt; 0.021, respectively), thus underpinning a possible association with an overall more sustained immune-inflammatory “stress” hematopoiesis. Follow-up analysis showed a different mortality rate across groups, with the highest rate in those with more frequent RBCs morphological alterations compared to those with &lt;10% or no abnormalities (41.9%, vs. 20.5%, vs. 12.5%, respectively, p = 0.012). Despite the inherent limitations of such simple association, our results point out towards further studies on erythropoiesis alterations in the pathophysiology of COVID-19.

Dysregulated Immune Responses in SARS-CoV-2-Infected Patients: A Comprehensive Overview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first detected in humans more than two years ago and caused an unprecedented socio-economic burden on all countries around the world. Since then, numerous studies have attempted to identify various mechanisms involved in the alterations of innate and adaptive immunity in COVID-19 patients, with the ultimate goal of finding ways to correct pathological changes and improve disease outcomes. State-of-the-art research methods made it possible to establish precise molecular mechanisms which the new virus uses to trigger multisystem inflammatory syndrome and evade host antiviral immune responses. In this review, we present a comprehensive analysis of published data that provide insight into pathological changes in T and B cell subsets and their phenotypes, accompanying the acute phase of the SARS-CoV-2 infection. This knowledge might help reveal new biomarkers that can be utilized to recognize case severity early as well as to provide additional objective information on the effective formation of SARS-CoV-2-specific immunity and predict long-term complications of COVID-19, including a large variety of symptoms termed the 'post-COVID-19 syndrome'.

Covid-19 hastalarının kan gazı ölçümleri ve hematolojik manifestasyonlarının mortalite ile ilişkisi: Retrospektif analiz

Abstract Objective: The aim was to investigate the relationship between blood gas and complete blood count parameters and mortality in patients with Covid-19 during and after in the intensive care unit (ICU). Material and Methods: Patients were divided as group nonsurvivor and group survivor. Hematological parameters were registered on the day 1, 3, 5. Results: A total of 142 patients were analyzed retrospectively in the study. Out of them, 46 were women (32%). Seventy-one patients were in group nonsurvivor (50%). The median age of group nonsurvivor patients was 61 years, and the median age of group survivor patients was 60 years. Noninvasive ventilation day and mechanical ventilation day were higher in group nonsurvivor. In group nonsurviver, at the admission to the ICU, in the third day and in the fifth day of ICU, PO2/FiO2 (p

Progress and Challenges Toward Generation and Maintenance of Long-Lived Memory T Lymphocyte Responses During COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) pandemic is a serious global threat until we identify the effective preventive and therapeutic strategies. SARS-CoV-2 infection is characterized by various immunopathological consequences including lymphocyte activation and dysfunction, lymphopenia, cytokine storm, increased level of neutrophils, and depletion and exhaustion of lymphocytes. Considering the low level of antibody-mediated protection during coronavirus infection, understanding the role of T cell for long-term protection is decisive. Both CD4⁺ and CD8⁺ T cell response is imperative for cell-mediated immune response during COVID-19. However, the level of CD8⁺ T cell response reduced to almost half as compared to CD4⁺ after 6 months of infection. The long-term protection is mediated via generation of immunological memory response during COVID-19. The presence of memory CD4⁺ T cells in all the severely infected and recovered individuals shows that the memory response is predominated by CD4⁺ T cells. Prominently, the antigen-specific CD4⁺ and CD8⁺ T cells are specifically observed during day 0 to day 28 in COVID-19-vaccinated individuals. However, level of antigen-specific T memory cells in COVID-19-vaccinated individuals defines the long-term protection against forthcoming outbreaks of SARS-CoV-2.

Obesity or increased body mass index and the risk of severe outcomes in patients with COVID-19: A protocol for systematic review and meta-analysis

BACKGROUND

To assess the effect of obesity or a high body mass index (BMI) on the risk of severe outcomes in patients with coronavirus disease 2019 (COVID-19).

METHODS

Studies on the relationship between BMI or obesity and COVID-19 since December 2019. The odds ratio (OR) and weighted mean difference (WMD) with their 95% confidence intervals (CIs) were used to assess the effect size.

RESULTS

BMI was significantly increased in COVID-19 patients with severe illness (WMD: 1.18; 95% CI: 0.42-1.93), who were admitted to an intensive care unit (ICU) (WMD: 1.46; 95% CI: 0.96-1.97), who required invasive mechanical ventilation (IMV) (WMD: 2.70, 95% CI: 1.05-4.35) and who died (WMD: 0.91, 95% CI: 0.02-1.80). In Western countries, obesity (BMI of ≥30 kg/m2) increased the risk of hospitalization (OR: 2.08; 95% CI: 1.22-3.54), admission to an ICU (OR: 1.54; 95% CI: 1.29-1.84), need for IMV (OR: 1.73, 95% CI: 1.38-2.17), and mortality (OR: 1.43; 95% CI: 1.17-1.74) of patients with COVID-19. In the Asian population, obesity (BMI of ≥28 kg/m2) increased the risk of severe illness (OR: 3.14; 95% CI: 1.83-5.38). Compared with patients with COVID-19 and a BMI of <25 kg/m2, those with a BMI of 25-30 kg/m2 and ≥30 kg/m2 had a higher risk of need for IMV (OR: 2.19, 95% CI: 1.30-3.69 and OR: 3.04; 95% CI: 1.76-5.28, respectively). The risk of ICU admission in patients with COVID-19 and a BMI of ≥30 kg/m2 was significantly higher than in those with a BMI of 25-30 kg/m2 (OR: 1.49; 95% CI: 1.00-2.21).

CONCLUSION

As BMI increased, the risks of hospitalization, ICU admission, and need for IMV increased, especially in COVID-19 patients with obesity.

ETHICS AND DISSEMINATION

This systematic review and meta-analysis does not require an ethics approval as it does not collect any primary data from patients.

The role of laboratory biomarkers in diagnostics and management of COVID-19 patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a highly transmittable and heterogenic infection of the respiratory tract, characterized by a broad spectrum of clinical manifestations with a different degree of severity. Medical laboratories play an important role in early diagnosis and management of Coronavirus Disease 2019 (COVID-19) patients. Indeed, the results of several laboratory tests are essential for assessing the severity of the disease, selecting appropriate therapeutic procedures and monitoring treatment response. Routine laboratory testing in COVID-19 patients includes biomarkers of acute phase reaction, hematological and biochemical parameters that indicate tissue injury. The aim of this review paper is to describe the role of these biomarkers in the diagnostics and management of adult and pediatric COVID-19 patients.

S, Kumar T, Bharti S, Bhadani PP. Association of Peripheral Blood Parameters With Outcomes of COVID-19 Infection in a Tertiary Care Setting of Eastern India: An Institute-Based Study

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the Coronavirus DISEASE 2019 (COVID-19) pandemic. Blood investigations play a vital role in providing information regarding the inflammatory process. Previous studies have shown that complete blood count parameters have clinical importance in predicting disease outcomes. However, there is a scarcity of literature published from our region in India.

Aims

The present study was conducted to describe the epidemiological, clinical, and hematological characteristics and outcomes of COVID-19 confirmed cases.

Material and methods

All real-time reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed SARS-CoV-2 cases admitted in our institute over three months, from July to September 2020, were included in the study population. The blood samples of SARS-CoV-2 positive cases were analyzed for complete blood counts and coagulation profile on admission and at the time of discharge (most recent in case of mortality).

Results

A total of 252 RT-PCR confirmed SARS-CoV-2 cases were included in the study. The most common age group affected was 46 to 60 years, and the male-to-female ratio was 2.45:1. The most common clinical symptom was dyspnea, and the commonest comorbidity was hypertension. The statistical analysis showed a significant association of age, absolute neutrophil count (ANC) D-dimer, neutrophil-to-lymphocyte ratio (NLR), and platelets-to-lymphocyte ratio (PLR) with intensive care unit (ICU) admission and death. Gender, dyspnea, and absolute eosinophil count (AEC) showed significant association with ICU patients only, while liver disease and absolute lymphocyte count (ALC) had a significant association with death.

Conclusion

There are many notable clinical and hematological manifestations of COVID-19. Age, gender, dyspnea, comorbid liver disease, ANC, ALC AEC, NLR, PLR, and D- dimer may help clinicians predict the disease progression and reduce mortality risk.

An overview of the recent findings of cell-based therapies for the treatment and management of COVID-19

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic taking the lives of millions. The virus itself not only invades and destroys the angiotensin-converting enzyme 2 (ACE2)-expressing cells of the lungs, kidneys, liver, etc. but also elicits a hyperinflammatory immune response, further damaging the tissue leading to acute respiratory distress syndrome (ARDS) and death. Although vaccines, as a prime example of active immunotherapy, have clearly disrupted the transmission of virus and reduced mortality, hospitalization, and burden of disease, other avenues of immunotherapy are also being explored. One such approach would be to adoptively transfer modified/unmodified immune cells to the critically ill. Here, we compiled and summarized the immunopathogenesis of SARS-CoV-2 and the recent preclinical and clinical data on the potential of cell-based therapies in the fight against COVID-19.

COVID-19-Associated Eosinopenia in a Patient With Chronic Eosinophilia Due to Chronic Strongyloidiasis

Eosinopenia was frequently encountered in patients with coronavirus disease 2019 (COVID-19). We describe a case of a 59-year-old man who was treated with high-dose corticosteroids and anti-interleukin 1 receptor antagonist therapy because of severe acute respiratory distress syndrome due to a so-called cytokine storm in COVID-19. He had chronic eosinophilia for many years due to an unknown Strongyloides stercoralis infection, proven by serology and a positive polymerase chain reaction test on a stool sample. COVID-19 led to a complete resolution of eosinophilia, even before immunosuppressive treatment was started. Eosinophilia returned after recovery from COVID-19 and started to decline under treatment with ivermectin. Our case confirms previous reports of eosinopenia in COVID-19, as it appears even in patients with chronic eosinophilia. Presence of eosinophilia should prompt screening for strongyloidiasis in all patients eligible for immunosuppressive therapy because of the risk of Strongyloides hyperinfection syndrome, especially if this treatment is empirical.

Risk-Assessment of Hospitalized Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infected Patients Using Laboratory Data and Immune Cell Morphological Assessment

CONTEXT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious agent, with the propensity to cause severe illness. While vaccine uptake has been increasing in recent months, many regions remain at risk of significant coronavirus disease 19 (COVID-19) related healthcare burden. Health systems will continue to benefit from the availability of a variety of clinical and laboratory model when other triaging models are equivocal.

OBJECTIVE

To validate previously reported clinical laboratory abnormalities seen in COVID-19 patients and identify what laboratory parameters might be outcome-predictive.

DESIGN

We undertook an observational study of hospital-admitted COVID-19 patients (n=113), looking at a broad selection of clinical, laboratory, peripheral blood smear, and outcome data over discrete discovery and validation periods from March 2020 to November 2020.

RESULTS

We confirmed the findings of previous studies noting derangement of a variety of laboratory parameters in COVID-19 patients, including peripheral blood morphological changes. We also devised a simple-to-use decision tree by which patients could be risk stratified on the basis of Red Blood Cell count, creatinine, urea, and atypical plasmacytoid lymphocyte ("covidocyte") count. This outcome classifier performed comparably to the World Health Organization clinical classifier and the neutrophil-lymphocyte ratio.

CONCLUSIONS

Our data add to the increasing number of studies cataloguing laboratory changes in COVID-19, and support the clinical utility of incorporating blood morphological assessment in the workup of hospitalized COVID-19 patients.

An immunogenetic view of COVID-19

Meeting the challenges brought by the COVID-19 pandemic requires an interdisciplinary approach. In this context, integrating knowledge of immune function with an understanding of how genetic variation influences the nature of immunity is a key challenge. Immunogenetics can help explain the heterogeneity of susceptibility and protection to the viral infection and disease progression. Here, we review the knowledge developed so far, discussing fundamental genes for triggering the innate and adaptive immune responses associated with a viral infection, especially with the SARS-CoV-2 mechanisms. We emphasize the role of the HLA and KIR genes, discussing what has been uncovered about their role in COVID-19 and addressing methodological challenges of studying these genes. Finally, we comment on questions that arise when studying admixed populations, highlighting the case of Brazil. We argue that the interplay between immunology and an understanding of genetic associations can provide an important contribution to our knowledge of COVID-19.

COVID-19 and Progesterone: Part 2. Unraveling High Severity, Immunity Patterns, Immunity grading, Progesterone and its potential clinical use

Severely ill COVID–19 (Corona Virus Disease of 2019) patients have a hyperinflammatory condition with a high concentration of pro-inflammatory cytokines termed the cytokine storm. This milieu is reported to cause acute lung injury, oxygen deprivation, multiorgan damage, critical illness, and often death. Post SARS–CoV–2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection, the fight between the invading virus and the host's immune system would either terminate in recovery, with eradication of the infection and regulation of the immune system; or there would be a continuation of immune attacks even after the virus has been cleared, leading to immune dysregulation and disease. This outcome is chiefly dependent on two factors: (1) the patient's immune response, and (2) sufficiency plus efficiency of the regulator(s). Concerning the first, the present research introduces a framework based on different types of immune responses to SARS–CoV–2 along with known disease examples, and how this relates to varying clinical outcomes and treatment needs for COVID–19 patients. About the second factor of ‘regulator(s)’, part 1 of the manuscript described in depth the regulatory role of progesterone in COVID–19. The present study investigates five immunity patterns and the status of the regulatory hormone progesterone with respect to the two established demographic risk factors for COVID–19 high-severity: male sex, and old age. The study evaluates the status of progesterone as a credible determinant of immune regulation and dysregulation. It duly relates the immunity patterns to clinical outcomes and evinces indications for clinical use of progesterone in COVID–19. It proposes a clear answer to the question: "why are males and old patients most likely to have critical illness due to COVID–19?" The study highlights clinical domains for the use of progesterone in COVID–19. Part 2 of this research introduces the concept of immunity patterns and immunity grading. These concepts herewith provided for the clinical course of COVID–19 also apply to other hyperinflammatory conditions. Possible clinical applications of progesterone to treat critically ill COVID–19 patients will open an avenue for hormonal treatments of infections and other immune-related diseases.

Associations of immunological features with COVID-19 severity: a systematic review and meta-analysis

BACKGROUND

COVID-19 has spread widely worldwide, causing millions of deaths. We aim to explore the association of immunological features with COVID-19 severity.

METHODS

We conducted a meta-analysis to estimate mean difference (MD) of immune cells and cytokines levels with COVID-19 severity in PubMed, Web of Science, Scopus, the Cochrane Library and the grey literature.

RESULTS

A total of 21 studies with 2033 COVID-19 patients were included. Compared with mild cases, severe cases showed significantly lower levels of immune cells including CD3⁺ T cell (× 10⁶, MD, - 413.87; 95%CI, - 611.39 to - 216.34), CD4⁺ T cell (× 10⁶, MD, - 203.56; 95%CI, - 277.94 to - 129.18), CD8⁺ T cell (× 10⁶, MD, - 128.88; 95%CI, - 163.97 to - 93.79), B cell (× 10⁶/L; MD, - 23.87; 95%CI, - 43.97 to - 3.78) and NK cell (× 10⁶/L; MD, - 57.12; 95%CI, - 81.18 to - 33.06), and significantly higher levels of cytokines including TNF-α (pg/ml; MD, 0.34; 95%CI, 0.09 to 0.59), IL-5 (pg/ml; MD, 14.2; 95%CI, 3.99 to 24.4), IL-6 (pg/ml; MD, 13.07; 95%CI, 9.80 to 16.35), and IL-10 (pg/ml; MD, 2.04; 95%CI, 1.32 to 2.75), and significantly higher levels of chemokines as MCP-1 (SMD, 3.41; 95%CI, 2.42 to 4.40), IP-10 (SMD, 2.82; 95%CI, 1.20 to 4.45) and eotaxin (SMD, 1.55; 95%CI, 0.05 to 3.05). However, no significant difference was found in other indicators such as Treg cell (× 10⁶, MD, - 0.13; 95%CI, - 1.40 to 1.14), CD4⁺/CD8⁺ ratio (MD, 0.26; 95%CI, - 0.02 to 0.55), IFN-γ (pg/ml; MD, 0.26; 95%CI, - 0.05 to 0.56), IL-2 (pg/ml; MD, 0.05; 95%CI, - 0.49 to 0.60), IL-4 (pg/ml; MD, - 0.03; 95%CI, - 0.68 to 0.62), GM-CSF (SMD, 0.44; 95%CI, - 0.46 to 1.35), and RANTES (SMD, 0.94; 95%CI, - 2.88 to 4.75).

CONCLUSION

Our meta-analysis revealed significantly lower levels of immune cells (CD3⁺ T, CD4⁺ T, CD8⁺ T, B and NK cells), higher levels of cytokines (TNF-α, IL-5, IL-6 and IL-10) and higher levels of chemokines (MCP-1, IP-10 and eotaxin) in severe cases in comparison to mild cases of COVID-19. Measurement of immunological features could help assess disease severity for effective triage of COVID-19 patients.

Various theranostics and immunization strategies based on nanotechnology against Covid-19 pandemic: An interdisciplinary view

COVID-19 pandemic is still a major risk to human civilization. Besides the global immunization policy, more than five lac new cases are documented everyday. Some countries newly implement partial/complete nationwid lockdown to mitigate recurrent community spreading. To avoid the new modified stain of SARS-CoV-2 spreading, some countries imposed any restriction on the movement of the citizens within or outside the country. Effective economical point of care diagnostic and therapeutic strategy is vigorously required to mitigate viral spread. Besides struggling with repurposed medicines, new engineered materials with multiple unique efficacies and specific antiviral potency against SARS-CoV-2 infection may be fruitful to save more lives. Nanotechnology-based engineering strategy sophisticated medicine with specific, effective and nonhazardous delivery mechanism for available repurposed antivirals as well as remedial for associated diseases due to malfeasance in immuno-system e.g. hypercytokinaemia, acute respiratory distress syndrome. This review will talk about gloomy but critical areas for nanoscientists to intervene and will showcase about the different laboratory diagnostic, prognostic strategies and their mode of actions. In addition, we speak about SARS-CoV-2 pathophysiology, pathogenicity and host specific interation with special emphasis on altered immuno-system and also perceptualized, copious ways to design prophylactic nanomedicines and next-generation vaccines based on recent findings.

Altered Blood Cell Traits Underlie a Major Genetic Locus of Severe COVID-19

Background

The genetic locus 3p21.31 has been associated with severe coronavirus disease 2019 (COVID-19), but the underlying pathophysiological mechanism is unknown.

Methods

To identify intermediate traits associated with the 3p21.31 locus, we first performed a phenome-wide association study (PheWAS) with 923 phenotypes in 310,999 European individuals from the UK Biobank. For genes potentially regulated by the COVID-19 risk variant, we examined associations between their expression and the polygenic score (PGS) of 1,263 complex traits in a meta-analysis of 31,684 blood samples. For the prioritized blood cell traits, we tested their associations with age and sex in the same UK Biobank sample.

Results

Our PheWAS highlighted multiple blood cell traits to be associated with the COVID-19 risk variant, including monocyte count and percentage (p = 1.07×10 ^-8, 4.09×10 ^-13), eosinophil count and percentage (p = 5.73×10 ^-3, 2.20×10 ^-3), and neutrophil percentage (p = 3.23×10 ^-3). The PGS analysis revealed positive associations between the expression of candidate genes and genetically predicted counts of specific blood cells: CCR3 with eosinophil and basophil (p = 5.73×10 ^-21, 5.08×10 ^-19); CCR2 with monocytes (p = 2.40×10 ^-10); and CCR1 with monocytes and neutrophil (p = 1.78×10 ^-6, 7.17×10 ^-5). Additionally, we found that almost all examined white blood cell traits are significantly different across age and sex groups.

Conclusions

Our findings suggest that altered blood cell traits, especially those of monocyte, eosinophil, and neutrophil, may represent the mechanistic links between the genetic locus 3p21.31 and severe COVID-19. They may also underlie the increased risk of severe COVID-19 in older adults and men.

Peripheral T cell lymphopenia in COVID-19: potential mechanisms and impact

Immunopathogenesis involving T lymphocytes, which play a key role in defence against viral infection, could contribute to the spectrum of COVID-19 disease and provide an avenue for treatment. To address this question, a review of clinical observational studies and autopsy data in English and Chinese languages was conducted with a search of registered clinical trials. Peripheral lymphopenia affecting CD4 and CD8 T cells was a striking feature of severe COVID-19 compared with non-severe disease. Autopsy data demonstrated infiltration of T cells into organs, particularly the lung. Seventy-four clinical trials are on-going that could target T cell-related pathogenesis, particularly IL-6 pathways. SARS-CoV-2 infection interrupts T cell circulation in patients with severe COVID-19. This could be due to redistribution of T cells into infected organs, activation induced exhaustion, apoptosis, or pyroptosis. Measuring T cell dynamics during COVID-19 will inform clinical risk-stratification of hospitalised patients and could identify those who would benefit most from treatments that target T cells.

Association between the peripheral blood eosinophil counts and COVID-19: A meta-analysis

BACKGROUND

The conclusions about the relationship between eosinophil counts and the severity of coronavirus disease 2019 (COVID-19) were controversial, so we updated the evidences and reassessed it.

METHODS

We searched the PubMed, Cochrane library, Excerpta Medica Database, and Web of Science to compare the eosinophil counts about non-severe disease group (mild pneumonia, moderate pneumonia, non-critical disease and recovery group) and severe disease group (severe pneumonia, critical pneumonia, critical disease and death group) in COVID-19.

RESULTS

A total of 1228 patients from 10 studies were included. Compared with non-severe group, severe group had strikingly lower average eosinophil counts (SMD 0.65, 95% confidence intervals [CI] 0.29-1.01; P < .001). The result of subgroup analysis of different countries showed SMD 0.66, 95% CI 0.26-1.06; P < .001. Another subgroup analysis between mild-moderate pneumonia versus severe-critical pneumonia showed SMD 0.69, 95% CI 0.25-1.13; P < .001, and no significant risk of publication bias (Begg test 0.063 and Egger test 0.057) in this subgroup. The heterogeneity was substantial, but the sensitivity analyses showed no significant change when individual study was excluded, which suggested the crediblity and stablity of our results.

CONCLUSIONS

The eosinophil counts had important value as an indicator of severity in patients with COVID-19.

PROSPERO REGISTRATION NUMBER

CRD42020205497.

Leukocyte differential and reactive lymphocyte counts from Sysmex XN analyzer in the evaluation of SARS-CoV-2 infection

BACKGROUND

Leukocyte differential present certain features in COVID 19 patients. RE-LYMP (reactive lymphocytes) is an extended inflammation parameter (EIP) reported by XN analyzer (Sysmex Corporation, Kobe, Japan) reflect the activation of lymphocytes triggered by infections. We aimed to assess the clinical utility of these parameters as biomarkers for the rapid detection of COVID 19.

METHODS

The study group included 200 COVID 19 and 167 patients with other infections at admission. Differences of leukocyte differential, neutrophil/lymphocyte ratio (NLR) and EIP among groups were assessed with the Kruskal-Wallis test; parameters statiscally different in the groups were tested with Receiver operating characteristic (ROC) curve analysis to assess their diagnostic performance in distinguishing SARS-CoV-2 infections. The reliability of the selected parameters was evaluated in a validation group of 347 patients (160 COVID 19 and 187 other infections).

RESULTS

NLR performed well to discard viral infections, area under curve (AUC) 0.988 (95%CI 0.973 - 0.991) and RE-LYMP was useful to distinguish COVID 19 and bacterial infections AUC 0.920 (95%CI 0.884 - 0.948); the two conditions NLR> 3.3 RE-LYMP> 0.6% was applied to the validation group and 153 out of 160 COVID 19 patients were correctly distinguished (95.6%).

CONCLUSIONS

Early diagnosis of SARS-CoV-2 infection is critical for better caring of patients and to reduce the threat of nosocomial infection for professionals. Leukocyte differential and RE-LYMPH could assist in a preliminary differential diagnosis of the disease.

Severe acute respiratory syndrome-coronavirus-2 spike (S) protein based vaccine candidates: State of the art and future prospects

Coronavirus disease 2019 (Covid-19) is caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) which is responsible for a global pandemic that started in late 2019 in Wuhan, China. To prevent the worldwide spread of this highly pathogenic virus, development of an effective and safe vaccine is urgently needed. The SARS-CoV-2 and SARS-CoV share a high degree of genetic and pathologic identity and share safety and immune-enhancement concerns regarding vaccine development. Prior animal studies with first generation (whole virus-based) preparations of SARS-CoV vaccines (inactivated and attenuated vaccine modalities) indicated the possibility of increased infectivity or eosinophilic infiltration by immunization. Therefore, development of second and third generation safer vaccines (by using modern vaccine platforms) is actively sought for this viral infection. The spike (S) protein of SARS-CoVs is the main determinant of cell entry and tropism and is responsible for facilitating zoonosis into humans and sustained person-to-person transmission. Furthermore, 'S' protein contains multiple neutralizing epitopes that play an essential role in the induction of neutralizing antibodies (nAbs) and protective immunity. Moreover, T-cell responses against the SARS-CoV-2 'S' protein have also been characterized that correlate to the IgG and IgA antibody titres in Covid-19 patients. Thus, S protein is an obvious candidate antigen for inclusion into vaccine platforms against SARS-CoV-2 viral infection. This manuscript reviews different characteristics of S protein, its potency and 'state of the art' of the vaccine development strategies and platforms using this antigen, for construction of a safe and effective SARS-CoV-2 vaccine.

Edible and Herbal Plants for the Prevention and Management of COVID-19

Background: The outbreak of the pandemic coronavirus disease 2019 (COVID-19) has now become a global pandemic spreading throughout the world. Unfortunately, due to the high infectiousness of the novel β-coronavirus, it is very likely to become an ordinary epidemic. The development of dietary supplements and functional foods might provide a strategy for the prevention and management of COVID-19.

Scope and Approach: A great diversity of potential edible and medicinal plants and/or natural compounds showed potential benefits in managing SARS, which may also combat COVID-19. Moreover, many plants and compounds have currently been proposed to be protective against COVID-19. This information is based on data-driven approaches and computational chemical biology techniques. In this study, we review promising candidates of edible and medicinal plants for the prevention and management of COVID-19. We primarily focus on analyzing their underlying mechanisms. We aim to identify dietary supplements and functional foods that assist in managing this epidemic.

Key findings and Conclusion: We infer that acetoside, glyasperin, isorhamnetin, and several flavonoid compounds may prevent and/or be effective in managing COVID-19 by targeting the viral infection, reducing the host cytokine storm, regulating the immune response, and providing organ protection. These bioactive dietary components (used either alone or in combination) might assist in the development of dietary supplements or functional foods for managing COVID-19.

Drug Repurposing for COVID-19 Treatment by Integrating Network Pharmacology and Transcriptomics

Since coronavirus disease 2019 (COVID-19) is a serious new worldwide public health crisis with significant morbidity and mortality, effective therapeutic treatments are urgently needed. Drug repurposing is an efficient and cost-effective strategy with minimum risk for identifying novel potential treatment options by repositioning therapies that were previously approved for other clinical outcomes. Here, we used an integrated network-based pharmacologic and transcriptomic approach to screen drug candidates novel for COVID-19 treatment. Network-based proximity scores were calculated to identify the drug-disease pharmacological effect between drug-target relationship modules and COVID-19 related genes. Gene set enrichment analysis (GSEA) was then performed to determine whether drug candidates influence the expression of COVID-19 related genes and examine the sensitivity of the repurposing drug treatment to peripheral immune cell types. Moreover, we used the complementary exposure model to recommend potential synergistic drug combinations. We identified 18 individual drug candidates including nicardipine, orantinib, tipifarnib and promethazine which have not previously been proposed as possible treatments for COVID-19. Additionally, 30 synergistic drug pairs were ultimately recommended including fostamatinib plus tretinoin and orantinib plus valproic acid. Differential expression genes of most repurposing drugs were enriched significantly in B cells. The findings may potentially accelerate the discovery and establishment of an effective therapeutic treatment plan for COVID-19 patients.

COVID-19 illness and autoimmune diseases: recent insights

BACKGROUND

The aim of this review is to explore whether patients with autoimmune diseases (AIDs) were at high risk of infection during the COVID-19 epidemic and how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic affected immune system.

METHODS

A systematic literature search was performed using the foreign databases (NCBI, web of science, EBSCO, ELSEVIER ScienceDirect) and Chinese databases (WanFang, CNKI (China National Knowledge Infrastructure), VIP, CBM) to locate all relevant publications (up to January 10, 2021). The search strategies used Medical Search Headings (MeSH) headings and keywords for "COVID-19" or "SARS-CoV-2" or "coronavirus" and "autoimmune disease".

RESULTS

This review evaluates the effect of SARS-CoV-2 on the immune system through ACE-2 receptor binding as the main pathway for cell attachment and invasion. It is speculated that SARS-COV-2 infection can activate lymphocytes and inflammatory response, which may play a role in the clinical onset of AIDs and also patients were treated with immunomodulatory drugs during COVID-19 outbreak. Preliminary studies suggested that the risk of developing severe forms of COVID-19 in patients with AIDs treated with immunomodulators or biologics might not increase. A large number of samples are needed for further verification, leading to an excessive immune response to external stimuli.

CONCLUSION

The relationship between autoimmune diseases and SARS-CoV-2 infection is complex. During the COVID-19 epidemic, individualized interventions for AIDs should be provided such as Internet-based service.

Clinical and hematologic presentations of adults with COVID-19 patients in Jeddah: A case control study

Background

Coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2), is associated with significant morbidity and mortality. The clinical features of COVID-19 were mentioned in previous studies. However, risk factors for COVID-19 are not fully recognized. The aim of this study is to characterize risk factors and clinical features of COVID-19 disease in Jeddah, Saudi Arabia.

Methods

A retrospective, chart-review, case-control study was conducted at King Abdulaziz University, Jeddah, Saudi Arabia. Demographic, clinical, radiological, and laboratory data on patients diagnosed between March 18 and May 18, 2020 were collected and analyzed.

Results

We reviewed medical records on 297 suspected cases of COVID-19. Of these, 175 (59%) tested positive for COVID-19 by polymerase chain reaction (PCR) and considered as cases, while 122 (41%) tested negative and considered as control. COVID-19 positive cases were more likely to be males, and non-health care providers. Hypertension (15%), diabetes (10%) and two or more concurrent comorbidities (54.4%) were more prevalent among COVID-19 patients. Patients presented with fever, cough, and loss of taste/smell were more likely to test positive for COVID-19 (P = 0.001, 0.008, 0.008; respectively). Radiological evidence of pneumonia was associated with confirmed COVID-19 disease (P = 0.001). Shortness of breath and gastrointestinal symptoms were not associated with the risk of COVID-19 at presentation. On admission, white blood cells, neutrophils, lymphocytes, eosinophils, basophils, and platelets were significantly lower among COVID-19 patients compared with controls. Surprisingly, D-Dimer levels were lower among COVID-19 positive patients when compared with controls.

Conclusion

Male gender, hypertension, and diabetes are the most commonly observed risk factors associated with COVID-19 disease in Jeddah, Saudi Arabia. COVID-19 patient had significantly lower lymphocyte and neutrophil counts.

Perspectives and Challenges in the Fight Against COVID-19: The Role of Genetic Variability

In the last year, the advent of the COVID-19 pandemic brought a new consideration for the multidisciplinary sciences. The unknown mechanisms of infection used by SARS-CoV-2 and the absence of effective antiviral pharmacological therapy, diagnosis methods, and vaccines evoked scientific efforts on the COVID-19 outcome. In general, COVID-19 clinical features are a result of local and systemic inflammatory processes that are enhanced by some preexistent comorbidities, such as diabetes, obesity, cardiovascular, and pulmonary diseases, and biological factors, like gender and age. However, the discrepancies in COVID-19 clinical signs observed among those patients lead to investigations about the critical factors that deeply influence disease severity and death. Herein, we present the viral infection mechanisms and its consequences after blocking the angiotensin-converting enzyme 2 (ACE2) axis in different tissues and the progression of inflammatory and immunological reactions, especially the influence of genetic features on those differential clinical responses. Furthermore, we discuss the role of genotype as an essential indicator of COVID-19 susceptibility, considering the expression profiles, polymorphisms, gene identification, and epigenetic modifications of viral entry factors and their recognition, as well as the infection effects on cell signaling molecule expression, which amplifies disease severity.

White Blood Cells and Severe COVID-19: A Mendelian Randomization Study

Increasing evidence shows that white blood cells are associated with the risk of coronavirus disease 2019 (COVID-19), but the direction and causality of this association are not clear. To evaluate the causal associations between various white blood cell traits and the COVID-19 susceptibility and severity, we conducted two-sample bidirectional Mendelian Randomization (MR) analyses with summary statistics from the largest and most recent genome-wide association studies. Our MR results indicated causal protective effects of higher basophil count, basophil percentage of white blood cells, and myeloid white blood cell count on severe COVID-19, with odds ratios (OR) per standard deviation increment of 0.75 (95% CI: 0.60-0.95), 0.70 (95% CI: 0.54-0.92), and 0.85 (95% CI: 0.73-0.98), respectively. Neither COVID-19 severity nor susceptibility was associated with white blood cell traits in our reverse MR results. Genetically predicted high basophil count, basophil percentage of white blood cells, and myeloid white blood cell count are associated with a lower risk of developing severe COVID-19. Individuals with a lower genetic capacity for basophils are likely at risk, while enhancing the production of basophils may be an effective therapeutic strategy.

Overview of the Haematological Effects of COVID-19 Infection

From its early origins, COVID-19 has spread extensively and was declared a global pandemic by the World Health Organization in March of 2020. Although initially thought to be predominantly a respiratory infection, more recent evidence points to a multisystem systemic disease which is associated with numerous haematological and immunological disturbances in addition to its other effects. Here we review the current knowledge on the haematological effects of COVID-19.

Impact of SARS-CoV-2 infection on the recovery of peripheral blood mononuclear cells by density gradient

SARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6-56.1, Welch's t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.

Immunological Characteristics of Non-Intensive Care Hospitalized COVID-19 Patients: A Preliminary Report

The outbreak of coronavirus disease 2019 (COVID-19) is posing a threat to global health. This disease has different clinical manifestations and different outcomes. The immune response to the novel 2019 coronavirus is complex and involves both innate and adaptive immunity. In this context, cell-mediated immunity plays a vital role in effective immunity against SARS-CoV-2. Significant differences have been observed when comparing severe and non-severe patients. Since these immunological characteristics have not been fully elucidated, we aimed to use cluster analysis to investigate the immune cell patterns in patients with COVID-19 who required hospitalization but not intensive care. We identified four clusters of different immunological patterns, the worst being characterized by total lymphocytes, T helper lymphocytes CD4⁺ (CD4⁺), T cytotoxic lymphocytes CD8⁺ (CD8⁺) and natural killer (NK) cells below the normal range, together with natural killer lymphocyte granzyme < 50% (NK granzyme⁺) and antibody-secreting plasma cells (ASCs) equal to 0 with fatal outcomes. In the worst group, 50% of patients died in the intensive care unit. Moreover, a negative trend was found among four groups regarding total lymphocytes, CD4⁺, CD8⁺ and B lymphocytes (p < 0.001, p < 0.005, p < 0.000, p < 0.044, respectively). This detailed analysis of immune changes may have prognostic value. It may provide a new perspective for identifying subsets of COVID-19 patients and selecting novel prospective treatment strategies. Notwithstanding these results, this is a preliminary report with a small sample size, and our data may not be generalizable. Further cohort studies with larger samples are necessary to quantify the prognostic value's weight, according to immunological changes in COVID-19 patients, for predicting prognoses and realizing improvements in clinical conditions.

Association of smoking history with severe and critical outcomes in COVID-19 patients: A systemic review and meta-analysis

Introduction

The highly infectious coronavirus disease 2019 (COVID-19) has now rapidly spread around the world. This meta-analysis was strictly focused on the influence of smoking history on the severe and critical outcomes on people with COVID-19 pneumonia.

Methods

A systematic literature search was conducted in eight online databases before 1 February 2021. All studies meeting our selection criteria were included and evaluated. Stata 14.0 software was used to analyze the data.

Results

A total of 109 articles involving 517,020 patients were included in this meta-analysis. A statistically significant association was discovered between smoking history and COVID-19 severity, the pooled OR was 1.55 (95%CI: 1.41-1.71). Smoking was significantly associated with the risk of admission to intensive care unit (ICU) (OR=1.73, 95%CI: 1.36-2.19), increased mortality (OR=1.58, 95%CI: 1.38-1.81), and critical diseases composite endpoints (OR=1.61, 95%CI: 1.35-1.93), whereas there was no relationship with mechanical ventilation. The pooled prevalence of smoking using the random effects model (REM) was 15% (95%CI: 14%-16%). Meta-regression analysis showed that age (P=0.004), hypertension (P=0.007), diabetes (P=0.029), chronic obstructive pulmonary disease (COPD) (P=0.001) were covariates that affect the association.

Conclusions

Smoking was associated with severe or critical outcomes and increased the risk of admission to ICU and mortality in COVID-19 patients, but not associated with mechanical ventilation. This association was more significant for former smokers than in current smokers. Current smokers also had a higher risk of developing severe COVID-19 compared with non-smokers. More detailed data, which are representative of more countries, are needed to confirm these preliminary findings.

Do Blood Eosinophils Predict in-Hospital Mortality or Severity of Disease in SARS-CoV-2 Infection? A Retrospective Multicenter Study

Introduction: Healthcare systems worldwide have been battling the ongoing COVID-19 pandemic. Eosinophils are multifunctional leukocytes implicated in the pathogenesis of several inflammatory processes including viral infections. We focus our study on the prognostic value of eosinopenia as a marker of disease severity and mortality in COVID-19 patients. Methods: Between 1 March and 30 April 2020, we conducted a multicenter and retrospective study on a cohort of COVID-19 patients (moderate or severe disease) who were hospitalized after presenting to the emergency department (ED). We led our study in six major hospitals of northeast France, one of the outbreak’s epicenters in Europe. Results: We have collected data from 1035 patients, with a confirmed diagnosis of COVID-19. More than three quarters of them (76.2%) presented a moderate form of the disease, while the remaining quarter (23.8%) presented a severe form requiring admission to the intensive care unit (ICU). Mean circulating eosinophils rate, at admission, varied according to disease severity (p < 0.001), yet it did not differ between survivors and non-survivors (p = 0.306). Extreme eosinopenia (=0/mm³) was predictive of severity (aOR = 1.77, p = 0.009); however, it was not predictive of mortality (aOR = 0.892, p = 0.696). The areas under the Receiver operating characteristics (ROC) curve were, respectively, 58.5% (CI95%: 55.3–61.7%) and 51.4% (CI95%: 46.8–56.1%) for the ability of circulating eosinophil rates to predict disease severity and mortality. Conclusion: Eosinopenia is very common and often profound in cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Eosinopenia was not a useful predictor of mortality; however, undetectable eosinophils (=0/mm³) were predictive of disease severity during the initial ED management.

Smoking and risk of negative outcomes among COVID-19 patients: A systematic review and meta-analysis

INTRODUCTION

COVID-19 has major effects on the clinical, humanistic and economic outcomes among patients, producing severe symptoms and death. Smoking has been reported as one of the factors that increases severity and mortality rate among COVID-19 patients. However, the effect of smoking on such medical outcomes is still controversial. This study conducted a comprehensive systematic review and meta-analysis (SR/MA) on the association between smoking and negative outcomes among COVID-19 patients.

METHODS

Electronic databases, including PubMed, EMBASE, Cochrane Library, Science Direct, Google Scholar, were systematically searched from the initiation of the database until 12 December 2020. All relevant studies about smoking and COVID-19 were screened using a set of inclusion and exclusion criteria. The Newcastle-Ottawa Scale was used to assess the methodological quality of eligible articles. Random meta-analyses were conducted to estimate odds ratios (ORs) with 95% confidence interval (CIs). Publication bias was assessed using the funnel plot, Begg's test and Egger's test.

RESULTS

A total of 1248 studies were retrieved and reviewed. A total of 40 studies were finally included for meta-analysis. Both current smoking and former smoking significantly increase the risk of disease severity (OR=1.58; 95% CI: 1.16-2.15, p=0.004; and OR=2.48; 95% CI: 1.64-3.77, p<0.001; respectively) with moderate appearance of heterogeneity. Similarly, current smoking and former smoking also significantly increase the risk of death (OR=1.35; 95% CI: 1.12-1.62, p=0.002; and OR=2.58; 95% CI: 2.15-3.09, p<0.001; respectively) with moderate appearance of heterogeneity. There was no evidence of publication bias, which was tested by the funnel plot, Begg's test and Egger's test.

CONCLUSIONS

Smoking, even current smoking or former smoking, significantly increases the risk of COVID-19 severity and death. Further causational studies on this association and ascertianing the underlying mechanisms of this relation is warranted.

Anemia in patients with Covid-19: pathogenesis and clinical significance

COVID-19 patients typically present with lower airway disease, although involvement of other organ systems is usually the rule. Hematological manifestations such as thrombocytopenia and reduced lymphocyte and eosinophil numbers are highly prevalent in COVID-19 and have prognostic significance. Few data, however, are available about the prevalence and significance of anemia in COVID-19. In an observational study, we investigated the prevalence, pathogenesis and clinical significance of anemia among 206 patients with COVID-19 at the time of their hospitalization in an Internal Medicine unit. The prevalence of anemia was 61% in COVID-19, compared with 45% in a control group of 71 patients with clinical and laboratory findings suggestive of COVID-19, but nasopharyngeal swab tests negative for SARS-CoV-2 RNA (p = 0.022). Mortality was higher in SARS-CoV-2 positive patients. In COVID-19, females had lower hemoglobin concentration than males and a higher prevalence of moderate/severe anemia (25% versus 13%, p = 0.032). In most cases, anemia was mild and due to inflammation, sometimes associated with iron and/or vitamin deficiencies. Determinants of hemoglobin concentration included: erythrocyte sedimentation rate, serum cholinesterase, ferritin and protein concentrations and number of chronic diseases affecting each patient. Hemoglobin concentration was not related to overall survival that was, on the contrary, influenced by red blood cell distribution width, age, lactate dehydrogenase and the ratio of arterial partial oxygen pressure to inspired oxygen fraction. In conclusion, our results highlight anemia as a common manifestation in COVID-19. Although anemia does not directly influence mortality, it usually affects elderly, frail patients and can negatively influence their quality of life.