Neutrophil-to-Lymphocyte Ratios Are Closely Associated With the Severity and Course of Non-mild COVID-19

Immunopathological markers and cell types linked to COVID-19 symptom manifestation

BACKGROUND

Numerous studies have investigated the molecular properties that contribute to the symptoms of COVID-19, such as the virus's genetic makeup, its replication mechanisms, and how it interacts with host cells. However, identifying the immunopathological properties, such as the immune system's response, cytokine levels, and the presence of specific biomarkers, that are associated with the severity of the infection remains crucial for developing effective treatments and preventions.

METHODS

We analyzed blood protein factor profiles from 420 individuals to identify features differentiating between test-negative healthy, asymptomatic, and symptomatic individuals using statistical comparison and the least absolute shrinkage and selection operator (i.e., LASSO) algorithm. Additionally, we examined single-cell RNA sequencing data from 141 individuals to identify specific cell types associated with the COVID-19 symptoms.

RESULTS

Healthy individuals who tested negative had distinct blood protein factor levels compared to asymptomatic individuals. We identified two key protein factors, Serpin A10 and Complement C9, that differentiate between asymptomatic and symptomatic patients. Symptomatic patients showed lower levels of CD4+ T naïve, CD4+ T effector & memory, and CD8+ T naïve cells, along with higher levels of CD14+ classical monocytes compared to asymptomatic patients. Additionally, CD16+ non-classical monocytes, major producers of C1QA/B/C, appeared to contribute to the observed Complement C9 levels.

CONCLUSIONS

These findings advance our understanding of the immunopathological mechanisms underlying COVID-19 and may inform the development of targeted therapies and preventative measures. Future research should focus on further elucidating these mechanisms and exploring their potential clinical applications in managing COVID-19 severity.

Neutrophil-to-lymphocyte ratio in community-acquired pneumonia: Diagnostic potential and its limitations in the COVID era

Objective

To determine the diagnostic potential of neutrophil-to-lymphocyte ratio (NLR) as a POC marker to discriminate tuberculous from non-tuberculous CAP and identify limitations if any at a tertiary care centre in Uttarakhand, India.

Methods

225 patients presenting with respiratory complaints were recruited from the General Medicine clinics and investigated. NLR was noted at onset and correlated with final diagnosis.

Results

NLR from both groups did not exhibit a statistically significant difference. The area under curve (AUC) exhibited an accuracy of 49.1% in differentiating tuberculous from non-tubercular CAP, and an anomalous effect of prior steroid exposure on NLR was noted as a limitation.

Conclusion

The disparity of our results from previous studies warranted a review of literature which rendered a significant limitation of NLR. The NLR is affected by catecholamines, which makes the marker unreliable in patients with exogenous steroid exposure. This was not noted in the previous studies. We presume indiscriminate steroid usage in the pandemic confounded our findings. We propose that this limitation be accounted for in future studies so that NLR's true utility may be identified.

Hematological parameters and their predictive value for assessing disease severity in laboratory-confirmed COVID-19 patients: a retrospective study

BACKGROUND

The coronavirus disease 19 (COVID-19) infection has spread globally and caused a substantial amount of mortality and morbidity. Early detection of severe infections will improve care and reduce deaths. The use of hematological parameters in predicting COVID-19 disease severity, patient outcomes, and early risk stratification is limited. Therefore, the study was aimed at determining hematological parameters and their predictive value for assessing disease severity in laboratory-confirmed COVID-19 patients in Northwest Ethiopia.

METHODS

A retrospective cross-sectional study was conducted at the University of Gondar comprehensive specialized hospital and Tibebe Ghion comprehensive specialized referral hospital on 253 patients diagnosed with COVID-19 and admitted between March 2021 and February 2022. Data were extracted, and entered into Epi-data 4.2.0.0, and analyzed using SPSS version 25 software. Hematological parameters were provided as the median and interquartile range (IQR). Categorical variables were represented by their frequency, and the χ2 test was applied to compare observed results with expected results. The receiver-operating curve (ROC) was used to establish the predictive value of hematological parameters for COVID-19 severity. A p-value < 0.05 was considered statistically significant.

RESULTS

On a total of 253 patients, there were 43.87% severe cases, with a mortality rate of 26.9%. The ROC analysis showed the optimal cutoff values for hematological parameters were ANC (3370), lymphocyte (680), NLR (9.34), PLR (290.77), platelets (332,000), and WBCs (4390.65). The area under the curve (AUC) values for NLR (0.679) and ANC (0.631) were high, with the highest sensitivity and specificity, and could potentially be used to predict COVID-19 severity.

CONCLUSION

This study proved that high NLR and high ANC have prognostic value for assessing disease severity in COVID-19. Thus, assessing and considering these hematological parameters when triaging COVID-19 patients may prevent complications and improve the patient's outcome.

Prolonged inflammation in patients hospitalized for coronavirus disease 2019 (COVID-19) resolves 2 years after infection

Long-term complications from coronavirus disease 2019 (COVID-19) are concerning, as survivors can develop subclinical multiorgan dysfunction. It is unknown if such complications are due to prolonged inflammation, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination may reduce sequela. We conducted a prospective longitudinal study on hospitalized patients over 24 months. Clinical symptoms were collected by self-reporting during follow-up, along with blood samples for quantification of inflammatory markers and immune cell frequencies. All patients were given one dose of mRNA vaccine at 12-16 months. Their immune profiles at 12 and 24 months were compared. Approximately 37% and 39% of our patients reported post-COVID-19 symptoms at 12 and 24 months, respectively. The proportion of symptomatic patients with more than one symptom decreased from 69% at 12 months to 56% at 24 months. Longitudinal cytokine profiling revealed a cluster of individuals with persistently high inflammatory cytokine levels 12 months after infection. Patients with prolonged inflammation showed elevated terminally differentiated memory T cells in their blood; 54% had symptoms at 12 months. The majority of inflammatory markers and dysregulated immune cells in vaccinated patients recovered to a healthy baseline at 24 months, even though symptoms persisted. Post-COVID-19 symptoms can linger for 2 years after the initial infection and are associated with prolonged inflammation. Prolonged inflammation in hospitalized patients resolves after 2 years. We define a set of analytes associated with persistent inflammation and presence of symptoms, which could be useful biomarkers for identifying and monitoring high-risk survivors.

Reduced IL-8 Secretion by NOD-like and Toll-like Receptors in Blood Cells from COVID-19 Patients

Severe inflammatory responses are associated with the misbalance of innate and adaptive immunity. TLRs, NLRs, and cytokine receptors play an important role in pathogen sensing and intracellular control, which remains unclear in COVID-19. This study aimed to evaluate IL-8 production in blood cells from COVID-19 patients in a two-week follow-up evaluation. Blood samples were taken at admission (t1) and after 14 days of hospitalization (t2). The functionality of TLR2, TLR4, TLR7/8, TLR9, NOD1, and NOD2 innate receptors and IL-12 and IFN-γ cytokine receptors was evaluated by whole blood stimulation with specific synthetic receptor agonists through the quantification of IL-8, TNF-α, or IFN-γ. At admission, ligand-dependent IL-8 secretion was 6.4, 13, and 2.5 times lower for TLR2, TLR4, and endosomal TLR7/8 receptors, respectively, in patients than in healthy controls. Additionally, IL-12 receptor-induced IFN-γ secretion was lower in COVID-19 patients than in healthy subjects. We evaluated the same parameters after 14 days and observed significantly higher responses for TLR2, TLR4, TLR7/8, TLR9, and NOD1, NOD2, and IFN-γ receptors. In conclusion, the low secretion of IL-8 through stimulation with agonists of TLR2, TLR4, TLR7/8, TLR9, and NOD2 at t1 suggests their possible contribution to immunosuppression following hyperinflammation in COVID-19 disease.

Efficacy of therapeutic plasma exchange in severe COVID-19 disease: A meta-analysis

BACKGROUND AND OBJECTIVES

Therapeutic plasma exchange (TPE) has been used in severe COVID-19 disease to eliminate the cytokine storm. This meta-analysis aims to assess the effectiveness of TPE in reducing mortality in severe COVID-19 disease compared to standard treatment.

MATERIALS AND METHODS

A comprehensive literature search was performed in PubMed, the Cochrane database and the International Clinical Trial Registry Platform (ICTRP). The random-effect model was used to calculate the risk ratio and standardized mean difference (SMD) as pooled effect size for the difference in mortality and length of the intensive care unit (ICU) stay. The risk of bias and publication bias were assessed in R version 4.1.0. The certainty of the evidence was calculated using the GradePro tool.

RESULTS

The database identified 382 participants from six studies, including one randomized control trial. Egger's test did not detect any publication bias (p = 0.178). The random model analysis for mortality evaluated a risk ratio of 0.38 (95% CI: 0.28-0.52) with a significant reduction in the TPE group. The certainty of the evidence was moderate, with a risk ratio of 0.34 (95% CI: 0.24-0.49). Length of ICU stays between TPE versus standard care showed an SMD of 0.08 (95% CI: -0.38, 0.55) and was not significant.

CONCLUSION

The length of ICU stay in the TPE group was not different from standard care. However, this meta-analysis revealed a significant benefit of TPE in reducing mortality in severe COVID-19 disease compared to standard treatment.

Oxidative DNA Damage-induced PARP-1-mediated Autophagic Flux Disruption Contributes to Bupivacaine-induced Neurotoxicity During Pregnancy

OBJECTIVE

Severe neurologic complications after spinal anesthesia are rare but highly distressing, especially in pregnant women. Bupivacaine is widely used in spinal anesthesia, but its neurotoxic effects have gained attention.

METHODS

Furthermore, the etiology of bupivacaine-mediated neurotoxicity in obstetric patients remains unclear. Female C57BL/6 mice were intrathecally injected with 0.75% bupivacaine on the 18th day of pregnancy. We used immunohistochemistry to examine DNA damage after bupivacaine treatment in pregnant mice and measured γ-H2AX (Ser139) and 8-OHdG in the spinal cord. A PARP-1 inhibitor (PJ34) and autophagy inhibitor (3-MA) were administered with bupivacaine in pregnant mice. Parp-1flox/flox mice were crossed with Nes-Cre transgenic mice to obtain neuronal conditional knockdown mice. Then, LC3B and P62 staining were performed to evaluate autophagic flux in the spinal cords of pregnant wild-type (WT) and Parp-1-/- mice. We performed transmission electron microscopy (TEM) to evaluate autophagosomes.

RESULTS

The present study showed that oxidative stress-mediated DNA damage and neuronal injury were increased after bupivacaine treatment in the spinal cords of pregnant mice. Moreover, PARP-1 was significantly activated, and autophagic flux was disrupted. Further studies revealed that PARP-1 knockdown and autophagy inhibitors could alleviate bupivacaine-mediated neurotoxicity in pregnant mice.

CONCLUSION

Bupivacaine may cause neuronal DNA damage and PARP-1 activation in pregnant mice. PARP-1 further obstructed autophagic flux and ultimately led to neurotoxicity.

The Connection between Gut and Lung Microbiota, Mast Cells, Platelets and SARS-CoV-2 in the Elderly Patient

The human coronavirus SARS-CoV-2 or COVID-19 that emerged in late 2019 causes a respiratory tract infection and has currently resulted in more than 627 million confirmed cases and over 6.58 million deaths worldwide up to October 2022. The highest death rate caused by COVID-19 is in older people, especially those with comorbidities. This evidence presents a challenge for biomedical research on aging and also identifies some key players in inflammation, including mast cells and platelets, which could represent important markers and, at the same time, unconventional therapeutic targets. Studies have shown a decrease in the diversity of gut microbiota composition in the elderly, particularly a reduced abundance of butyrate-producing species, and COVID-19 patients manifest faecal microbiome alterations, with an increase in opportunistic pathogens and a depletion of commensal beneficial microorganisms. The main purpose of this narrative review is to highlight how an altered condition of the gut microbiota, especially in the elderly, could be an important factor and have a strong impact in the lung homeostasis and COVID-19 phenomenon, jointly to the activation of mast cells and platelets, and also affect the outcomes of the pathology. Therefore, a targeted and careful control of the intestinal microbiota could represent a complementary intervention to be implemented for the management and the challenge against COVID-19.

Neutrophilic inflammation promotes SARS-CoV-2 infectivity and augments the inflammatory responses in airway epithelial cells

In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre-existing co- morbidities correlating to incidence of severe COVID-19 are associated with chronic airway neutrophilia. Furthermore, examination of COVID-19 explanted lung tissue revealed a series of epithelial pathologies associated with the infiltration and activation of neutrophils, indicating neutrophil activity in response to SARS- CoV-2 infection. To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory responses to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. SARS-CoV-2 infection of the airway epithelium alone does not result in a notable pro-inflammatory response from the epithelium. The addition of neutrophils induces the release of proinflammatory cytokines and stimulates a significantly augmented pro-inflammatory response subsequent SARS-CoV-2 infection. The resulting inflammatory response is polarized with differential release from the apical and basolateral side of the epithelium. Additionally, the integrity of the epithelial barrier is impaired with notable epithelial damage and infection of basal stem cells. This study reveals a key role for neutrophil-epithelial interactions in determining inflammation and infectivity in response to SARS-CoV-2 infection.

A clinico-pathological study of COVID-19 associated rhino-orbital-cerebral mucormycosis

Purpose

Known predisposing factors for mucormycosis are neutropenia and diabetes. Though COVID-19 is associated with hyperinflammatory response, a high surge in rhino-orbital-cerebral mucormycosis (ROCM) cases was observed during the second wave. The histopathological features reflect the background pathogenesis. This study analyzes the histopathological features and clinical presentation of COVID-19-associated ROCM.

Methods

In this retrospective observational study, the clinical details of 89 proven ROCM patients treated during May-July 2021 were collected from the case records. Histopathological features were correlated with clinical staging groups and outcomes. The mean neutrophil-to-lymphocyte ratio (NLR) of clinical and outcome groups were compared.

Results

The mean age was 54.71 ± 11.03 years, with male patients constituting a majority (78.7%). Uncontrolled diabetes mellitus was noted in 70.8% of patients, and 3.4% had normal range of blood sugar. The mean blood sugar was 298.08 ± 99.51 mg/dL. The mean duration of onset of symptoms of mucormycosis from the diagnosis of COVID-19 was 17.36 ± 7.392 (3-45) days. Poor outcome with disease progression or death occurred in 21.3% of patients. Clinical group II patients (44.9%) with ROCM stages 3c and above had poor outcomes (P = 0.005). Histopathological analysis showed minimal inflammation in 25.8%, neutrophil extracellular trap (NET) in 75.3%, and angio-invasion in 28.1% of patients. Minimal inflammation was associated with clinical group II (P = 0.004) and poor outcome (P = 0.001). Angio-invasion correlated with poor outcome (P = 0.007). Patients with severe clinical group and poor outcome had higher mean NLR with P = 0.017 and P = 0.007, respectively.

Conclusion

Vision loss and cerebral involvement had poor outcomes. The histopathologic features such as inflammation and angio-invasion along with NLR aid as prognostic indicators in the management of ROCM. The role of NET in the pathogenesis of COVID-19-associated ROCM needs further studies.

Elevated Liver Enzymes along with Comorbidity Is a High Risk Factor for COVID-19 Mortality: A South Indian Study on 1,512 Patients

BACKGROUND AND AIMS

Liver enzyme abnormalities in coronavirus 2019 (COVID-19) are being addressed in the literature. The predictive risk of elevated liver enzymes has not been established for COVID-19 mortality. In this study, we hypothesized that elevated liver enzymes at admission can predict the outcome of COVID-19 disease with other known indicators, such as comorbidities.

METHODS

This retrospective study included all the consecutive hospitalized patients with confirmed COVID-19 disease from March 4^th to May 31^st, 2020. The study was conducted in Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu, India. We assessed demography, clinical variables, COVID-19 severity, laboratory parameters, and outcome.

RESULTS

We included 1,512 patients, and median age was 47 years (interquartile range: 34-60) with 36.9% being female. Liver enzyme level (aspartate aminotransferase and/or alanine aminotransferase) was elevated in 450/1,512 (29.76%) patients. Comorbidity was present in 713/1,512 (47.16%) patients. Patients with liver enzymes' elevation and presence of comorbidity were older, more frequently hospitalized in ICU and had more severe symptoms of COVID-19 at the time of admission. Presence of liver enzymes' elevation with comorbidity was a high risk factor for death (OR: 5.314, 95% CI: 2.278-12.393), as compared to patients with presence of comorbidity (OR: 4.096, 95% CI: 1.833-9.157).

CONCLUSIONS

Comorbidity combined with liver enzymes' elevation at presentation independently increased the risk of death in COVID-19 by at least 5-fold.

Long-Term Persistence of Anti-SARS-COV-2 IgG Antibodies

Antibodies against severe acute respiratory syndrome coronavirus-2 (Anti-SARS-COV-2) can be detected in patients with COVID-19 in 7 to 10 days post onset of symptoms (POS). However, there is no firm evidence of the long-term persistence of these antibodies in recovered COVID-19 patients. Therefore, this study aimed to evaluate the stability of anti-SARS-COV-2 IgG in recovered COVID-19 patients in a 15-month follow-up testing. Thirty hospitalized patients with real-time PCR-confirmed SARS-COV-2 infections were included in the study and five serum samples (1st, 2nd, 3rd, 4th, and 5th) were collected from each participant. The serum levels of N and S specific anti-SARS-COV-2 IgG and IgM antibodies were evaluated by the immunoassay technique at the same time. To determine the correlation between levels of anti-SARS-CoV-2 IgG/IgM with severity of disease, neutrophil-to-lymphocyte ratio (NLR %), and the serum levels of C-reactive protein were evaluated using an automated analyzer and turbidimetry assays, respectively. The mean serum level of anti-SARS-CoV-2 IgG antibody was at the highest level up to 90 days and then decreased significantly 1 year POS (P < 0.0001). However, it was still detectable in a 15-month follow-up testing. There were no significant differences in the mean levels of IgG antibody in patients with mild, moderate, and severe diseases. The results from this study suggest that the titer of anti-SARS-COV-2 IgG antibody is detectable at high levels up to 3 months and then decreases over time. However, these antibodies can be reliably detected in up to 15 months, and they may persist for a long time.

Communication Pattern Changes Along With Declined IGF1 of Immune Cells in COVID-19 Patients During Disease Progression

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19) pandemic, represents a global crisis. Most patients developed mild/moderate symptoms, and the status of immune system varied in acute and regulatory stages. The crosstalk between immune cells and the dynamic changes of immune cell contact is rarely described. Here, we analyzed the features of immune response of paired peripheral blood mononuclear cell (PBMC) samples from the same patients during acute and regulatory stages. Consistent with previous reports, both myeloid and T cells turned less inflammatory and less activated at recovery phase. Additionally, the communication patterns of myeloid-T cell and T-B cell are obviously changed. The crosstalk analysis reveals that typical inflammatory cytokines and several chemokines are tightly correlated with the recovery of COVID-19. Intriguingly, the signal transduction of metabolic factor insulin-like growth factor 1 (IGF1) is altered at recovery phase. Furthermore, we confirmed that the serum levels of IGF1 and several inflammatory cytokines are apparently dampened after the negative conversion of SARS-CoV-2 RNA. Thus, these results reveal several potential detection and therapeutic targets that might be used for COVID-19 recovery.

The omega-3 index is inversely associated with the neutrophil-lymphocyte ratio in adults'

The neutrophil-lymphocyte ratio (NLR) is a biomarker of systemic inflammation and measures innate-adaptive immune system balance. The omega-3-index (O3I) measures the amount of EPA+DHA in blood. Both a low O3I and an elevated NLR are associated with increased risk for chronic disease and mortality, including cardiovascular diseases and cancer. Hypothesizing that low O3I may partly contribute to systemic chronic inflammation, we asked if a relationship existed between O3I and NLR in healthy adults (≥18 y, n = 28,871, 51% female) without inflammation [C-reactive protein (CRP) <3 mg/mL)] who underwent a routine clinical assessment. NLR was inversely associated with O3I before (p < 0.0001) and after adjusting for age, sex, BMI, and CRP (p < 0.0001). Pearson correlations of other variables with NLR were r = 0.06 (CRP), r = 0.14 (age), and r = 0.01(BMI). In this healthy population, an O3I < 6.6% was associated with increasing NLR whereas NLR remained relatively constant (low) when O3I > 6.6%, suggestive of a quiescent, balanced immune system.

Neutrophil-to-lymphocyte ratio as a potential biomarker in predicting influenza susceptibility

BACKGROUND

Human population exposed to influenza viruses exhibited wide variation in susceptibility. The ratio of neutrophils to lymphocytes (NLR) has been examined to be a marker of systemic inflammation. We sought to investigate the relationship between influenza susceptibility and the NLR taken before influenza virus infection.

METHODS

We investigated blood samples from five independent influenza challenge cohorts prior to influenza inoculation at the cellular level by using digital cytometry. We used multi-cohort gene expression analysis to compare the NLR between the symptomatic infected (SI) and asymptomatic uninfected (AU) subjects. We then used a network analysis approach to identify host factors associated with NLR and influenza susceptibility.

RESULTS

The baseline NLR was significantly higher in the SI group in both discovery and validation cohorts. The NLR achieved an AUC of 0.724 on the H3N2 data, and 0.736 on the H1N1 data in predicting influenza susceptibility. We identified four key modules that were not only significantly correlated with the baseline NLR, but also differentially expressed between the SI and AU groups. Genes within these four modules were enriched in pathways involved in B cell-mediated immune responses, cellular metabolism, cell cycle, and signal transduction, respectively.

CONCLUSIONS

This study identified the NLR as a potential biomarker for predicting disease susceptibility to symptomatic influenza. An elevated NLR was detected in susceptible hosts, who may have defects in B cell-mediated immunity or impaired function in cellular metabolism, cell cycle or signal transduction. Our work can serve as a comparative model to provide insights into the COVID-19 susceptibility.

The journey of SARS-CoV-2 in human hosts: a review of immune responses, immunosuppression, and their consequences

Coronavirus disease 2019 (COVID-19) is a highly infectious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Laboratory findings from a significant number of patients with COVID-19 indicate the occurrence of leukocytopenia, specifically lymphocytopenia. Moreover, infected patients can experience contrasting outcomes depending on lymphocytopenia status. Patients with resolved lymphocytopenia are more likely to recover, whereas critically ill patients with signs of unresolved lymphocytopenia develop severe complications, sometimes culminating in death. Why immunodepression manifests in patients with COVID-19 remains unclear. Therefore, the evaluation of clinical symptoms and laboratory findings from infected patients is critical for understanding the disease course and its consequences. In this review, we take a logical approach to unravel the reasons for immunodepression in patients with COVID-19. Following the footprints of the virus within host tissues, from entry to exit, we extrapolate the mechanisms underlying the phenomenon of immunodepression.

Role of Senescence and Aging in SARS-CoV-2 Infection and COVID-19 Disease

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global pandemic associated with substantial morbidity and mortality worldwide, with particular risk for severe disease and mortality in the elderly population. SARS-CoV-2 infection is driven by a pathological hyperinflammatory response which results in a dysregulated immune response. Current advancements in aging research indicates that aging pathways have fundamental roles in dictating healthspan in addition to lifespan. Our review discusses the aging immune system and highlights that senescence and aging together, play a central role in COVID-19 pathogenesis. In our review, we primarily focus on the immune system response to SARS-CoV-2 infection, the interconnection between severe COVID-19, immunosenescence, aging, vaccination, and the emerging problem of Long-COVID. We hope to highlight the importance of identifying specific senescent endotypes (or "sendotypes"), which can used as determinants of COVID-19 severity and mortality. Indeed, identified sendotypes could be therapeutically exploited for therapeutic intervention. We highlight that senolytics, which eliminate senescent cells, can target aging-associated pathways and therefore are proving attractive as potential therapeutic options to alleviate symptoms, prevent severe infection, and reduce mortality burden in COVID-19 and thus ultimately enhance healthspan.

Association and predictive value of biomarkers with severe outcomes in hospitalized patients with SARS-CoV-2 infection

This study analyzed the levels at admission of biomarkers for their association with and ability to predict risk of severe outcomes, including admission to the ICU, need for invasive mechanical ventilation (IMV), need for vasopressor use (VU), and in-hospital mortality (IHM) in 700 patients hospitalized with COVID-19. Biomarker data split by outcomes was compared using Mann-Whitney U tests; frequencies of biomarker values were compared using Chi-square tests and multivariable logistic regression analysis was performed to look at the impact of biomarkers by outcome. Patients that suffered IHM were more likely to have reduced platelet numbers and high blood urea nitrogen (BUN) levels among patients admitted to the ICU. Risk factors for mortality were related to hyper-coagulability (low platelet count and increased D-dimer) and decreased respiratory (PaO₂/FiO₂ ratio) and kidney function (BUN). Association with risks of other severe outcomes were as follows: ICU with hyper-inflammation (IL-6) and decreased respiratory function; IMV with low platelet count, abnormal neutrophil–lymphocyte ratio with reduced respiratory function, VU with inflammatory markers (IL-6), and low platelet count with respiratory function. Our studies confirmed the association of biomarkers of hematological, inflammatory, coagulation, pulmonary and kidney functions with disease severity. Whether these biomarkers have any mechanistic or causal role in the disease progress requires further investigation.

Prognostic value of neutrophil-to-lymphocyte ratio in COVID-19 patients: A systematic review and meta-analysis

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) is an accessible and widely used biomarker. NLR may be used as an early marker of poor prognosis in patients with COVID-19.

OBJECTIVE

To evaluate the prognostic value of the NLR in patients diagnosed with COVID-19.

METHODS

We conducted a systematic review and meta-analysis. Observational studies that reported the association between baseline NLR values (ie, at hospital admission) and severity or all-cause mortality in COVID-19 patients were included. The quality of the studies was assessed using the Newcastle-Ottawa Scale (NOS). Random effects models and inverse variance method were used for meta-analyses. The effects were expressed as odds ratios (ORs) and their 95% confidence intervals (CIs). Small study effects were assessed with the Egger's test.

RESULTS

We analysed 61 studies (n = 15 522 patients), 58 cohorts, and 3 case-control studies. An increase of one unit of NLR was associated with higher odds of severity (OR 6.22; 95%CI 4.93 to 7.84; P < .001) and higher odds of all-cause mortality (OR 12.6; 95%CI 6.88 to 23.06; P < .001). In our sensitivity analysis, we found that 41 studies with low risk of bias and moderate heterogeneity (I2  = 53% and 58%) maintained strong association between NLR values and both outcomes (severity: OR 5.36; 95% CI 4.45 to 6.45; P < .001; mortality: OR 10.42 95% CI 7.73 to 14.06; P = .005).

CONCLUSIONS

Higher values of NLR were associated with severity and all-cause mortality in hospitalised COVID-19 patients.

Marginating transitional B cells modulate neutrophils in the lung during inflammation and pneumonia

Pulmonary innate immunity is required for host defense; however, excessive neutrophil inflammation can cause life-threatening acute lung injury. B lymphocytes can be regulatory, yet little is known about peripheral transitional IgM+ B cells in terms of regulatory properties. Using single-cell RNA sequencing, we discovered eight IgM+ B cell subsets with unique gene regulatory networks in the lung circulation dominated by transitional type 1 B and type 2 B (T2B) cells. Lung intravital confocal microscopy revealed that T2B cells marginate in the pulmonary capillaries via CD49e and require CXCL13 and CXCR5. During lung inflammation, marginated T2B cells dampened excessive neutrophil vascular inflammation via the specialized proresolving molecule lipoxin A4 (LXA4). Exogenous CXCL13 dampened excessive neutrophilic inflammation by increasing marginated B cells, and LXA4 recapitulated neutrophil regulation in B cell-deficient mice during inflammation and fungal pneumonia. Thus, the lung microvasculature is enriched in multiple IgM+ B cell subsets with marginating capillary T2B cells that dampen neutrophil responses.

Differences in the neutrophil/lymphocyte ratio and the platelet/lymphocyte ratio in pregnant women with and without COVID-19

OBJECTIVE

To determine the differences in the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR) in pregnant women with and without COVID-19.

METHODS

Observational, cross-sectional, retrospective, comparative, open, controlled study done from January to April 2021 at the UMAE Hospital de Gineco Obstetricia "Luis Castelazo Ayala" Instituto Mexicano del Seguro Social. Mexico City, Mexico: Patients were divided into those with a negative test for COVID-19 and those with a positive test, with the latter then being divided according to disease severity into mild, moderate, and severe groups. In all the NLR and PLR were calculated. Symptoms, vital signs, and oxygen saturation were documented.

STATISTICAL ANALYSIS

Central tendency and dispersion measures, Kruskal-Wallis test, Mann-Whitney U test, and chi-squared test were used. Sensitivity, specificity, positive predictive value, negative predictive value, and odds ratio (OR) were calculated.

RESULTS

Seventy-seven patients were included, 24 without COVID-19 and 53 with COVID-19. There were 33, 10, and 10 patients in the mild, moderate, and severe disease groups, respectively. There was no difference in NLR between the groups and the PLR was significantly higher in the severe disease group. With a 5.1 NLR cutoff point, between normal and those with severe disease, the sensitivity was 70% and specificity 63%, whilst with a 221 PLR cutoff point, the sensitivity was 90% and the specificity 83% (OR 45, 95% CI 4.40-461.7).

CONCLUSION

PLR more than NLR was useful to detect pregnant patients with COVID-19 with severe disease.

Comparison of hemoglobin level and neutrophil to lymphocyte ratio as prognostic markers in patients with COVID-19

Background

Anemia can negatively affect the outcome of many diseases, including infections and inflammatory conditions.

Aim

To compare the prognostic value of hemoglobin level and the neutrophil/lymphocyte ratio (NLR) for prediction of coronavirus disease 2019 (COVID-19) severity.

Methods

In this retrospective cohort study, clinical data from patients with laboratory-confirmed COVID-19 were collected from hospital records from 10 April 2020 to 30 July 2020.

Results

The proportions of patients with mild, moderate, and severe COVID-19 differed significantly in association with hemoglobin levels, neutrophil counts, lymphocyte counts, NLR, and total leukocyte counts. Patients with severe COVID-19 had significantly lower hemoglobin levels than those with moderate or mild COVID-19. There were statistically significant negative associations between hemoglobin and D-dimer, age, and creatinine. The optimal hemoglobin cut-off value for prediction of disease severity was 11.6 g/dL. Using this cut-off value, hemoglobin had higher negative predictive value and sensitivity than NLR (92.4% and 51.3%, respectively). The specificity of hemoglobin as a prognostic marker was 79.3%.

Conclusion

Both NLR and hemoglobin level are of prognostic value for predicting severity of COVID-19. However, hemoglobin level displayed higher sensitivity than NLR. Hemoglobin level should be assessed upon admission in all patients and closely monitored throughout the disease course.

Distinct clinical and immunological profiles of patients with evidence of SARS-CoV-2 infection in sub-Saharan Africa

Although the COVID-19 pandemic has left no country untouched there has been limited research to understand clinical and immunological responses in African populations. Here we characterise patients hospitalised with suspected (PCR-negative/IgG-positive) or confirmed (PCR-positive) COVID-19, and healthy community controls (PCR-negative/IgG-negative). PCR-positive COVID-19 participants were more likely to receive dexamethasone and a beta-lactam antibiotic, and survive to hospital discharge than PCR-negative/IgG-positive and PCR-negative/IgG-negative participants. PCR-negative/IgG-positive participants exhibited a nasal and systemic cytokine signature analogous to PCR-positive COVID-19 participants, predominated by chemokines and neutrophils and distinct from PCR-negative/IgG-negative participants. PCR-negative/IgG-positive participants had increased propensity for Staphylococcus aureus and Streptococcus pneumoniae colonisation. PCR-negative/IgG-positive individuals with high COVID-19 clinical suspicion had inflammatory profiles analogous to PCR-confirmed disease and potentially represent a target population for COVID-19 treatment strategies.

A Shift Towards an Immature Myeloid Profile in Peripheral Blood of Critically Ill COVID-19 Patients

BACKGROUND

SARS-CoV-2, the etiological agent causing COVID-19, has infected more than 27 million people with over 894000 deaths worldwide since its emergence in December 2019. Factors for severe diseases, such as diabetes, hypertension, and obesity have been identified however, the precise pathogenesis is poorly understood. To understand its pathophysiology and to develop effective therapeutic strategies, it is essential to define the prevailing immune cellular subsets.

METHODS

We performed whole circulating immune cells scRNAseq from five critically ill COVID-19 patients, trajectory and gene ontology analysis.

RESULTS

Immature myeloid populations, such as promyelocytes-myelocytes, metamyelocytes, band neutrophils, monocytoid precursors, and activated monocytes predominated. The trajectory with pseudotime analysis supported the finding of immature cell states. While the gene ontology showed myeloid cell activation in immune response, DNA and RNA processing, defense response to the virus, and response to type 1 interferon. Lymphoid lineage was scarce. Expression of genes such as C/EBPβ, IRF1and FOSL2 potentially suggests the induction of trained immunity.

CONCLUSIONS

Our results uncover transcriptomic profiles related to immature myeloid lineages and suggest the potential induction of trained immunity.

Ratios between circulating myeloid cells and lymphocytes are associated with mortality in severe COVID-19 patients

Recent studies indicate that host immune responses are dysregulated with either myeloid cell compartment or lymphocyte composition being disturbed in COVID-19. This study aimed to assess the impact of SARS-CoV-2 viral infection on the composition of circulating immune cells in severe COVID-19 patients. In this retrospective single-center cohort, 71 out of 87 COVID-19 patients admitted to the intense care unit for oxygen treatment were included in this study. Demographics, clinical features, comorbidities, and laboratory findings were collected on admission. Out of the 71 patients, 5 died from COVID-19. Compared with survived patients, deceased patients showed higher blood cell counts of neutrophils and monocytes but lower cell counts of lymphocytes. Intriguingly, the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and basophil-to-lymphocyte ratio (BLR) were markedly higher in deceased patients compared to survived patients. Furthermore, the lymphocyte counts were negatively correlated with D-dimer levels, while the ratios between myeloid cells and lymphocyte (NLR, MLR, and BLR) were positively correlated with D-dimer levels. Our findings revealed that the ratios between myeloid cells and lymphocytes were highly correlated with coagulation status and patient mortality in severe COVID-19.

In depth analysis of patients with severe SARS-CoV-2 in sub-Saharan Africa demonstrates distinct clinical and immunological profiles

Although the COVID-19 pandemic has left no country untouched there has been limited research to understand clinical and immunological responses in African populations. Here we comprehensively characterise patients hospitalised with suspected or confirmed COVID-19, and healthy community controls. PCR-confirmed COVID-19 participants were more likely to receive dexamethasone and a beta-lactam antibiotic, and survive to hospital discharge than PCR-/IgG+ and PCR-/IgG-participants. PCR-/IgG+ participants exhibited a nasal and systemic cytokine signature analogous to PCR-confirmed COVID-19 participants, but increased propensity for Staphylococcus aureus and Streptococcus pneumoniae colonisation. We did not find evidence that HIV co-infection in COVID-19 participants was associated with mortality or altered cytokine responses. The nasal immune signature in PCR-/IgG+ and PCR-confirmed COVID-19 participants was distinct and predominated by chemokines and neutrophils. In addition, PCR-/IgG+ individuals with high COVID-19 clinical suspicion had inflammatory profiles analogous to PCR-confirmed disease and potentially represent a target population for COVID-19 treatment strategies.

SARS-CoV-2-Diagnostik – was ist wirklich sinnvoll?

Den Goldstandard zur Diagnose einer Infektion mit SARS-CoV-2 stellt aktuell (Stand November 2020) die PCR-Untersuchung dar. Diese ist jedoch vor allem zeitintensiv. In Zukunft könnten sog. Antigentests schnell und patientennah als Point-of-Care-Methode durchgeführt werden, um die Diagnosestellung einer SARS-CoV-2 Infektion zu erleichtern. Veränderungen serologischer Biomarker (wie D-Dimere, Troponin T, CRP) können helfen, Patienten mit einem Risiko für einen schweren COVID-19-Verlauf zu identifizieren. Ein routinemäßiges Screening-CT-Thorax zur Identifizierung einer COVID-19-Pneumonie wird derzeit von den meisten radiologischen Gesellschaften nicht empfohlen. Dennoch nimmt die Zahl der durchgeführten CT-Untersuchungen kontinuierlich zu, und die radiologische Diagnostik nimmt bei an COVID-19 erkrankten Patienten mit pulmonalen Symptomen einen immer wichtigeren Stellenwert in der klinischen Erfassung der Schwere der Lungenbeteiligung ein.

Maturation of T and B Lymphocytes in the Assessment of the Immune Status in COVID-19 Patients

Cell response to novel coronavirus disease 19 (COVID-19) is currently a widely researched topic. The assessment of leukocytes population and the maturation of both B and T lymphocytes may be important in characterizing the immunological profile of COVID-19 patients. The aim of the present study was to evaluate maturation of B and T cells in COVID-19 patients with interstitial lesions on chest X-ray (COVID-19 X-ray (+)), without changes on X-ray (COVID-19 X-ray (-)) and in healthy control. The study group consisted of 23 patients divided on two groups: COVID-19 X-ray (+) n = 14 and COVID-19 X-ray (-) n = 9 and control n = 20. The flow cytometry method was performed. We observed a significantly higher percentage of plasmablasts and lower CD4+ lymphocytes in COVID-19 X-ray (+) patients than in COVID-19 X-ray (-) and control. In the COVID-19 X-ray (+) patients, there was a lower proportion of effector CD4+ T cells, naïve CD8+ T cells and higher central memory CD4+ cells and effector CD8+ T cells than control. The above results showed that the assessment of selected cells of B and T lymphocytes by flow cytometry can distinguish patients with COVID-19 and differentiate patients with and without changes on chest X-ray.

Proposal of COVID-19 Clinical Risk Score for the management of suspected COVID-19 cases: a case control study

BACKGROUND

No clinical scoring system has yet been established to estimate the likelihood of coronavirus disease (COVID-19) and determine the suitability of diagnostic testing in suspected COVID-19 patients.

METHODS

This was a single-center, retrospective, observational study of patients with suspected COVID-19 and confirmed COVID-19. Patient background, clinical course, laboratory and computed tomography (CT) findings, and the presence of alternative diagnoses were evaluated. Clinical risk scores were developed based on clinical differences between patients with and without COVID-19.

RESULTS

Among 110 patients suspected of having COVID-19, 60.9% underwent polymerase chain reaction (PCR) testing based on the judgment of physicians. Two patients were found to have COVID-19. The clinical characteristics of 108 non-COVID-19 patients were compared with those of 23 confirmed COVID-19 patients. Patients with COVID-19 were more likely to have a history of high-risk exposures and an abnormal sense of taste and smell. The COVID-19 group had significantly higher rates of subnormal white blood cell counts, lower eosinophil counts, and lower procalcitonin levels than the non-COVID-19 group. When blood test results, CT findings, and the presence of alternative diagnoses were scored on an 11-point scale (i.e., "COVID-19 Clinical Risk Score"), the COVID-19 group scored significantly higher than the non-COVID-19 group, more than four points in the COVID-19 group. All non-COVID patients who did not undergo PCR had a score of 4 or less.

CONCLUSIONS

The COVID-19 Clinical Risk Score may enable the risk classification of patients suspected of having COVID-19 and can help in decision-making in clinical practice, including appropriateness of diagnostic testing. Further studies and prospective validation with an increased sample size are required.