The Impact of Neutrophil-Lymphocyte Count Ratio in COVID-19: A Systematic Review and Meta-Analysis

Hematological ratios in patients with acute decompensation and acute-on-chronic liver failure: prognostic factors

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is the most severe form of acutely decompensated cirrhosis and is characterized by the presence of intense systemic inflammation. Leucocyte quantification can serve as an indirect indicator of systemic inflammation. In our study, we investigated the predictive value of hematological ratios (neutrophils to lymphocytes, monocyte to lymphocytes, platelets to lymphocytes, lymphocytes to C-reactive protein, and neutrophils to lymphocytes and platelets) in acute decompensation (AD) and ACLF patients and their relation to disease severity and early mortality.

PATIENTS AND METHODS

We included 60 patients with ACLF and AD, and 30 cirrhotic controls. Clinical data were collected, and survival was followed for 1 and 6 months. Blood samples were analyzed at admission for differential leucocytes and assessed for liver and renal function tests. The leukocyte ratios were calculated and compared, and their correlation with liver function indicators and prognosis was assessed.

RESULTS

All ratios were significantly higher in AD and ACLF patients compared to control (except for lymphocyte to C-reactive protein ratio which was significantly lower), and were positively correlated with Child-Pugh score, model for end-stage liver disease (MELD)-Na, and ACLF severity scores. Multivariate regression revealed that neutrophil to lymphocyte ratio, monocyte to lymphocyte ratio, and MELD-Na were independent prognostic factors of 1-month and 6-month mortality. A unique prognostic nomogram incorporating MELD-Na, neutrophil to lymphocyte ratio, and monocyte to lymphocyte ratio could be proposed for predicting prognosis in AD and ACLF patients.

CONCLUSIONS

Cheap, easy, and noninvasive hematological ratios are introduced as a tool for early identification and risk stratification of AD and ACLF patients.

Inflammatory and Autoimmune Aspects of Multisystem Inflammatory Syndrome in Children (MIS-C): A Prospective Cohort Study

Multisystem Inflammatory Syndrome in Children (MIS-C) is a potentially life-threatening complication of COVID-19. The pathophysiological mechanisms leading to severe disease are poorly understood. This study leveraged clinical samples from a well-characterized cohort of children hospitalized with COVID-19 or MIS-C to compare immune-mediated biomarkers. Our objective was to identify selected immune molecules that could explain, in part, why certain SARS-CoV-2-infected children developed MIS-C. We hypothesized that type-2 helper T cell-mediated inflammation can elicit autoantibodies, which may account for some of the differences observed between the moderate-severe COVID-19 (COVID+) and MIS-C cohort. We enumerated blood leukocytes and measured levels of selected serum cytokines, chemokines, antibodies to COVID-19 antigens, and autoantibodies in children presenting to an academic medical center in Connecticut, United States. The neutrophil/lymphocyte and eosinophil/lymphocyte ratios were significantly higher in those in the MIS-C versus COVID+ cohort. IgM and IgA, but not IgG antibodies to SARS-CoV-2 receptor binding domain were significantly higher in the MIS-C cohort than the COVID+ cohort. The serum levels of certain type-2 cytokines (interleukin (IL)-4, IL-5, IL-6, IL-8, IL-10, IL-13, and IL-33) were significantly higher in children with MIS-C compared to the COVID+ and SARS-CoV-2-negative cohorts. IgG autoantibodies to brain antigens and pentraxin were higher in children with MIS-C compared to SARS-CoV-19-negative controls, and children with MIS-C had higher levels of IgG anti-contactin-associated protein-like 2 (caspr2) compared to the COVID+ and SARS-CoV-19-negative controls. We speculate that autoimmune responses in certain COVID-19 patients may induce pathophysiological changes that lead to MIS-C. The triggers of autoimmunity and factors accounting for type-2 inflammation require further investigation.

The Impact of COVID-19 on the Tuberculosis Features in a Romanian Pneumology Hospital

Introduction

The COVID-19 pandemic and tuberculosis have epidemiological similarities, being transmitted airborne, favored by direct contact, crowded environments, and vulnerable biological status.

Methods

We performed a retrospective study of 45 cases of pulmonary tuberculosis associated with COVID-19 (TB+COV+) compared to 45 cases with tuberculous monoinfection (TB+COV-), hospitalized during 2021-2022.

Results

The demographic characteristics were similar in the two groups, predominating men, a median age of 51 years, living in rural areas, medium level of education and smoking. Common symptoms of the two groups were cough, weight loss, profuse sweating, loss of appetite and hemoptysis, while fever, headache, myo-arthralgias, and digestive symptoms characterized the TB+COV+ forms. The scores of radiological lesions in the TB+COV+ compared to TB+COV- group were significantly higher and persistent, revealing more frequent bilateral extensive lung lesions. There were no significant differences in the biological parameters between the two groups. Mortality was 2.2%, regardless of the association of COVID-19. The frequency of infections with Clostridioides difficile was higher in TB+COV+ cases.

Conclusion

The co-infection of COVID-19 had a mild impact on the clinical and biological expression of tuberculosis diagnosed in a pandemic context.

Predictive ability of complete blood count, mean platelet ratio, mean platelet volume, and neutrophil/lymphocyte ratio for severe pneumonia among RT-PCR or radiologically proven COVID-19 patients

Background

Immuno-inflammatory markers related to white blood cells, and platelets are shown to be associated with COVID-19 infection, and considered to be independent markers for clinical outcomes and mortality. The present study aimed to study the predictive value of these hematologic parameters in progression of COVID-19 to severe pneumonia.

Methods

This was an analytical cross-sectional study conducted among RT-PCR or radiologically proven COVID-19 patients in a tertiary care hospital in Rajasthan. Semi-structured questionnaire was used to collect the epidemiological information of the patients with COVID-19. Complete blood count and other laboratory parameters were also studied among the patients.

Results

Mean age of participants in the study was 52 years, with about 70% being males. Cough and breathlessness were the most common symptoms among the patients. It was found that the parameters related to white blood cells were significantly different between patients with COVID-19 infection and severe pneumonia (except absolute monocyte count). NLR was significantly higher among those with severe pneumonia. In the univariate analysis, age (OR - 1.02), NLR (OR - 1.16), and albumin (OR - 0.45) were found to be significant predictors of progression to severe pneumonia. In the final model, adjusted for confounders, only NLR and albumin levels significantly predicted progression to severe pneumonia among COVID-19 patients.

Conclusion

The study consolidates the predictive ability of NLR for severe pneumonia. It is an important finding, as health facilities with limited access to laboratory investigations can rely on simple markers in routine practice to predict the progression of COVID-19 infection to severe pneumonia.

Prognostic Significance of NLR and PLR in COVID-19: A Multi-Cohort Validation Study

INTRODUCTION

Recent studies have highlighted the prognostic value of easily accessible inflammatory markers, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) for predicting severe outcomes in patients affected by Coronavirus disease 2019 (COVID-19). Our study validates NLR and PLR cut-off values from a prior cohort at IRCCS Policlinico San Matteo (OSM) of Pavia, Italy, across two new cohorts from different hospitals. This aims to enhance the generalizability of these prognostic indicators.

METHODS

In this retrospective cohort study, conducted at Milan's Ospedale Luigi Sacco (OLS) and IRCCS Ospedale Maggiore Policlinico (OMP) hospitals, we assess the predictive capacity of NLR and PLR for three main outcomes-non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) usage, invasive ventilation (IV), and death-in patients with COVID-19 at admission. For each outcome, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were computed separately for male and female cohorts. Distinct NLR and PLR cut-off values were used for men (7.00, 7.29, 7.00 for NLR; 239.22, 248.00, 250.39 for PLR) and women (6.36, 7.00, 6.28 for NLR; 233.00, 246.45, 241.54 for PLR), retrieved from the first cohort at OSM.

RESULTS

A total of 3599 patients were included in our study, 1842 from OLS and 1757 from OMP. OLS and OMP sensitivity values for both NLR and PLR (NLR: 24-67%, PLR: 40-64%) were inferior to specificity values (NLR: 64-76%, PLR: 55-72%). Additionally, PPVs generally remained lower (< 63%), while NPVs consistently surpassed 68% for PLR and 72% for NLR. Finally, both PLR and NLR exhibited consistently higher NPVs for more severe outcomes (> 82%) compared to NPVs for CPAP/NIV.

CONCLUSIONS

Consistent findings across diverse patient populations validate the reliability and applicability of NLR and PLR cut-off values. High NPVs emphasize their role in identifying individuals less likely to experience severe outcomes. These markers not only aid in risk stratification but also guide resource allocation in emergencies or limited-resource situations.

Association of soluble PD-L1 and NLR combination with 1-Year mortality in patients with COVID-19

PURPOSE

Understanding the relationship between patient immune characteristics, disease severity, and mortality represents a critical step in the fight against COVID-19. Elevated levels of programmed death ligand-1 (PD-L1) and Neutrophil-lymphocyte ratio (NLR) are linked to increased severity of acute COVID-19 in patients. This study aimed to investigate the association of the combination of sPD-L1 and NLR with 1-year Mortality in patients with COVID-19.

METHODS

A prospective study was conducted involving patients with COVID-19 in Karaganda, Kazakhstan. The level of sPD-L1 in the blood serum was evaluated by ELISA. The effect of biomarkers on the development of mortality was analyzed with multivariate regression.

RESULTS

The risk of mortality within one year HR was 2.46 if the plasma sPD-L1 value of more than 277.13 pg/ml, and for NLR more than 2.46 HR was 2.87. The model of combining sPD-L1 and NLR resulted in an improvement in the predictive accuracy of the Hazard Ratio 7.6 (95 % CI: 3.02-19.11).

CONCLUSION

The combination of two immune-mediated markers (sPD-L1 and NLR), which reflect the systemic inflammatory balance of activation and exhaustion, can complement each other and improve the assessment of the risk of death in patients with COVID-19.

Role of biomarkers in prognostication of moderate and severe COVID-19 cases

Background

COVID-19 pandemic demanded upgrading of laboratory medicine to limit morbidity, disability and mortality from moderate and severe SARS-COV-2 infections.

Objective

To assess among moderate and severe COVID-19 patients, C-reactive protein (CRP), procalcitonin (PCT), ferritin, D-dimer, interleukin 6 (IL-6), lactate dehydrogenase (LDH), total and differential leucocyte count (TLC and DLC), neutrophil-to-lymphocyte ratio (NLR), absolute platelet count (APC), prothrombin time (PT), activated partial thromboplastin time (APTT) and international normalized ratio (INR) to find their interdependence and role in prognosis.

Methods

This open label analytical cross-sectional noninterventional study evaluated array of independent biochemical, haematological and coagulopathy markers, viz. CRP, PCT, ferritin, D-dimer, IL-6, LDH, TLC, DLC, NLR, absolute platelet count, PT, APTT and INR on consecutive 100 patients with diagnosis of moderate and severe COVID-19 from July to August 2021.

Results

In our study, on consecutive designated 100 cases (55 cases moderate and 45 cases severe), more severity were reported as the age progressed; gender difference was not noted. Among independent markers, CRP, PCT, ferritin, D-dimer, IL-6 and LDH had statistically significant relation in comparison with severity of the disease as Chi-square calculated value (P < 0.05). TLC, DLC and APC showed no significant relation in comparison with severity of the disease; NLR had highly significant relation. PT showed significant relation in comparison with severity, though APTT and INR did not show significant relation.

Conclusion

Our research group felt that CRP, PCT, ferritin, D-dimer, IL-6, LDH and NLR should be in included in clinical practice guidelines to prognosticate COVID-19 cases. Furthermore, translational researches are needed at all levels of healthcare to improve validity for practices of primary care physicians.

The influence of SARS-CoV-2 on the immune system elements and on the placental structure. Clinical, histological and immunohistochemical study

BACKGROUND

The effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy remain relatively unknown.

AIM

We present this original paper where we analyzed 60 parturients, at term, 30 without associated infection (C-) and 30 with associated infection (C+), present at birth.

METHODS

We analyzed the blood count and placental microscopic structure through classical and immunohistochemical staining and observed the placental areas affected by the presence of SARS-CoV-2.

RESULTS

SARS-CoV-2 infection was accompanied by a decrease in the number of lymphocytes, the number of platelets and the presence of placental structural changes, identifying extensive areas of amyloid deposits, placental infarcts, vascular thrombosis, syncytial knots, with a decrease in placental vascular density and the presence of infection in the cells located at decidual level, at syncytiotrophoblast level and at the level of the cells of the chorionic plate, still without overcoming this barrier and without causing any fetal infection in the analyzed cases.

CONCLUSIONS

This study shows that the invasion of SARS-CoV-2 in the placenta can produce significant structural changes, with a decrease in placental vascular density that can have significant implications on proper fetal perfusion. Also, the presence of immunoreactivity at the level of decidua, the placental villi, as well as the chorionic plate proves that the virus can overcome the maternal-fetal barrier. However, in the analyzed cases there were no fetal infections at birth, which may show that local placental factors can be a protective filter for the fetus.

Temporal evolution of laboratory characteristics in patients critically ill with COVID‑19 admitted to the intensive care unit (Review)

In the context of coronavirus disease 2019 (COVID-19), laboratory medicine has played a crucial role in both diagnosis and severity assessment. Although the importance of baseline laboratory findings has been extensively reported, data regarding their evolution over the clinical course are limited. The aim of the present narrative review was to provide the dynamic changes of the routine laboratory variables reported in patients with severe COVID-19 over the course of their critical illness. A search was made of the literature for articles providing data on the time-course of routine laboratory tests in patients with severe COVID-19 during their stay in the intensive care unit (ICU). White blood cell, neutrophil and lymphocyte counts, neutrophil to lymphocyte ratio, platelet counts, as well as D-dimer, fibrinogen, C-reactive protein, lactate dehydrogenase and serum albumin levels were selected as disease characteristics and routine laboratory parameters. A total of 25 research articles reporting dynamic trends in the aforementioned laboratory parameters over the clinical course of severe COVID-19 were identified. During the follow-up period provided by each study, the majority of the laboratory values remained persistently abnormal in both survivors and non-survivors. Furthermore, in the majority of studies, the temporal trends of laboratory values distinctly differentiated patients between survivors and non-survivors. In conclusion, there are distinct temporal trends in selected routine laboratory parameters between survivors and non-survivors with severe COVID-19 admitted to the ICU, indicating their importance in the prognosis of clinical outcome.

The Impact of Viral and Bacterial Co-Infections and Home Antibiotic Treatment in SARS-CoV-2 Hospitalized Patients at the Policlinico Tor Vergata Hospital, Rome, Italy

Co-infections during COVID-19 may worsen patients' outcomes. This study reports the results of a screening assessing the presence of co-infections among patients hospitalized for SARS-CoV-2 infection in the Infectious Diseases-Ward of the Policlinico Tor Vergata Hospital, Rome, Italy, from 1 January to 31 December 2021. Data on hepatitis B and C virus, urinary antigens for legionella pneumophila and streptococcus pneumoniae, pharyngeal swab for respiratory viruses, QuantiFERON®-TB Gold Plus assay (QFT-P), blood cultures and pre-hospitalization antibiotic prescription were recorded. A total of 482 patients were included, 61% males, median age of 65 years (IQR 52-77), median Charlson comorbidity index of 4 (IQR 2-5). The mortality rate was 12.4%; 366 patients needed oxygen supply. In total, 151 patients (31.3%) received home antibiotics without any association with the outcome. No significant association between mortality and the positivity of viral hepatitis markers was found. Out of 442 patients, 125 had an indeterminate QFT-P, associated with increased mortality. SARS-CoV-2 was the only respiratory virus detected among 389 pharyngeal swabs; 15/428 patients were positive for S. pneumoniae; none for L. pneumophila. In total, 237 blood cultures were drawn within 48 h from hospital admission: 28 were positive and associated with increased mortality. In our cohort, bacterial and viral co-infections in COVID-19 hospitalized patients were rare and not associated with higher mortality.

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.

Differential Characteristics of Patients for Hospitalized Severe COVID-19 Infected by the Omicron Variants and Wild Type of SARS-CoV-2 in China

Background

As multiple mutations of SARS-Cov-2 exist, there are now many viral variants with regional differences in distribution. The clinical characteristics of patients hospitalized with the virus also vary significantly, with those of the Omicron variants being strikingly different from those of the earliest wild-type variant. However, comprehensive data on this subject is lacking. It is therefore crucial to explore these differences to develop better clinical strategies for the management of COVID-19.

Methods

A total of 554 confirmed COVID-19 cases in China were clinically classified as mild, moderate, severe, and critical according to their diagnoses and treatment plans. We compared the demographics and clinical characteristics of patients infected with the Omicron vs wild-type strains, between severe and non-severe cases. Bacterial co-infections with SARS-CoV-2 and correlation between inflammatory factors and T cells were analyzed.

Results

Compared to the wild-type cases, the severe Omicron cases were older (median age 48.36 vs 73.24), and had more upper-respiratory symptoms and comorbidities. Decreased leukocyte counts were less pronounced, although more instances of significantly decreased CD4+ and CD8+ T-cell counts, elevated infection-related biomarkers (eg procalcitonin and C-reactive protein), and abnormal coagulation factors (including increased D-dimer and fibrinogen levels) were detected in the severe Omicron cases. The mean length of hospital stay was significantly shorter in the severe Omicron cases. CD4+ and CD8+ T cell numbers were negatively correlated with neutrophil-to-lymphocyte ratios, as well as serum interleukin-6, procalcitonin, and C-reactive protein levels.

Conclusion

There were significant clinical differences between patients hospitalized with severe cases of Omicron- variant COVID-19 vs wild-type. The Omicron cases tended to be older and had more upper respiratory tract symptoms, comorbidities and bacterial co-infections. Elevated levels of inflammatory cytokines with T-cell depletion correlated with poor disease progression and prognosis. We hope these data provide a theoretical basis for future integrated prevention and control plans for COVID-19.

Changes and Rate of Change in Neutrophil-Lymphocyte Ratio (∆NLR) as an Early Prognostic Marker for the Severity of Outcomes in Patients With COVID-19 and Its Applicability in Other Viral and Bacterial Diseases

INTRODUCTION

COVID-19 is a global pandemic that has spread rapidly and resulted in numerous deaths worldwide. Many inflammatory markers such as neutrophil-lymphocyte ratio (NLR), D-dimer, serum ferritin, C-reactive protein (CRP), and interleukin-6 (IL-6) were used for the diagnosis and prognosis of COVID-19.

METHODS

We have proposed using Delta NLR (0-48 hours) (∆NLR) as an early diagnostic marker for COVID-19 and other inflammatory disorders. We have created a prediction model based on six variables: overall severity, death, shifting to the ICU, length of stay, oxygen requirement, and ventilator support. Prediction models help us prepare for future pandemics through early diagnosis and management.

RESULTS

A total of 1,865 patient records were retrieved from the database. The final sample available for analysis was 461. Change in NLR or ∆NLR was significant for all the models (except for length of stay) created by logistic regression.

CONCLUSION

An independent predictor of the poor prognosis of COVID-19 is the severity of the disease in the initial one or two days. ∆NLR is a unique marker, and its scope of use in other disorders' prognoses must be further researched. The prediction models also help us in decision-making strategies and also prepare us for future pandemics.

Longitudinal whole blood transcriptomic analysis characterizes neutrophil activation and interferon signaling in moderate and severe COVID-19

A maladaptive inflammatory response has been implicated in the pathogenesis of severe COVID-19. This study aimed to characterize the temporal dynamics of this response and investigate whether severe disease is associated with distinct gene expression patterns. We performed microarray analysis of serial whole blood RNA samples from 17 patients with severe COVID-19, 15 patients with moderate disease and 11 healthy controls. All study subjects were unvaccinated. We assessed whole blood gene expression patterns by differential gene expression analysis, gene set enrichment, two clustering methods and estimated relative leukocyte abundance using CIBERSORT. Neutrophils, platelets, cytokine signaling, and the coagulation system were activated in COVID-19, and this broad immune activation was more pronounced in severe vs. moderate disease. We observed two different trajectories of neutrophil-associated genes, indicating the emergence of a more immature neutrophil phenotype over time. Interferon-associated genes were strongly enriched in early COVID-19 before falling markedly, with modest severity-associated differences in trajectory. In conclusion, COVID-19 necessitating hospitalization is associated with a broad inflammatory response, which is more pronounced in severe disease. Our data suggest a progressively more immature circulating neutrophil phenotype over time. Interferon signaling is enriched in COVID-19 but does not seem to drive severe disease.

Clinicopathologic Analysis of COVID‐19 Associated Thrombi in the Setting of Large Vessel Occlusion: A Prospective Case–Control Study

BACKGROUND

Acute ischemic stroke secondary to large vessel occlusion is among the most serious complications associated with COVID‐19 infection resulting in worse morbidity and mortality. We sought to study the association between COVID‐19 infection and large vessel occlusion thrombus pathology to better define the etiopathogenesis of this atypical cause of stroke.

METHODS

Thrombi were collected during mechanical thrombectomy and stained using hematoxylin and eosin. Blinded analysis of pathology was prospectively performed by a board‐certified neuropathologist. Red blood cell, fibrin, and white blood cell predominance was ascertained. Concomitant peripheral blood counts and clinical and imaging data were collected and analyzed. All samples underwent performance of reverse transcription polymerase chain reaction for SARS‐CoV2.

RESULTS

Between January 2020 and February 2022, a total of 952 acute ischemic stroke admissions were seen at the University Medical Center of El Paso, TX. Of these, 195 patients (20.5%) had large vessel occlusions and underwent mechanical thrombectomy and 53 patients had thrombus collected and analyzed. Seven patients (3.6%) tested positive for SARS‐CoV2. COVID‐19 positive patients were more likely to be younger (mean 57.4 years; P =0.07), male (85.7%; P =0.03), and have red blood cell predominant thrombi (85.7%; P =0.03). There was a statistically significant association between peripheral neutrophil count and white blood cell lysis in the overall cohort ( P =0.015), who did not differ according to COVID‐19 status.

CONCLUSION

Thrombi retrieved from patients who were COVID‐19 positive and had stroke demonstrated red blood cell predominance. This finding requires further investigation using appropriate immunohistochemical techniques in a larger cohort of patients.

COVID-19 Biomarkers at the Crossroad between Patient Stratification and Targeted Therapy: The Role of Validated and Proposed Parameters

Clinical knowledge about SARS-CoV-2 infection mechanisms and COVID-19 pathophysiology have enormously increased during the pandemic. Nevertheless, because of the great heterogeneity of disease manifestations, a precise patient stratification at admission is still difficult, thus rendering a rational allocation of limited medical resources as well as a tailored therapeutic approach challenging. To date, many hematologic biomarkers have been validated to support the early triage of SARS-CoV-2-positive patients and to monitor their disease progression. Among them, some indices have proven to be not only predictive parameters, but also direct or indirect pharmacological targets, thus allowing for a more tailored approach to single-patient symptoms, especially in those with severe progressive disease. While many blood test-derived parameters quickly entered routine clinical practice, other circulating biomarkers have been proposed by several researchers who have investigated their reliability in specific patient cohorts. Despite their usefulness in specific contexts as well as their potential interest as therapeutic targets, such experimental markers have not been implemented in routine clinical practice, mainly due to their higher costs and low availability in general hospital settings. This narrative review will present an overview of the most commonly adopted biomarkers in clinical practice and of the most promising ones emerging from specific population studies. Considering that each of the validated markers reflects a specific aspect of COVID-19 evolution, embedding new highly informative markers into routine clinical testing could help not only in early patient stratification, but also in guiding a timely and tailored method of therapeutic intervention.

Evaluation of Inflammation-Based Prognostic Risk Scores in Predicting in-Hospital Mortality Risk in COVID-19 Patients: A Cross-Sectional Retrospective Study

Objective

Systemic inflammatory parameters are predictors of poor prognosis in COVID-19 patients. This study evaluated whether the prognostic nutritional index, which was also related to nutrition risk and other inflammation-based prognostic scores, was predictive of in-hospital mortality in COVID-19 patients.

Materials and Methods

This was a retrospective cross-sectional single-center study. Based on the exclusion criteria, 151 patients over 18 years old diagnosed with COVID-19 and hospitalized in the intensive care unit between March 2020 and December 2020 were eligible for this study. Multivariable logistic regression analysis was performed to evaluate the predictive value of the Glasgow Prognostic Score (GPS), Prognostic Index (PI), Prognostic Nutritional Index (PNI), and Systemic Inflammatory Index (SII).

Results

In the univariate analyses, age, diabetes mellitus (DM), chronic kidney disease, acute kidney injury, hypothyroidism, hospitalization stay, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), D-dimer, ferritin, C-reactive protein (CRP), albumin, hemoglobin level, platelet count, urea, creatinine level, PNI, GPS were significantly associated with mortality. However, in the multivariable logistic regression analysis of the inflammation-based prognostic scores, only PNI was statistically significant in predicting in-hospital mortality (OR=0.83; [95% CI=0.71-0.97]; p =0.019).

Conclusion

PNI is a more useful and powerful tool among these inflammation-based prognostic risk scores in predicting in-hospital mortality in COVID-19 patients.

Neurological Manifestations of Non-Severe COVID-19-A Multidirectional Approach

COVID-19 remains a significant clinical issue worldwide, with frequent neurological manifestations. In this study, the authors combine data obtained from the patient's medical history, physical examinations, and additional test results in the pursuit of any clinically relevant connections. Fifty-eight adult patients hospitalized in the Department of Neurology and Infectiology over a five-months period were retrospectively enrolled in this study. On admission, all patients included in this study were classified as mild or moderate COVID-19 cases, according to the World Health Organization (WHO) guidelines. Laboratory tests, Electroencephalography (EEG), and Magnetic Resonance Imaging (MRI) were performed. There was no statistically significant difference in the Neutrophil-Lymphocyte Ratio (NLR), C-reactive protein (CRP), and Interleukin 6 (IL-6) in patients who reported to the hospital within a week from the symptoms' onset and in those who reported later. In total, 49.06% of patients with eligible EEG recordings presented abnormal brain activity, while 27.59% of the study population had COVID-19-associated MRI findings. EEG and MRI abnormality occurrence did not correlate with the incidence of mild neurological symptoms (headache, olfactory, and gustatory disorders) of the SARS-CoV-2 infection. In three patients in this study population, unprovoked generalized epileptic seizures occurred for the first time in their life. Non-severe SARS-CoV-2 infection causes functional and structural abnormalities within the central nervous system. Brain microhemorrhages are frequently present in non-severe COVID-19 patients. There is no significant association between mild neurological symptoms of COVID-19 and additional test abnormalities. The time from SARS-CoV-2 infection's onset to hospital admission does not seem to influence the prognostic value of CRP, IL-6, and NLR in non-severe COVID-19. Mild-to-moderate SARS-CoV-2 infection can be a trigger factor for epilepsy and epileptic seizures.

Efficacy of blood urea nitrogen-to-albumin ratio for predicting prognostic outcomes of inpatients with COVID-19: A meta-analysis

BACKGROUND

The associations between blood urea nitrogen (BUN)/albumin ratio and poor prognosis in patients with diagnosis of coronavirus disease 2019 (COVID-19) remain to be clarified.

METHODS

A search based on 4 electronic databases (i.e., EMBASE, Google scholar, MEDLINE, and Cochrane Library) was performed on June 23, 2022. The association of BUN/Albumin ratio with poor prognostic outcomes, defined as patients with mortality/severe illnesses, were analyzed.

RESULTS

Results from analysis of 7 cohort studies (3600 individuals with COVID-19) published between 2020 and 2022 showed a higher BUN/Albumin ratio in the poor-prognosis group (Mean difference:  = 2.838, 95% confidence interval: 2.015-3.66, P < .001, I2 = 92.5%) than the good-prognosis group. Additional investigation into the connection between BUN/Albumin ratio as a binary variable (i.e., high or low) and the risk of poor outcome also supported an association between a higher BUN/Albumin ratio and a poor prognostic risk (odd ratio = 3.009, 95% confidence interval: 1.565-5.783, P = .001, I2 = 93.7%, 5 studies). Merged analysis of poor prognosis produced a sensitivity of 0.76, specificity of 0.72, and area under curve of 0.81.

CONCLUSION

This meta-analysis demonstrated a positive correlation between BUN/albumin ratio and poor outcome in patients with COVID-19. Additional large-scale prospective studies are needed to verify our findings.

Serial Changes in Blood-Cell-Count-Derived and CRP-Derived Inflammatory Indices of COVID-19 Patients

The aim of the study was to investigate the serial changes in inflammatory indices derived from blood cell counts and C-reactive protein (CRP) levels in COVID-19 patients with good and poor outcomes. We retrospectively analyzed the serial changes in the inflammatory indices in 169 COVID-19 patients. Comparative analyses were performed on the first and last days of a hospital stay or death and serially from day 1 to day 30 from the symptom onset. On admission, non-survivors had higher CRP to lymphocytes ratio (CLR) and multi-inflammatory index (MII) values than survivors, while at the time of discharge/death, the largest differences were found for the neutrophil to lymphocyte ratio (NLR), systemic inflammation response index (SIRI), and MII. A significant decrease in NLR, CLR, and MII by the time of discharge was documented in the survivors, and a significant increase in NLR was documented in the non-survivors. The NLR was the only one that remained significant from days 7-30 of disease in intergroup comparisons. The correlation between the indices and the outcome was observed starting from days 13-15. The changes in the index values over time proved to be more helpful in predicting COVID-19 outcomes than those measured on admission. The values of the inflammatory indices could reliably predict the outcome no earlier than days 13-15 of the disease.

Complement activation predicts negative outcomes in COVID-19: The experience from Northen Italian patients

Coronavirus disease 19 (COVID-19) may present as a multi-organ disease with a hyperinflammatory and prothrombotic response (immunothrombosis) in addition to upper and lower airway involvement. Previous data showed that complement activation plays a role in immunothrombosis mainly in severe forms. The study aimed to investigate whether complement involvement is present in the early phases of the disease and can be predictive of a negative outcome. We enrolled 97 symptomatic patients with a positive RT-PCR for SARS-CoV-2 presenting to the emergency room. The patients with mild symptoms/lung involvement at CT-scan were discharged and the remaining were hospitalized. All the patients were evaluated after a 4-week follow-up and classified as mild (n. 54), moderate (n. 17) or severe COVID-19 (n. 26). Blood samples collected before starting any anti-inflammatory/immunosuppressive therapy were assessed for soluble C5b-9 (sC5b-9) and C5a plasma levels by ELISA, and for the following serum mediators by ELLA: IL-1β, IL-6, IL-8, TNFα, IL-4, IL-10, IL-12p70, IFNγ, IFNα, VEGF-A, VEGF-B, GM-CSF, IL-2, IL-17A, VEGFR2, BLyS. Additional routine laboratory parameters were measured (fibrin fragment D-dimer, C-reactive protein, ferritin, white blood cells, neutrophils, lymphocytes, monocytes, platelets, prothrombin time, activated partial thromboplastin time, and fibrinogen). Fifty age and sex-matched healthy controls were also evaluated. SC5b-9 and C5a plasma levels were significantly increased in the hospitalized patients (moderate and severe) in comparison with the non-hospitalized mild group. SC5b9 and C5a plasma levels were predictive of the disease severity evaluated one month later. IL-6, IL-8, TNFα, IL-10 and complement split products were higher in moderate/severe versus non-hospitalized mild COVID-19 patients and healthy controls but with a huge heterogeneity. SC5b-9 and C5a plasma levels correlated positively with CRP, ferritin values and the neutrophil/lymphocyte ratio. Complement can be activated in the very early phases of the disease, even in mild non-hospitalized patients. Complement activation can be observed even when pro-inflammatory cytokines are not increased, and predicts a negative outcome.

COVID19 biomarkers: What did we learn from systematic reviews?

The coronavirus disease 2019 (COVID19) pandemic continues to represent a substantial public health concern. It can rapidly progress to severe disease, with poor prognosis and a high mortality risk. An early diagnosis and specific prognostic tools can help healthcare providers to start interventions promptly, understand the likely prognosis and to identify and treat timely individuals likely to develop severe disease with enhanced mortality risk. Here we focused on an impressive set of systematic reviews and meta-analyses that were performed since the start of the COVID19 pandemic and summarized their results related to the levels of hematologic, inflammatory, immunologic biomarkers as well as markers of cardiac, respiratory, hepatic, gastrointestinal and renal systems and their association with the disease progression, severity and mortality. The evidence outlines the significance of specific biomarkers, including inflammatory and immunological parameters (C-reactive protein, procalcitonin, interleukin-6), hematological (lymphocytes count, neutrophil-to-lymphocyte ratio, D-dimer, ferritin, red blood cell distribution width), cardiac (troponin, CK-MB, myoglobin), liver (AST, ALT, total bilirubin, albumin) and lung injury (Krebs von den Lungen-6) that can be used as prognostic biomarkers to aid the identification of high-risk patients and the prediction of serious outcomes, including mortality, in COVID19. Thus, these parameters should be used as essential tools for an early risk stratification and adequate intervention in improving disease outcomes in COVID19 patients.

The Value of Early and Follow-Up Elevated Scores Based on Peripheral Complete Blood Cell Count for Predicting Adverse Outcomes in COVID-19 Patients

Background: The ongoing COVID-19 pandemic has put a constant strain on hospital resources, so there is a dire need for investigation methods that are widely available and that can predict mortality and the need for critical care. Hematological indices, which can be easily calculated from a complete blood count (CBC), are useful in determining a patient’s inflammatory response to infectious diseases. Aim: This was a prospective cohort study that aimed to assess the prognostic value of scores based on CBCs in hospitalized patients with mild or moderate COVID-19 and medical comorbidities regarding the need for intensive care unit (ICU) therapy and short-term mortality. Methods: We included 607 patients with confirmed COVID-19, followed up for the need for ICU admission (15.5%) and 30 day mortality post-discharge (21.7%). CBC-derived scores were tested upon emergency department (ED) admission and after a median of 8 days. Results: In a multivariate model, elevated followed-up neutrophil-to-lymphocyte ratio (NLR) predicted increased odds for ICU admission (OR: 1.14 [95%CI: 1.06−1.22], p < 0.001) and short-term mortality (OR: 1.30 [95%CI: 1.09−1.57], p = 0.005). Monocyte-to-lymphocyte ratio (MLR) predicted 2.5-fold increased odds for ICU admission and 2.2-fold increased odds for mortality. Conclusion: NLR and MLR followed up 8 days post-admission are predictive for adverse outcomes in mild or moderate COVID-19 patients.

Transcriptional dynamics of granulocytes in direct response to incubation with SARS-CoV-2

Severe coronavirus disease 2019 (COVID-19) is characterized by acute respiratory distress syndrome and multiple organ dysfunction, in which the host immune response plays a pivotal role. Excessive neutrophil activation and subsequent superfluity of neutrophil extracellular traps (NETs) can lead to tissue damage, and several studies have shown the involvement of neutrophils in severe COVID-19. However, the detailed responses of each neutrophil subset to SARS-CoV-2 infection has not been fully described. To explore this issue, we incubated normal-density granulocytes (NDGs) and low-density granulocytes (LDGs) with different viral titers of SARS-CoV-2. NDGs form NETs with chromatin fibers in response to SARS-CoV-2, whereas LDGs incubated with SARS-CoV-2 display a distinct morphology with condensed nuclei and moderate transcriptional changes. Based on these transcriptional changes, we suggest that AGO2 possibly plays a role in LDG regulation in response to SARS-CoV-2.

Validation of the T-Lymphocyte Subset Index (TLSI) as a Score to Predict Mortality in Unvaccinated Hospitalized COVID-19 Patients

Lymphopenia has been consistently reported as associated with severe coronavirus disease 2019 (COVID-19). Several studies have described a profound decline in all T-cell subtypes in hospitalized patients with severe and critical COVID-19. The aim of this study was to assess the role of T-lymphocyte subset absolute counts measured at ward admission in predicting 30-day mortality in COVID-19 hospitalized patients, validating a new prognostic score, the T-Lymphocyte Subset Index (TLSI, range 0−2), based on the number of T-cell subset (CD4+ and CD8+) absolute counts that are below prespecified cutoffs. These cutoff values derive from a previously published work of our research group at Policlinico Tor Vergata, Rome, Italy: CD3+CD4+ < 369 cells/μL, CD3+CD8+ < 194 cells/μL. In the present single-center retrospective study, T-cell subsets were assessed on admission to the infectious diseases ward. Statistical analysis was performed using JASP (Version 0.16.2. JASP Team, 2022, Amsterdam, The Netherlands) and Prism8 (version 8.2.1. GraphPad Software, San Diego, CA, USA). Clinical and laboratory parameters of 296 adult patients hospitalized because of COVID-19 were analyzed. The overall mortality rate was 22.3% (66/296). Survivors (S) had a statistically significant lower TLSI score compared to non-survivors (NS) (p < 0.001). Patients with increasing TLSI scores had proportionally higher rates of 30-day mortality (p < 0.0001). In the multivariable logistic analysis, the TLSI was an independent predictor of in-hospital 30-day mortality (OR: 1.893, p = 0.003). Survival analysis showed that patients with a TLSI > 0 had an increased risk of death compared to patients with a TLSI = 0 (hazard ratio: 2.83, p < 0.0001). The TLSI was confirmed as an early and independent predictor of COVID-19 in-hospital 30-day mortality.

White Blood Cells, COVID-19, and Mendelian Randomization

Many observational studies have shown an association between the severity of COVID-19 and the different white blood cell counts, most frequently neutrophils, lymphocytes, and eosinophils. The studies aimed to predict the prognosis, and therefore, a causal relationship was unnecessary. However, if we begin to look at these biomarkers as potential therapeutic targets, then causality is essential. Observational studies cannot prove a causal relationship, and randomized trials are not always feasible. In this case, Mendelian randomization studies, considered more valid than observational studies, could add to the arguments for causality. Two Mendelian randomization studies tested for a causal relationship between the number of different white cell populations and COVID-19 severity, but their results are different; therefore, the problem of causality is not settled in this case.

Case report: COVID-19 infection in a pregnant 33-year-old kidney transplant recipient

Patients facing severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infections with comorbidities, especially patients whose immune system is weakened have higher chances to face severe outcomes. One of the main reasons behind the suppression of the immune system is iatrogenic, in patients who have autoimmune diseases and/or had an organ transplant. Although there are studies that are examining immunocompromised and/or transplanted patients with COVID-19 infection, furthermore there is a limited number of studies available which are dealing with COVID-19 in pregnant women; however, it is unique and is worth reporting when these factors are coexisting. In this study, we present the case of a 33-year-old Caucasian pregnant woman, who had a kidney transplant in 2009 and contracted the SARS-CoV-2 virus on the 26th gestational week, in 2021. After her infection, superimposed preeclampsia was diagnosed and due to the worsening flowmetric parameters, she gave birth to a premature male newborn with cesarean section. Our kidney transplant patient’s case highlights how COVID-19 disease can lead to preeclampsia and artificial termination of gestation.

Comparative analysis of neutrophil to lymphocyte ratio and derived neutrophil to lymphocyte ratio with respect to outcomes of in-hospital coronavirus disease 2019 patients: A retrospective study

Introduction and objectives

In patients with coronavirus disease 2019 (COVID-19), several abnormal hematological biomarkers have been reported. The current study aimed to find out the association of neutrophil to lymphocyte ratio (NLR) and derived NLR (dNLR) with COVID-19. The objective was to compare the accuracy of both of these markers in predicting the severity of the disease.

Materials and methods

The study was conducted in a single-center having patients with COVID-19 with a considerable hospital stay. NLR is easily calculated by dividing the absolute neutrophil count (ANC) with the absolute lymphocyte count (ALC) {ANC/ALC}, while dNLR is calculated by ANC divided by total leukocyte count minus ANC {ANC/(WBC-ANC)}. Medians and interquartile ranges (IQR) were represented by box plots. Multivariable logistic regression was performed obtaining an odds ratio (OR), 95% CI, and further adjusted to discover the independent predictors and risk factors associated with elevated NLR and dNLR.

Results

A total of 1,000 patients with COVID-19 were included. The baseline NLR and dNLR were 5.00 (2.91–10.46) and 4.00 (2.33–6.14), respectively. A cut-off value of 4.23 for NLR and 2.63 for dNLR were set by receiver operating characteristic (ROC) analysis. Significant associations of NLR were obtained by binary logistic regression for dependent outcome variables as ICU stay (p < 0.001), death (p < 0.001), and invasive ventilation (p < 0.001) while that of dNLR with ICU stay (p = 0.002), death (p < 0.001), and invasive ventilation (p = 0.002) on multivariate analysis when adjusted for age, gender, and a wave of pandemics. Moreover, the indices were found correlating with other inflammatory markers such as C-reactive protein (CRP), D-dimer, and procalcitonin (PCT).

Conclusion

Both markers are equally reliable and sensitive for predicting in-hospital outcomes of patients with COVID-19. Early detection and predictive analysis of these markers can allow physicians to risk assessment and prompt management of these patients.

Características clínicas, imagenológicas y de laboratorio de pacientes con COVID-19 según requerimiento de ingreso a UCI en Cali, Colombia

Introducción. Actualmente, hay pocos estudios en Latinoamérica sobre las características demográficas, clínicas y de laboratorio de pacientes con COVID-19 y con requerimiento de ingreso a unidad de cuidados intensivos (UCI). Objetivo. Comparar las características sociodemográficas, clínicas, imagenológicas y de laboratorio de pacientes diagnosticados con COVID-19 atendidos en el servicio de urgencias de una clínica en Cali, Colombia, según requerimiento de ingreso a UCI. Materiales y métodos. Estudio retrospectivo descriptivo de cohorte única realizado en 49 adultos con COVID-19 atendidos en el servicio de urgencias de un hospital de cuarto nivel de atención en Cali, Colombia, en marzo y abril de 2020, los cuales se dividieron en dos grupos: requerimiento de UCI (n=24) y no requerimiento de UCI (n=25). Se realizaron análisis bivariados para determinar las diferencias entre ambos grupos (pruebas de chi-2, exacta de Fisher, t de Student y U de Mann-Whitney), con un nivel de significancia de p<0.05. Resultados. La edad promedio fue 53 años (DE=13) y 29 pacientes fueron hombres. Se encontraron diferencias significativas entre ambos grupos en las siguientes variables: edad promedio (UCI x̅=58 vs. No UCI x̅=49; p=0.020), presencia de diabetes (8 vs. 1; p=0.010), presencia de dificultad respiratoria (20 vs. 11; p=0.007), presencia uni o bilateral de áreas de consolidación (12 vs. 3; p=0.005), mediana del conteo de leucocitos (Med=7570/mm3 vs. Med=5130/mm3; p=0.0013), de neutrófilos (Med=5980/mm3 vs. Med=3450/mm3; p=0,0001) y linfocitos (Med=865/mm3 vs. Med=1400/mm3; p<0,0001), mediana de proteína C reactiva (Med=141,25mg/L vs. Med=27,95mg/L; p<0,001), ferritina (Med=1038ng/L vs. Med=542,5ng/L; p=0.0073) y lactato-deshidrogenasa (Med=391U/L vs, Med=248,5U/L, p=0,0014). Finalmente, 15 pacientes requirieron ventilación mecánica invasiva, 2 presentaron extubación fallida, y en total, 5 fallecieron. Conclusiones. Se observaron diferencias significativas en los valores de varios marcadores inflamatorios, daño celular y parámetros del hemograma entre los pacientes que requirieron admisión a la UCI y los que no, por lo que estas variables podrían emplearse para desarrollar herramientas que contribuyan a establecer el pronóstico de esta enfermedad.

A high neutrophil to lymphocyte ratio at ICU admission is associated with nutritional risk in COVID-19 patients

Background

Inflammation plays a crucial role in nutrition status and can be useful in early nutrition risk screening of patients during the coronavirus disease 2019 (COVID‐19) pandemic. Thus, this study aimed to assess the association between systemic inflammatory markers and nutrition risk tools in intensive care unit (ICU) patients with COVID‐19.

Methods

Patients with confirmed COVID‐19 and ICU admission were enrolled in a retrospective, observational, cross‐sectional study. The medians of C‐reactive protein (CRP; ≥13.8 mg/dl) and the neutrophil‐to‐lymphocyte ratio (NLR; ≥12.6) upon admission were used to dichotomize patients.

Results

Of the 73 patients, 63% were men; the average age was 56 years, and the median length of hospital stay was 10 (25th: 4; 75th: 17) days. When nutrition risk screening tools were used, 85% were at risk according to Nutritional Risk Screening (≥3 points), whereas 42% had high risk according to the Modified Nutrition Risk in the Critically Ill (mNUTRIC; ≥5 points), and 57% were moderately or severely malnourished according to the Subjective Global Assessment (B or C). Mortality was higher in the group with NLR ≥12.6 than in the group with NLR <12.6, with no difference between CRP groups. A significant association was found only between NLR and mNUTRIC, even when adjusted by sex, age, and body mass index (odds ratio, 1.36; 95% CI, 1.06–1.76; P = 0.016), but not between CRP and nutrition risk.

Conclusion

Although the inflammatory marker CRP is the most used in hospital clinical practice, we found that only NLR was associated with nutrition risk (NUTRIC score).