Discrimination of COVID-19 From Inflammation-Induced Cytokine Storm Syndromes Using Disease-Related Blood Biomarkers.

OBJECTIVE: Infection with the novel coronavirus SARS-CoV-2 triggers severe illness with high mortality in a subgroup of patients. Such a critical course of COVID-19 is thought to be associated with the development of cytokine storm, a condition seen in macrophage activation syndrome (MAS) and secondary hemophagocytic lymphohistiocytosis (HLH). However, specific data demonstrating a clear association of cytokine storm with severe COVID-19 are still lacking. The aim of this study was to directly address whether immune activation in COVID-19 does indeed mimic the conditions found in these classic cytokine storm syndromes. METHODS: Levels of 22 biomarkers were quantified in serum samples from patients with COVID-19 (n = 30 patients, n = 83 longitudinal samples in total), patients with secondary HLH/MAS (n = 50), and healthy controls (n = 9). Measurements were performed using bead array assays and single-marker enzyme-linked immunosorbent assay. Serum biomarker levels were assessed for correlations with disease outcome. RESULTS: In patients with secondary HLH/MAS, we observed pronounced activation of the interleukin-18 (IL-18)-interferon-γ axis, increased serum levels of IL-1 receptor antagonist, intercellular adhesion molecule 1, and IL-8, and strongly reduced levels of soluble Fas ligand in the course of SARS-CoV-2 infection. These observations appeared to discriminate immune dysregulation in critical COVID-19 from the well-recognized characteristics of other cytokine storm syndromes. CONCLUSION: Serum biomarker profiles clearly separate COVID-19 from MAS or secondary HLH in terms of distinguishing the severe systemic hyperinflammation that occurs following SARS-CoV-2 infection. These findings could be useful in determining the efficacy of drugs targeting key molecules and pathways specifically associated with systemic cytokine storm conditions in the treatment of COVID-19.

Covid-19 and blood groups: ABO antibody levels may also matter.

BACKGROUND: Susceptibility to Covid-19 has been found to be associated with the ABO blood group, with O type individuals being at a lower risk. However, the underlying mechanism has not been elucidated. Here, we aimed to test the hypothesis that Covid-19 patients might have lower levels of ABO antibodies than non-infected individuals as they could offer some degree of protection. METHODS: After showing that the viral spike protein harbors the ABO glycan epitopes when produced by cells expressing the relevant glycosyltransferases, like upper respiratory tract epithelial cells, we enrolled 290 patients with Covid-19 and 276 asymptomatic controls to compare their levels of natural ABO blood group antibodies. RESULTS: We found significantly lower IgM anti-A + anti-B agglutination scores in blood group O patients (76.93 vs 88.29, P-value = 0.034) and lower levels of anti-B (24.93 vs 30.40, P-value = 0.028) and anti-A antibodies (28.56 vs 36.50, P-value = 0.048) in blood group A and blood group B patients, respectively, compared to controls. CONCLUSION: In this study, we showed that ABO antibody levels are significantly lower in Covid-19 patients compared to controls. These findings could indicate that patients with low levels of ABO antibodies are at higher risk of being infected.

Interleukine-6 in critically ill COVID-19 patients: A retrospective analysis.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) appeared in China in December 2019 and has spread around the world. High Interleukin-6 (IL-6) levels in COVID-19 patients suggest that a cytokine storm may play a major role in the pathophysiology and are considered as a relevant parameter in predicting most severe course of disease. The aim of this study was to assess repeated IL-6 levels in critically ill COVID-19 patients admitted to our Intensive Care Unit (ICU) and to evaluate their relationship with patient's severity and outcome. METHODS: We conducted a retrospective study on patients admitted to the ICU with a diagnosis of COVID-19 between March 10 (i.e. the date of the first admitted patients) and April 30, 2020. Demographic, clinical and laboratory data were collected at admission. On the day of IL-6 blood concentration measurement, we also collected results of D-Dimers, C-Reactive Protein, white blood cells and lymphocytes count, lactate dehydrogenase (LDH) and ferritin as well as microbiological samples, whenever present. RESULTS: Of a total of 65 patients with COVID-19 admitted to our ICU we included 41 patients with repeated measure of IL-6. There was a significant difference in IL-6 levels between survivors and non-survivors over time (p = 0.001); moreover, non survivors had a significantly higher IL-6 maximal value when compared to survivors (720 [349-2116] vs. 336 [195-646] pg/mL, p = 0.01). The IL-6 maximal value had a significant predictive value of ICU mortality (AUROC 0.73 [95% CI 0.57-0.89]; p = 0.01). CONCLUSIONS: Repeated measurements of IL-6 can help clinicians in identifying critically ill COVID-19 patients with the highest risk of poor prognosis.

A score combining early detection of cytokines accurately predicts COVID-19 severity and intensive care unit transfer.

OBJECTIVES: We aimed to explore cytokine profile in patients as it relates to Coronavirus Disease 2019 (COVID-19) severity, and to establish a predictive cytokine score to discriminate severe from non-severe cases and provide a prognosis parameter for patients that will require intensive care unit (ICU) transfer. METHODS: Serum samples of 63 patients diagnosed with SARS-CoV-2 infection were collected early after hospital admission (day 0-3). Patients were categorized in five groups based on the clinical presentation, the PaO2/FiO2 ratio and the requirement of mechanical ventilation. RESULTS: Three cytokines, IL-6, IL-8 and IL-10, were markedly higher in severe forms (n = 44) than in non-severe forms (n = 19) (p < 0.005). A score combining levels of these three cytokines (IL-6*IL-8*IL-10) had the highest performance to predict severity: sensitivity of 86.4% (95% CI, 72.4-94.8) and specificity of 94.7% (95% CI, 74.0-99.9) for a cutoff value of 2068 pg/mL. Elevated levels of IL-6, IL-8 and IL-10 were also found in critically ill patients. The combination of IL-6*IL-10 serum levels allowed the highest predictability for ICU transfer: AUC of 0.898 (p < 0.0001). CONCLUSION: The combinatorial IL-6*IL-8*IL-10 score at presentation was highly predictive of the progression to a severe form of the disease, and could contribute to improve patient triage and to adapt therapeutic strategy within clinical trials more accurately and efficiently.