ABSTRACT
Severe coronavirus disease 2019 (COVID-19) is associated with an overactive inflammatory response mediated by macrophages. Here, we analyzed the phenotype and function of neutrophils in patients with COVID-19. We found that neutrophils from patients with severe COVID-19 express high levels of CD11b and CD66b, spontaneously produce CXCL8 and CCL2, and show a strong association with platelets. Production of CXCL8 correlated with plasma concentrations of lactate dehydrogenase and D-dimer. Whole blood assays revealed that neutrophils from patients with severe COVID-19 show a clear association with immunoglobulin G (IgG) immune complexes. Moreover, we found that sera from patients with severe disease contain high levels of immune complexes and activate neutrophils through a mechanism partially dependent on FcγRII (CD32). Interestingly, when integrated in immune complexes, anti-severe acute respiratory syndrome coronavirus 2 IgG antibodies from patients with severe COVID-19 displayed a higher proinflammatory profile compared with antibodies from patients with mild disease. Our study suggests that IgG immune complexes might promote the acquisition of an inflammatory signature by neutrophils, worsening the course of COVID-19.
Subject(s)
Antibodies, Viral/immunology , Antigen-Antibody Complex/immunology , COVID-19/immunology , Immunoglobulin G/immunology , Neutrophil Activation/immunology , Adult , Aged , Antibodies, Viral/blood , Antigen-Antibody Complex/blood , Antigens, CD/immunology , CD11b Antigen/immunology , Cell Adhesion Molecules/immunology , Female , GPI-Linked Proteins/immunology , Humans , Immunoglobulin G/blood , Interleukin-8/immunology , Male , Middle Aged , Neutrophils/immunology , Receptors, IgG/immunology , SARS-CoV-2/immunology , Young AdultABSTRACT
BACKGROUND: Severe pneumonia is the most common cause of intensive care unit (ICU) admission and death due to novel coronavirus (SARS-CoV-2) respiratory disease (COVID-19). Due to its rapid outbreak, units for the evaluation of febrile patients in the pre-hospital setting were created. OBJECTIVE: The objective of the study was to develop a sensitive and simple tool to assess the risk of pneumonia in COVID-19 patients and thus select which patients would require a chest imaging study. MATERIALS AND METHODS: We conducted a cross-sectional study in a cohort of individuals with suspected COVID-19 evaluated in a public academic healthcare center in Buenos Aires city. All adult patients with positive RT-PCR assay for SARS-COV2 between April 24 and May 19 of 2020 were included in the study. Pneumonia was defined as the presence of compatible signs and symptoms with imaging confirmation. Univariate and multivariate logistic regression was performed. A risk indicator score was developed. RESULTS: One hundred and forty-eight patients were included, 71 (48%) received the diagnosis of pneumonia. The final clinical model included four variables: age >- 40 years, cough, absence of sore throat, and respiratory rate >- 22. To create the score, we assigned values to the variables according to their ORs: 2 points for respiratory rate >- 22 and 1 point to the other variables. The AUC of the ROC curve was 0.80 (CI 95% 0.73-0.86). A cutoff value of 2 showed a sensitivity of 95.7% and a specificity of 43.24%. CONCLUSION: This sensible score may improve the risk stratification of COVID-19 patients in the pre-hospital setting.