A Complement Atlas identifies interleukin 6 dependent alternative pathway dysregulation as a key druggable feature of COVID-19 (preprint)

To improve COVID-19 therapy, it is essential to understand the mechanisms driving critical illness. The complement system is an essential part of innate host defense that can also contribute to injury. All complement pathways have been implicated in COVID-19 pathogenesis, however the upstream drivers and downstream consequences on tissue injury remain ill-defined. Here, we demonstrate that complement activation is mediated by the alternative pathway and we provide a comprehensive atlas of the alterations in complement around the time of respiratory deterioration. Proteome and single-cell sequencing mapping across cell types and tissues reveals a division of labor between lung epithelial, stromal and myeloid cells in the production of complement, in addition to liver-derived factors. Upstream, IL-6 drives complement responses, linking complement dysregulation to approved COVID-19 therapies. In an exploratory proteomic study, C5 inhibition improves epithelial damage and markers of disease severity. Collectively, these results identify complement dysregulation as a key druggable feature of COVID-19.

Early treatment with inhaled GM-CSF improves oxygenation and anti-viral immunity in COVID-19 induced lung injury – a randomized clinical trial (preprint)

Granulocyte-macrophage colony-stimulating factor (GM-CSF) instructs monocytes to differentiate into alveolar macrophages (AM) that preserve lung homeostasis. By comparing AM development in mouse and human, we discovered that COVID-19 patients showed marked defects in GM-CSF-dependent AM instruction. The multi-center, open-label, randomized, controlled SARPAC-trial evaluated the efficacy and safety of 5 days of inhalation of rhu-GM-CSF (sargramostim, Leukine®) in 81 non-ventilated patients with COVID-19 and hypoxemic respiratory failure identified by PaO2/FiO2 ratio < 350mmHg. At day 6, more patients in the sargramostim group experienced at least 25% improvement in oxygenation compared with the standard of care group. Higher numbers of circulating class-switched B cells and effector virus-specific CD8 lymphocytes were found in the sargramostim group. Treatment adverse events, including signs of cytokine storm, were not different between active and control group. This proof-of-concept study demonstrates the feasibility and safety of inhaled GM-CSF in restoring alveolar gas exchange, while simultaneously boosting anti-COVID-19 immunity. ClinicalTrials.gov (NCT04326920).

Essentials in saline pharmacology for nasal or respiratory hygiene in times of COVID-19 (preprint)

Purpose: Nasal irrigation or nebulizing aerosol of isotonic or hypertonic saline is a traditional method for respiratory or nasal care. A recent small study in outpatients with COVID-19 without acute respiratory distress syndrome suggests substantial symptom resolution. We therefore analysed pharmacological/pharmacodynamic effects of isotonic or hypertonic saline, relevant to SARS-CoV-2 infection and respiratory care.Methods: Progressive and systematic searches.Results: Due to its wetting properties, saline achieves an improved spreading of alveolar lining fluid and has been shown to reduce bio-aerosols and viral load. Saline provides moisture to respiratory epithelia and gels mucus, promotes ciliary beating and improves mucociliary clearance. Coronaviruses and SARS-CoV-2 damage ciliated epithelium in the nose and airways. Saline inhibits SARS-CoV-2 replication in Vero cells; possible interactions involve the viral ACE2-entry mechanism (chloride-dependent ACE2 configuration) and sodium channel ENaC. Saline shifts myeloperoxidase activity in epithelial or phagocytic cells to produce hypochlorous acid. Clinically, nasal or respiratory airway care with saline reduces symptoms of seasonal coronaviruses and other common cold viruses. Its use as aerosol reduces hospitalisation rates for respiratory syncytial virus infection in children. Preliminary data suggest symptom reduction in symptomatic COVID-19 patients if saline is initiated within 48 hours of symptom onset.Conclusions: Saline interacts at various levels relevant to nasal or respiratory hygiene (nasal irrigation or aerosol). If used from the onset of common cold symptoms, it may represent a useful add-on to first-line interventions for COVID-19. Formal evaluation in mild COVID-19 is desirable as to establish efficacy and optimal treatment regimens.

Multisystem inflammatory syndrome in children related to COVID-19: A systematic review (preprint)

ImportanceIn April 2020, multiple reports of an association between a hyperinflammatory, Kawasaki-like condition and SARS-CoV-2 were published and termed as pediatric inflammatory multisystem syndrome (PIMS) or multisystem inflammatory syndrome (MIS). A thorough characterization of this syndrome (demographics, presentation, diagnosis, and outcome) is currently lacking. ObjectiveWe aimed to perform a systematic review of published cases of this novel multisystem inflammatory syndrome in children associated with COVID-19. Evidence reviewA literature search of Pubmed, Embase, BioRxiv, MedRxiv and COVID-19 specific research repositories (Cochrane COVID-19 Study Register and the World Health Organization (WHO) COVID-19 Global Research Database) was conducted from December 30th, 2019 to June 30th, 2020. Publications describing inflammatory syndromes associated with COVID-19 were included. Of 333 unique publications, 229 records were excluded based on title and abstract. After screening the full text, 40 observational studies and case reports were included, comprising 687 cases (published between May 9th, 2020 and June 30th, 2020). FindingsIn contrast to classic Kawasaki disease, epidemiological enrichment for adolescents (median age 9 [6.0-12.3]) and ethnic minorities (35.8% black and 24.5% Hispanic/Latino) was observed. There was a male predominance (59.1%). Apart from obesity (24.4%), pre-existing conditions were infrequent. The majority suffered from gastrointestinal (87.2%) and cardiocirculatory (79.2%) manifestations. Respiratory symptoms (51.2%) were less frequent. Over half of patients (56.3%) presented with hemodynamic shock, and critical care interventions were often necessary (inotropics (56.5%), mechanical ventilation (22.9%), non-invasive ventilation (30.6%), extracorporal membrane oxygenation (ECMO;4.5%)). Anti-SARS-CoV-2 IgG and RT-PCR were positive in respectively 69.4% and 36.7%. Eleven deaths were reported (1.6%). The RCPCH case definition proved to be most comprehensive comprising all single cases. In contrast, WHO and CDC MIS definitions are more stringent, with the CDC case definition often missing severe cases requiring intensive care (n = 33 out of 95 cases). Conclusions and RelevanceThis novel pediatric multisystem hyperinflammatory condition, associated with COVID-19, is characterized by a severe and heterogeneous disease spectrum. Despite frequent intensive care interventions, mortality rate was low and short-term outcome favorable. Long-term follow-up of possible chronic complications and additional clinical research, to elucidate the underlying immunological pathogenesis and possible genetic predisposition is crucial. Key pointsO_ST_ABSQuestionC_ST_ABSHow is the novel pediatric multisystem inflammatory condition associated with coronavirus disease 2019 (COVID-19) characterized? FindingsThis systematic review of 40 studies, comprising 687 cases, represents the heterogeneous spectrum of this novel pediatric disease related to COVID-19, including contrasting features with previously-described hyperinflammatory conditions. Adolescents and particular racial/ethnic minorities are affected more. Gastrointestinal and cardiocirculatory manifestations are often found, along with critical care interventions. Nevertheless, only 11 deaths are reported. MeaningThis novel condition has variable severity but good short-term outcome. Uniform case definitions are required to guide future (preferably controlled) research on epidemiological clustering, immunopathology, and long-term prognosis.