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BackgroundAcute respiratory distress syndrome (ARDS) is the major cause of death in coronavirus disease 2019 (COVID-19). Multiple autopsy-based reports of COVID-19 lung pathology describe diffuse alveolar damage (DAD), organizing pneumonia (OP) and fibrotic change, but data on early pathological changes as well as during progression of the disease are rare. Research questionComparison of histopathological and ultrastructural findings in paired transbronchial biopsies (TBBs) and autopsy material from three patients with confirmed SARS-CoV-2-infection. MethodsWe prospectively enrolled 3 patients with confirmed SARS-CoV-2 infection. Full clinical evaluation was performed including high-resolution computed tomography (HR-CT). We took TBBs at different time points during the disease and autopsy tissue samples after the patients death. ResultsSARS-CoV-2 was detected by RT-PCR and/or FISH in all TBBs. Lung histology revealed pneumocyte hyperplasia and capillary congestion in one patient who died short after hospital admission with detectable virus in 1/2 autopsy samples from the lung. SARS-CoV-2 was detected in 2/2 autopsy samples from a patient with a fulminant course of the disease and very short latency between biopsy and autopsy, both showing widespread DAD. In a third patient with a prolonged course, i.e. five weeks of ICU treatment with ECMO, autopsy samples showed extensive interstitial fibrosis without detectable virus by RT-PCR and/or FISH. InterpretationWe report the course of COVID-19 in paired TBB and autopsy samples from three patients at an early stage, in rapidly progressive and in a prolonged disease course. Our findings illustrate vascular, organizing and fibrotic patterns of COVID-19-induced lung injury and suggest an early spread of SARS-CoV-2 from the upper airways to the lung periphery with diminishing viral load during disease.
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BackgroundUnderstanding the pathophysiology of respiratory failure (ARDS) in coronavirus disease 2019 (COVID-19) patients is of utmost importance for the development of therapeutic strategies and identification of risk factors. Since we observed clinical and histopathological similarities between COVID-19 and lung manifestations of connective tissue disease (CTD-ILD) in our clinical practice, aim of the present study is to analyze a possible role of autoimmunity in SARS-CoV-2-associated respiratory failure. MethodsIn this prospective, single-center trial, we enrolled 22 consecutive patients with RT-PCR-confirmed SARS-CoV-2 infection hospitalized in March and April, 2020. We performed high-resolution computed tomography (HR-CT) and full laboratory testing including autoantibody (AAB) screening (anti-ANA, SS-B/La, Scl-70, Jo-1, CENP-B, PM-Scl). Transbronchial biopsies as well as post mortem tissue samples were obtained from 3 and 2 cases, respectively, and subsequent histopathologic analysis with special emphasis on characterization of interstitial lung disease was performed. ResultsTwelve of 22 patients (54.5%) were male and median age was 69.0 (range: 28-88). 11 (50.0%) patients had to be undergo intensive care unit (ICU) treatment. Intubation with ventilation was required in 10/22 cases (46%). Median follow-up was 26 days. Clinical and serological parameters were comparable to previous reports. Radiological and histopathological findings were highly heterogeneous including patterns reminiscent of CTD-ILD. AAB titers [≥]1:100 were detected in 10/11 (91.9%) COVID-19 patients who required ICU treatment, but in 4/11 (36.4%) patients with mild clinical course (p=0.024). Patients with AABs tended to require invasive ventilation and showed significantly more severe complications (64.3% vs. 12.5%, p=0.031). Overall COVID-19-related mortality was 18.2% among hospitalized patients at our institution. ConclusionOur findings point out serological, radiological and histomorphological similarities between COVID-19-associated ARDS and acute exacerbation of CTD-ILD. While the exact mechanism is still unknown, we postulate that SARS-CoV-2 infection might trigger or simulate a form of organ-specific autoimmunity in predisposed patients. The detection of autoantibodies might identify patients who profit from immunosuppressive therapy to prevent the development of respiratory failure.