Coronavirus Disease 2019 Autopsies Research Articles

A histopathological analysis of extrapulmonary lesions in fatal coronavirus disease (COVID-19)

IntroductionThe coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), presents diverse clinical manifestations and multi-organ involvement. This study aimed to evaluate the extra-pulmonary histopathological patterns underpinning COVID-19-induced lesions in cardiac, hepatic, renal, brainstem, and splenic tissues. Materials and methodsThe research involved conventional forensic autopsies conducted between April 2020 and April 2021 on individuals with confirmed SARS-CoV-2 infection in Cluj-Napoca, Romania. Tissues were processed and stained for histological examination. Differences in patients with and without diffuse alveolar damage (DAD) were evaluated. ResultsIn our study of 79 COVID-19 autopsies conducted on unvaccinated patients besides lung involvement, the patients had histological changes in at least two out of five (brain, heart, liver, kidney, and spleen) organs. Notable findings include hepatitis observed in 46.8 % of cases, 21.5 % with lobular hepatitis, and 41.8 % with liver steatosis. Additionally, 69.6 % exhibited acute tubular necrosis, and 55.7 % had varying degrees of splenic lymphocyte depletion. Almost 41 % of cases had pericardial effusion, 36.7 % myocarditis, 24.1 % myocardial infarction, and 12.7 % of cases had encephalitis. Acute tubular necrosis (78.6 %) was the most frequent histopathological finding observed in patients with DAD. Myocarditis was described in 45.9 % of the patients without DAD. DiscussionThe autopsy findings in our cohort of COVID-19 victims align with international scientific literature. Distinguishing viral-induced myocarditis, encephalitis, hepatitis, or systemic inflammatory syndrome remains challenging. ConclusionPost-mortem analysis identified lesions associated with SARS-CoV-2 in multiple organs, highlighting the systemic nature of the virus and emphasizing the need for continued research into organ-specific damage and long-term sequelae of COVID-19.

Frequency of subclinical interstitial lung disease in COVID-19 autopsy cases: potential risk factors of severe pneumonia

Risk factors of severe coronavirus disease 2019 (COVID-19) have been previously reported; however, histological risk factors have not been defined thus far. The aim of this study was to clarify subclinical hidden interstitial lung disease (ILD) as a risk factor of severe pneumonia associated with COVID-19. We carefully examined autopsied lungs and chest computed tomography scanning (CT) images from patients with COVID-19 for interstitial lesions and then analyzed their relationship with disease severity. Among the autopsy series, subclinical ILD was found in 13/27 cases (48%) in the COVID-19 group, and in contrast, 8/65 (12%) in the control autopsy group (p = 0.0006; Fisher’s exact test). We reviewed CT images from the COVID-19 autopsy cases and verified that subclinical ILD was histologically detectable in the CT images. Then, we retrospectively examined CT images from another series of COVID-19 cases in the Yokohama, Japan area between February–August 2020 for interstitial lesions and analyzed the relationship to the severity of COVID-19 pneumonia. Interstitial lesion was more frequently found in the group with the moderate II/severe disease than in the moderate I/mild disease (severity was evaluated according to the COVID-19 severity classification system of the Ministry of Health, Labor, and Welfare [Japan]) (moderate II/severe, 11/15, 73.3% versus moderate I/mild, 108/245, 44.1%; Fisher exact test, p = 0.0333). In conclusion, it was suggested that subclinical ILD could be an important risk factor for severe COVID-19 pneumonia. A benefit of these findings could be the development of a risk assessment system using high resolution CT images for fatal COVID-19 pneumonia.

Pulmonary Co-Infections Detected Premortem Underestimate Postmortem Findings in a COVID-19 Autopsy Case Series.

Bacterial and fungal co-infections are reported complications of coronavirus disease 2019 (COVID-19) in critically ill patients but may go unrecognized premortem due to diagnostic limitations. We compared the premortem with the postmortem detection of pulmonary co-infections in 55 fatal COVID-19 cases from March 2020 to March 2021. The concordance in the premortem versus the postmortem diagnoses and the pathogen identification were evaluated. Premortem pulmonary co-infections were extracted from medical charts while applying standard diagnostic definitions. Postmortem co-infection was defined by compatible lung histopathology with or without the detection of an organism in tissue by bacterial or fungal staining, or polymerase chain reaction (PCR) with broad-range bacterial and fungal primers. Pulmonary co-infection was detected premortem in significantly fewer cases (15/55, 27%) than were detected postmortem (36/55, 65%; p < 0.0001). Among cases in which co-infection was detected postmortem by histopathology, an organism was identified in 27/36 (75%) of cases. Pseudomonas, Enterobacterales, and Staphylococcus aureus were the most frequently identified bacteria both premortem and postmortem. Invasive pulmonary fungal infection was detected in five cases postmortem, but in no cases premortem. According to the univariate analyses, the patients with undiagnosed pulmonary co-infection had significantly shorter hospital (p = 0.0012) and intensive care unit (p = 0.0006) stays and significantly fewer extra-pulmonary infections (p = 0.0021). Bacterial and fungal pulmonary co-infection are under-recognized complications in critically ill patients with COVID-19.

Post-mortem findings in Spanish patients with COVID-19; a special focus on superinfections.

Whole-body autopsies may be crucial to understand coronavirus disease 2019 (COVID-19) pathophysiology. We aimed to analyze pathological findings in a large series of full-body autopsies, with a special focus on superinfections. This was a prospective multicenter study that included 70 COVID-19 autopsies performed between April 2020 and February 2021. Epidemiological, clinical and pathological information was collected using a standardized case report form. Median (IQR) age was 70 (range 63.75-74.25) years and 76% of cases were males. Most patients (90%,) had at least one comorbidity prior to COVID-19 diagnosis, with vascular risk factors being the most frequent. Infectious complications were developed by 65.71% of the patients during their follow-up. Mechanical ventilation was required in most patients (75.71%) and was mainly invasive. In multivariate analyses, length of hospital stay and invasive mechanical ventilation were significantly associated with infections (p = 0.036 and p = 0.013, respectively). Necropsy findings revealed diffuse alveolar damage in the lungs, left ventricular hypertrophy in the heart, liver steatosis and pre-infection arteriosclerosis in the heart and kidneys. Our study confirms the main necropsy histopathological findings attributed to COVID-19 in a large patient series, while underlining the importance of both comorbid conditions and superinfections in the pathology.

Liver alterations and detection of SARS-CoV-2 RNA and proteins in COVID-19 autopsies

The most severe alterations in Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) infection are seen in the lung. However, other organs also are affected. Here, we report histopathologic findings in the liver and detection of viral proteins and RNA in COVID-19 autopsies performed at the Semmelweis University (Budapest, Hungary). Between March 2020 through March 2022, 150 autopsies on patients who died of COVID-19 were analyzed. Cause-of-death categories were formed based on the association with SARS-CoV-2 as strong, contributive, or weak. Samples for histopathologic study were obtained from all organs, fixed in formalin, and embedded in paraffin (FFPE). Immunohistochemical study (IHC) to detect SARS-CoV-2 spike protein and nucleocapsid protein (NP), CD31, claudin-5, factor VIII, macrosialin (CD68), and cytokeratin 7, with reverse transcriptase polymerase chain reaction (RT-PCR), and in situ hybridization (ISH, RNAscope®) for SARS-CoV-2 RNA were conducted using FFPE samples of livers taken from 20 autopsies performed ≤ 2 days postmortem. All glass slides were scanned; the digital images were evaluated by semiquantitative scoring and scores were analyzed statistically. Steatosis, single-cell and focal/zonal hepatocyte necrosis, portal fibrosis, and chronic inflammation were found in varying percentages. Sinusoidal ectasia, endothelial cell disruption, and fibrin-filled sinusoids were seen in all cases; these were assessed semiquantitatively for severity (SEF scored). SEF scores did not correlate with cause-of-death categories (p = 0.92) or with severity of lung alterations (p = 0.96). SARS-CoV-2 RNA was detected in 13/20 cases by PCR and in 9/20 by ISH, with IHC demonstration of spike protein in 4/20 cases and NP in 15/20. Viral RNA and proteins were located in endothelial and Kupffer cells, and in portal macrophages, but not in hepatocytes and cholangiocytes. In conclusion, endothelial damage (SEF scores) was the most common alteration in the liver and was a characteristic, but not specific alteration in COVID-19, suggesting an important role in the pathogenesis of COVID-19-associated liver disease. Detection of SARS-CoV-2 RNA and viral proteins in liver non-parenchymal cells suggests that while the most extended primary viral cytotoxic effect occurs in the lung, viral components are present in other organs too, as in the liver. The necrosis/apoptosis and endothelial damage associated with viral infection in COVID-19 suggest that those patients who survive more severe COVID-19 may face prolonged liver repair and accordingly should be followed regularly in the post-COVID period.

SARS-CoV-2 infection drives an inflammatory response in human adipose tissue through infection of adipocytes and macrophages.

Obesity, characterized by chronic low-grade inflammation of the adipose tissue, is associated with adverse coronavirus disease 2019 (COVID-19) outcomes, yet the underlying mechanism is unknown. To explore whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of adipose tissue contributes to pathogenesis, we evaluated COVID-19 autopsy cases and deeply profiled the response of adipose tissue to SARS-CoV-2 infection in vitro. In COVID-19 autopsy cases, we identified SARS-CoV-2 RNA in adipocytes with an associated inflammatory infiltrate. We identified two distinct cellular targets of infection: adipocytes and a subset of inflammatory adipose tissue-resident macrophages. Mature adipocytes were permissive to SARS-CoV-2 infection; although macrophages were abortively infected, SARS-CoV-2 initiated inflammatory responses within both the infected macrophages and bystander preadipocytes. These data suggest that SARS-CoV-2 infection of adipose tissue could contribute to COVID-19 severity through replication of virus within adipocytes and through induction of local and systemic inflammation driven by infection of adipose tissue-resident macrophages.

Biobanking in times of crisis – The COVID-19 Autopsy and Biosample Registry Baden-Wuerttemberg

Biobanking plays a critical role in diagnostics, biomarker research and development of novel treatment approaches for various diseases. In urgent need of understanding, preventing and treating coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the importance of biobanking including data sharing and management further increased. To provide high quality tissue biomaterials and data for research and public health, the COVID-19 Autopsy and Biosample Registry was established in the state of Baden-Wuerttemberg (BW) in Germany, combining expertise and technologies of the Institutes of Pathology of the five university hospitals in BW (Heidelberg, Tübingen, Ulm, Freiburg, Mannheim). The COVID-19 Autopsy and Biosample Registry BW comprises tissue samples from autopsies and associated data of deceased patients in the context of SARS-CoV-2 infection and/or vaccination against SARS-CoV-2. The aim is to collect autopsy biospecimens, associated clinical and diagnostic data in a timely manner, register them, make them accessible for research projects and thus to support especially tissue-related research addressing COVID-19. By now, the BW network holds multiple collaborations and supported numerous publications to increase the understanding of COVID-19 disease. The achievements of the BW network as a landmark biobanking model project represent a potential blueprint for future disease-related biobanking and registry effort.

Human lungs show limited permissiveness for SARS-CoV-2 due to scarce ACE2 levels but virus-induced expansion of inflammatory macrophages.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) utilises the angiotensin-converting enzyme 2 (ACE2) transmembrane peptidase as cellular entry receptor. However, whether SARS-CoV-2 in the alveolar compartment is strictly ACE2-dependent and to what extent virus-induced tissue damage and/or direct immune activation determines early pathogenesis is still elusive. Spectral microscopy, single-cell/-nucleus RNA sequencing or ACE2 "gain-of-function" experiments were applied to infected human lung explants and adult stem cell derived human lung organoids to correlate ACE2 and related host factors with SARS-CoV-2 tropism, propagation, virulence and immune activation compared to SARS-CoV, influenza and Middle East respiratory syndrome coronavirus (MERS-CoV). Coronavirus disease 2019 (COVID-19) autopsy material was used to validate ex vivo results. We provide evidence that alveolar ACE2 expression must be considered scarce, thereby limiting SARS-CoV-2 propagation and virus-induced tissue damage in the human alveolus. Instead, ex vivo infected human lungs and COVID-19 autopsy samples showed that alveolar macrophages were frequently positive for SARS-CoV-2. Single-cell/-nucleus transcriptomics further revealed nonproductive virus uptake and a related inflammatory and anti-viral activation, especially in "inflammatory alveolar macrophages", comparable to those induced by SARS-CoV and MERS-CoV, but different from NL63 or influenza virus infection. Collectively, our findings indicate that severe lung injury in COVID-19 probably results from a macrophage-triggered immune activation rather than direct viral damage of the alveolar compartment.

COVID-19 Autopsies Reveal Underreporting of SARS-CoV-2 Infection and Scarcity of Co-infections.

Coronavirus disease 2019 (COVID-19) mortality can be estimated based on reliable mortality data. Variable testing procedures and heterogeneous disease course suggest that a substantial number of COVID-19 deaths is undetected. To address this question, we screened an unselected autopsy cohort for the presence of SARS-CoV-2 and a panel of common respiratory pathogens. Lung tissues from 62 consecutive autopsies, conducted during the first and second COVID-19 pandemic waves in Switzerland, were analyzed for bacterial, viral and fungal respiratory pathogens including SARS-CoV-2. SARS-CoV-2 was detected in 28 lungs of 62 deceased patients (45%), although only 18 patients (29%) were reported to have COVID-19 at the time of death. In 23 patients (37% of all), the clinical cause of death and/or autopsy findings together with the presence of SARS-CoV-2 suggested death due to COVID-19. Our autopsy results reveal a 16% higher SARS-CoV-2 infection rate and an 8% higher SARS-CoV-2 related mortality rate than reported by clinicians before death. The majority of SARS-CoV-2 infected patients (75%) did not suffer from respiratory co-infections, as long as they were treated with antibiotics. In the lungs of 5 patients (8% of all), SARS-CoV-2 was found, yet without typical clinical and/or autopsy findings. Our findings suggest that underreporting of COVID-19 contributes substantially to excess mortality. The small percentage of co-infections in SARS-CoV-2 positive patients who died with typical COVID-19 symptoms strongly suggests that the majority of SARS-CoV-2 infected patients died from and not with the virus.

Patterns of Inflammatory Cell Infiltration and Expression of STAT6 in the Lungs of Patients With COVID-19: An Autopsy Study.

Background:Severe acute respiratory syndrome coronavirus 2 causes diffuse alveolar damage (DAD), lymphocyte infiltration in the lungs and a cytokine storm. In this study we examined inflammatory cell infiltrates and the expression of signal transducer and activator of transcription (STAT) 6 in the lungs of patients with coronavirus disease 2019 (COVID-19).Methods:Eighteen COVID-19 autopsy cases, 9 non-COVID cases with DAD, and 11 controls without lung diseases were included. Immunostainings for STAT6, CD3, CD4, CD8, CD68, and broad-spectrum keratins were performed.Results:The average age of COVID-19 patients was 64.4±2.1 years. The disease duration was 7 to 53 days. The number of pneumocytes, macrophages or CD3+ T cells was significantly increased in the lungs of patients with COVID-19. Patients’ age above 67 years, blood troponin levels >0.2 ng/mL, platelet count >100×109/L, lung macrophages >130/high-power field (HPF), CD3+ T cells >145/HPF, CD8+ T cells <30/HPF, and CD8/CD4 ratio <1 were associated with shorter survival duration after onset of symptoms. In addition, STAT6 staining was much stronger in pneumocytes and lymphocytes in the lungs of patients with COVID-19 than non-COVID DAD patients or controls.Conclusion:Older age, high blood troponin level and platelet count, more macrophages and fewer CD8+ T cells in the lungs of COVID-19 were associated with poorer outcome. STAT6 expression was increased in pneumocytes and lymphocytes in the lungs of patients with COVID-19, implying a role of STAT6 in cytokine storms.

Aspirin use Reduces Platelet Hyperreactivity and Degranulation in COVID-19 Patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is spreading throughout the world at an alarming rate.[1] Severe disease is characterized by acute respiratory distress syndrome (ARDS), frequently associated with thrombotic complications.[2] [3] Some studies report the presence of platelets in thrombi found in multiple organs of COVID-19 autopsy cases.[4] [5] Moreover, hyperreactive platelets and overwhelming generation of inflammatory cytokines (i.e., a condition also known as “cytokine storm”) are frequent in COVID-19 patients.[6] [7] [8] [9] [10] [11] Furthermore, SARS-CoV-2 ribonucleic acid (RNA) could be detected in platelets of COVID-19 patients.[6] [10] [12] Despite these findings suggesting a role for platelets in the pathophysiology of COVID-19, the mechanisms of increased thrombotic events remain not completely elucidated.

Long-Term Persisting SARS-CoV-2 RNA and Pathological Findings: Lessons Learnt From a Series of 35 COVID-19 Autopsies.

BackgroundLong-term sequelae of coronavirus disease 2019 (COVID-19), including the interaction between persisting viral-RNA and specific tissue involvement, pose a challenging issue. In this study, we addressed the chronological correlation (after first clinical diagnosis and postmortem) between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and organ involvement.MethodsThe presence of postmortem SARS-CoV-2 RNA from 35 complete COVID-19 autopsies was correlated with the time interval between the first diagnosis of COVID-19 and death and with its relationship to morphologic findings.ResultsSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA can be evident up to 40 days after the first diagnosis and can persist to 94 hours after death. Postmortem SARS-CoV-2 RNA was mostly positive in lungs (70%) and trachea (69%), but all investigated organs were positive with variable frequency. Late-stage tissue damage was evident up to 65 days after initial diagnosis in several organs. Positivity for SARS-CoV-2 RNA in pulmonary swabs correlated with diffuse alveolar damage (p = 0.0009). No correlation between positive swabs and other morphologic findings was present. Cerebral (p = 0.0003) and systemic hemorrhages (p = 0.009), cardiac thrombi (p = 0.04), and ischemic events (p = 0.03) were more frequent in the first wave, whereas bacterial pneumonia (p = 0.03) was more prevalent in the second wave. No differences in biometric data, clinical comorbidities, and other autopsy findings were found.ConclusionsOur data provide evidence not only of long-term postmortem persisting SARS-CoV-2 RNA but also of tissue damage several weeks after the first diagnosis of SARS-CoV-2 infection. Additional conditions, such as concomitant bacterial pulmonary superinfection, lung aspergillosis, thromboembolic phenomena, and hemorrhages can further worsen tissue damage.

COVID-19 Autopsy in India: Protocols, Procedures, and Experiences.

Background: Coronavirus disease 2019 (COVID-19) has besieged mankind because of its novelty, causing a global health crisis. The autopsy-based studies provide a crucial role in understanding the pathophysiology and the behavior of the disease. But there is a paucity of such studies in the world especially so from developing nations. Conducting a complete autopsy on infectious bodies like COVID-19 requires conducive infrastructural setup and protocols suited to the needs, and precautions are to be taken meticulously.Methods: A complete pathological autopsy was conducted on a known case of a COVID-19-hospitalized patient, who died in our institution, with the aim to look for histopathological changes in each organ and to compare these findings with clinical findings such as duration of hospitalization, mechanical ventilation, comorbidities, biochemical parameters, and the result of real-time polymerase chain reaction (RT-PCR) of the tissues. The complete autopsy was performed after obtaining consent from the family, and the study was approved by the Institutional Ethics Committee. Histopathological examination (HPE) and RT-PCR were conducted on the tissue collected during autopsy. Clinical and biomedical data were collected and correlated.Result: The written informed consent from the family could be obtained in only 15.3% of cases, which was a limiting factor. The post-mortem interval ranged from 3.5 to 19.5 hours. The gross findings revealed pathologic features of viral infection as well as existing comorbidities in all the organs. The development of protocols and new innovations to limit the spread of infection, taking into consideration the limited facilities, which are described in this article, resulted in the successful completion of all the autopsies with a good sample collection, and nobody in the autopsy team was tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).Conclusions: The experience gained from these 21 COVID-19 autopsies helps to outline the basic or minimal requirements for conducting autopsies in highly infectious cases even in not-so-ideal conditions and also provides guidelines to be used while conducting such autopsies, especially in developing countries.

Computational pathology reveals unique spatial patterns of immune response in H&E images from COVID-19 autopsies: preliminary findings.

Purpose: We used computerized image analysis and machine learning approaches to characterize spatial arrangement features of the immune response from digitized autopsied H&E tissue images of the lung in coronavirus disease 2019 (COVID-19) patients. Additionally, we applied our approach to tease out potential morphometric differences from autopsies of patients who succumbed to COVID-19 versus H1N1. Approach: H&E lung whole slide images from autopsy specimens of nine COVID-19 and two H1N1 patients were computationally interrogated. 606 image patches ( per patient) of were extracted from the 11 autopsied patient studies. A watershed-based segmentation approach in conjunction with a machine learning classifier was employed to identify two types of nuclei families: lymphocytes and non-lymphocytes (i.e., other nucleated cells such as pneumocytes, macrophages, and neutrophils). Based off the proximity of the individual nuclei, clusters for each nuclei family were constructed. For each of the resulting clusters, a series of quantitative measurements relating to architecture and density of nuclei clusters were calculated. A receiver operating characteristics-based feature selection method, violin plots, and the t-distributed stochastic neighbor embedding algorithm were employed to study differences in immune patterns. Results: In COVID-19, the immune response consistently showed multiple small-size lymphocyte clusters, suggesting that lymphocyte response is rather modest, possibly due to lymphocytopenia. In H1N1, we found larger lymphocyte clusters that were proximal to large clusters of non-lymphocytes, a possible reflection of increased prevalence of macrophages and other immune cells. Conclusion: Our study shows the potential of computational pathology to uncover immune response features that may not be obvious by routine histopathology visual inspection.

Human kidney is a target for novel severe acute respiratory syndrome coronavirus 2 infection

It is unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can directly infect human kidney, thus leading to acute kidney injury (AKI). Here, we perform a retrospective analysis of clinical parameters from 85 patients with laboratory-confirmed coronavirus disease 2019 (COVID-19); moreover, kidney histopathology from six additional COVID-19 patients with post-mortem examinations was performed. We find that 27% (23/85) of patients exhibited AKI. The elderly patients and cases with comorbidities (hypertension and heart failure) are more prone to develop AKI. Haematoxylin & eosin staining shows that the kidneys from COVID-19 autopsies have moderate to severe tubular damage. In situ hybridization assays illustrate that viral RNA accumulates in tubules. Immunohistochemistry shows nucleocapsid and spike protein deposits in the tubules, and immunofluorescence double staining shows that both antigens are restricted to the angiotensin converting enzyme-II-positive tubules. SARS-CoV-2 infection triggers the expression of hypoxic damage-associated molecules, including DP2 and prostaglandin D synthase in infected tubules. Moreover, it enhances CD68+ macrophages infiltration into the tubulointerstitium, and complement C5b-9 deposition on tubules is also observed. These results suggest that SARS-CoV-2 directly infects human kidney to mediate tubular pathogenesis and AKI.

Tissue-based SARS-CoV-2 detection in fatal COVID-19 infections: Sustained direct viral-induced damage is not necessary to drive disease progression

Coronavirus disease 2019 (COVID-19) is an ongoing pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although viral infection is known to trigger inflammatory processes contributing to tissue injury and organ failure, it is unclear whether direct viral damage is needed to sustain cellular injury. An understanding of pathogenic mechanisms has been handicapped by the absence of optimized methods to visualize the presence and distribution of SARS-CoV-2 in damaged tissues. We first developed a positive control cell line (Vero E6) to validate SARS-CoV-2 detection assays. We then evaluated multiple organs (lungs, kidneys, heart, liver, brain, intestines, lymph nodes, and spleen) from fourteen COVID-19 autopsy cases using immunohistochemistry (IHC) for the spike and the nucleoprotein proteins, and RNA in situ hybridization (RNA ISH) for the spike protein mRNA. Tissue detection assays were compared with quantitative polymerase chain reaction (qPCR)-based detection. SARS-CoV-2 was histologically detected in the Vero E6 positive cell line control, 1 of 14 (7%) lungs, and none (0%) of the other 59 organs. There was perfect concordance between the IHC and RNA ISH results. qPCR confirmed high viral load in the SARS-CoV-2 ISH-positive lung tissue, and absent or low viral load in all ISH-negative tissues. In patients who die of COVID-19-related organ failure, SARS-CoV-2 is largely not detectable using tissue-based assays. Even in lungs showing widespread injury, SARS-CoV-2 viral RNA or proteins were detected in only a small minority of cases. This observation supports the concept that viral infection is primarily a trigger for multiple-organ pathogenic proinflammatory responses. Direct viral tissue damage is a transient phenomenon that is generally not sustained throughout disease progression.

An Immuno-Cardiac Model for Macrophage-Mediated Inflammation in COVID-19 Hearts.

[Figure: see text].

Postmortem Findings Associated With SARS-CoV-2: Systematic Review and Meta-analysis.

Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome-associated Coronavirus 2 (SARS-CoV-2), has become a global threat to public health. COVID-19 is more pathogenic and infectious than the prior 2002 pandemic caused by SARS-CoV-1. The pathogenesis of certain disease manifestations in COVID-19 such as diffuse alveolar damage (DAD) are thought to be similar to SARS-CoV-1. However, the exact pathogenesis of COVID-19 related deaths remains poorly understood. The aim of this article was to systematically summarize the rapidly emerging literature regarding COVID-19 autopsies. A meta-analysis was also conducted based on data accrued from preprint and published articles on COVID-19 (n=241 patients) and the results compared with postmortem findings associated with SARS-CoV-1 deaths (n=91 patients). Both autopsy groups included mostly adults of median age 70 years with COVID-19 and 50 years with SARS-CoV-1. Overall, prevalence of DAD was more common in SARS-CoV-1 (100.0%) than COVID-19 (80.9%) autopsies (P=0.001). Extrapulmonary findings among both groups were not statistically significant except for hepatic necrosis (P <0.001), splenic necrosis (P<0.006) and white pulp depletion (P <0.001) that were more common with SARS-CoV-1. Remarkable postmortem findings in association with COVID-19 apart from DAD include pulmonary hemorrhage, viral cytopathic effect within pneumocytes, thromboembolism, brain infarction, endotheliitis, acute renal tubular damage, white pulp depletion of the spleen, cardiac myocyte necrosis, megakaryocyte recruitment, and hemophagocytosis.

COVID-19 vasculitis and novel vasculitis mimics.

COVID-19 has been occasionally linked to histologically confirmed cutaneous vasculitis and a Kawasaki-like vasculitis, with these entities generally having minimal or no lung involvement and a good prognosis. Unlike these vasculitis types, patients with severe COVID-19 pneumonia can develop cutaneous vasculitis-like lesions and systemic arterial and venous thromboemboli, including cryptogenic strokes and other vasculopathy features. Proposed underlying mechanisms for these severe manifestations have encompassed immune dysregulation, including an anti-phospholipid syndrome-like state, complement activation, viral dissemination with direct systemic endothelial infection, viral RNAaemia with immunothrombosis, clotting pathway activation mediated by hypoxaemia, and immobility. In this Viewpoint, we highlight how imaging and post-mortem findings from patients with COVID-19 indicate a novel thrombosis in the pulmonary venous territory distal to the alveolar capillary bed, a territory that normally acts as a clot filtration system, which might represent an unappreciated nidus for systemic microembolism. Additionally, we suggest that this mechanism represents a novel vasculitis mimic related to COVID-19 that might lead to cryptogenic strokes across multivessel territories, acute kidney injury with haematuria, a skin vasculitis mimic, intestinal ischaemia, and other organ ischaemic manifestations. This finding is supported by pathological reports of extensive pulmonary venular thrombosis and peripheral organ thrombosis with pauci-immune cellular infiltrates. Therefore, severe COVID-19 pneumonia with extensive pulmonary intravascular coagulopathy might help to explain the numerous systemic complications of COVID-19, in which the demonstration of direct organ infection has not adequately explained the pathology.

Aspergillus Tracheobronchitis in COVID-19 ARDS Patients – A Cohort Study

Background: Coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome patients are at risk for fungal infections, especially aspergillosis and mucormycosis. COVID-19-associated pulmonary aspergillosis (CAPA) is differentiated in a pulmonary form and Aspergillus tracheobronchitis (ATB). During the first wave of the pandemic, bronchoscopy for diagnosing Aspergillus superinfections was rarely performed in COVID-19 patients, so that detailed on data on ATB in CAPA patients is scarce. We analyzed prevalence and mortality of tracheobronchitis in patients with CAPA.Methods: We conducted a retrospective, single-centre study at the 14-bed intensive care unit (ICU) of the Department I of Internal Medicine of the University Hospital of Cologne, Germany from March 2020 to February 2021. CAPA patients were identified by twice weekly analysis of tracheal aspirates for Aspergillus growth, Aspergillus DNA (PCR) and galactomannan combined with serum galactomannan testing. In case of positive results, bronchoscopy with the examination of trachea and lower airways and bronchoalveolar lavage followed.Findings: A total of 69 COVID-19 patients were admitted to the ICU, with 17 patients developing probable CAPA. All CAPA patients received bronchoscopy resulting in a clinical diagnosis of tracheobronchitis in 8 patients with signs of tracheal lesions, pseudomembranes or vulnerable bloody trachea. Seven bronchoalveolar lavages revealed culture and eight PCR positivity for Aspergillus fumigatus. In 7 of 8 tracheobronchitis patients, bronchoalveolar lavage samples tested positive for galactomannan antigen optical density index of >0.5. The overall mortality of CAPA patients was 52.9% and the overall mortality of ATB patients was 75%.Interpretation: Our data indicate a substantial prevalence of tracheobronchitis in this single-center cohort of CAPA patients. To facilitate early diagnosis bronchoscopic tracheal examination is crucial as computed tomography lacks diagnostic accuracy to enable timely initiation of therapy.Funding Information: This work was in part supported by the German Registry of COVID-19 Autopsies (www.DeRegCOVID.ukaachen.de), funded by the Federal Ministry of Health (ZMVI1-2520COR201), and the project DEFEAT PANDEMICs, funded by the Federal Ministry of Education and Research (01KX2021).Declaration of Interests: PK reports grants or contracts from German Federal Ministry of Research and Education and the State of North Rhine-Westphalia; Consulting fees Ambu GmbH, Gilead Sciences, Noxxon N.V. and Pfizer Pharma; Honoraria for lectures from Akademie für Infektionsmedizin e.V., Ambu GmbH, Astellas Pharma, BioRad Laboratories Inc., European Confederation of Medical Mycology, Gilead Sciences, GPR Academy Ruesselsheim, medupdate GmbH, MedMedia, MSD Sharp & Dohme GmbH, Pfizer Pharma GmbH, Scilink Comunicación Científica SC and University Hospital and LMU Munich; Participation on an Advisory Board from Ambu GmbH, Gilead Sciences, Pfizer Pharma; A pending patent currently reviewed at the German Patent and Trade Mark Office; Other non-financial interests from Elsevier, Wiley and Taylor & Francis online outside the submitted work. SvS none. JGB reports scientific grants and travel expenses from Kite/Gilead outside the submitted work. FF has a clinician scientist position supported by the deans office, medical faculty, University of Cologne. JSG none. FP none. BB reports honoraria, travel expenses and advisory role from/for Astellas, Celgene, Johnson & Johnson, Kite/Gilead, MSD, Novartis, Pfizer, Takeda and financing of scientific research by Astellas, Celgene, Kite/Gilead, MSD and Takeda outside the submitted work. DAE received honoraria from Sanofi and TAKEDA outside the submitted work. ASV reports travel grants from Gilead Sciences outside the submitted work. OK reports payment or honoraria for lectures, presentations or speakers bureaus by Gilead and Pfizer and receipt of equipment, materials, drugs, medical writing, gifts or other services by Pfizer, MSD, Basilea, Gilead, Virotech and Wako Fujifilm outside the submitted work. PB none. MK reports payment or honoraria for lectures, presentations or speakers bureaus by Gilead, MSD and Pfizer outside the submitted work. OAC reports grants or contracts from Amplyx, Basilea, BMBF, Cidara, DZIF, EU-DG RTD (101037867), F2G, Gilead, Matinas, MedPace, MSD, Mundipharma, Octapharma, Pfizer, Scynexis; Consulting fees from Amplyx, Biocon, Biosys, Cidara, Da Volterra, Gilead, Matinas, MedPace, Menarini, Molecular Partners, MSG-ERC, Noxxon, Octapharma, PSI, Scynexis, Seres; Honoraria for lectures from Abbott, Al 344 Jazeera Pharmaceuticals, Astellas, Grupo Biotoscana/United Medical/Knight, Hikma, MedScape, MedUpdate, Merck/MSD, Mylan, Pfizer; Payment for expert testimony from Cidara; Participation on a Data Safety Monitoring Board or Advisory Board from Actelion, Allecra, Cidara, Entasis, IQVIA, Jannsen, MedPace, Paratek, PSI, Shionogi; A pending patent currently reviewed at the German Patent and Trade Mark Office; Other interests from DGHO, DGI, ECMM, ISHAM, MSG-ERC, Wiley outside the submitted work.Ethics Approval Statement: Patients with CAPA were included in the FungiScope® global registry for emerging invasive fungal infections (https://www.clinicaltrials.gov; National Clinical Trials identifier NCT01731353), which was approved by the local ethics committee of the University of Cologne, Cologne, Germany (identifier 05-102).