Imaging of COVID-19 simulators

Comprehensive Analysis of Disease Pathology in Immunocompetent and Immunocompromised Hosts following Pulmonary SARS-CoV-2 Infection

The Coronavirus disease 2019 (COVID-19) pandemic disproportionately affects immunocompetent and immunocompromised individuals, with the latter group being more vulnerable to severe disease and death. However, the differential pathogenesis of SARS-CoV-2 in the context of a specific immunological niche remains unknown. Similarly, systematic analysis of disease pathology in various extrapulmonary organs in immunocompetent and immunocompromised hosts during SARS-CoV-2 infection is not fully understood. We used a hamster model of SARS-CoV-2 infection, which recapitulates the pathophysiology of patients with mild-to-moderate COVID-19, to determine the dynamics of SARS-CoV-2 replication and histopathology at organ-level niches and map how COVID-19 symptoms vary in different immune contexts. Hamsters were intranasally infected with low (LD) or high (HD) inoculums of SARS-CoV-2, and the kinetics of disease pathology and viral load in multiple organs, antibody response, inflammatory cytokine expression, and genome-wide lung transcriptome by RNAseq analysis were determined and compared against corresponding responses from chemically induced immunocompromised hamsters. We observed transient body weight loss proportional to the SARS-CoV-2 infectious dose in immunocompetent hamsters. The kinetics of viral replication and peak viral loads were similar between LD and HD groups, although the latter developed more severe disease pathology in organs. Both groups generated a robust serum antibody response. In contrast, infected immunocompromised animals showed more prolonged body weight loss and mounted an inadequate SARS-CoV-2-neutralizing antibody response. The live virus was detected in the pulmonary and extrapulmonary organs for extended periods. These hamsters also had persistent inflammation with severe bronchiolar-alveolar hyperplasia/metaplasia. Consistent with the differential disease presentation, distinct changes in inflammation and immune cell response pathways and network gene expression were seen in the lungs of SARS-CoV-2-infected immunocompetent and immunocompromised animals.

COVID-19 and eosinophilic granulomatosis with polyangiitis or COVID-19 mimicking eosinophilic granulomatosis with polyangiitis?

Coronavirus disease 2019 (COVID-19) and eosinophilic granulomatosis with polyangiitis (EGPA) share similarities in clinical, imaging findings and may present with respiratory distress. Differentiating a new-onset EGPA from COVID-19 during the current pandemic is a diagnostic challenge, particularly if other EGPA symptoms are overlooked. Here in this study we reviewed the literature regarding EGPA patients with COVID-19 and patients who diagnosed with EGPA or suffered an EGPA flare mimicking COVID-19. We conducted a literature survey in PUBMED database using meshed keywords “COVID-19” and “EGPA”, “COVID-19” and “eosinophilic granulomatosis with polyangiitis”, “COVID-19” and “Churg Strauss Syndrome”, to reveal previously reported cases involving EGPA patients who had COVID-19 infection, patients who suspected to have COVID-19 but eventually diagnosed with EGPA and patients with a known diagnosis of EGPA who suffered a flare but a COVID-19 infection was suspected initially. A total of 11 cases (6 literature cases, 5 cases from our clinic) were included in our study. Seven (63.6%) of the cases were defined as COVID-19 mimicker and 4 (36.4%) were EGPA with COVID-19. All of the cases in EGPA with COVID-19 group had a history of asthma. All of them had a positive PCR result and ground-glass opacities in thorax CT. In COVID-19 mimicker group, six (85.7%) patients had a history of asthma and other EGPA features that were observed were eosinophilia in 6 (85.7%). Our study provided clues regarding the EGPA/COVID-19 diagnostic challenge which may be useful in the current pandemic. Since none of the findings in COVID-19 are disease-specific, other conditions like EGPA should not be overlooked particularly in PCR negative patients and clinical, laboratory and imaging findings should be interpreted carefully. Furthermore, we did not observe poor outcomes in EGPA patients who had COVID-19.