A spark of hope: histopathological and functional recovery after critical COVID-19.

BACKGROUND: There are substantial concerns about fibrotic and vascular pulmonary sequelae after coronavirus disease 2019 (COVID-19) associated acute respiratory distress syndrome (ARDS).AQ1 Histopathology reports of lung biopsies from COVID-19 survivors are scarce. CASE: We herein report results of functional and histopathological studies in a 70 year-old man undergoing a co-incidental tumor lobectomy six months after long-term mechanical ventilation for COVID-19 pneumonia. CONCLUSION: Despite several unfavorable risk factors, this case presentation shows a completed pulmonary recovery process within a few months.

Neutrophil Extracellular Traps in Fatal COVID-19-Associated Lung Injury.

An excess formation of neutrophil extracellular traps (NETs), previously shown to be strongly associated with cytokine storm and acute respiratory distress syndrome (ARDS) with prevalent endothelial dysfunction and thrombosis, has been postulated to be a central factor influencing the pathophysiology and clinical presentation of severe COVID-19. A growing number of serological and morphological evidence has added to this assumption, also in regard to potential treatment options. In this study, we used immunohistochemistry and histochemistry to trace NETs and their molecular markers in autopsy lung tissue from seven COVID-19 patients. Quantification of key immunomorphological features enabled comparison with non-COVID-19 diffuse alveolar damage. Our results strengthen and extend recent findings, confirming that NETs are abundantly present in seriously damaged COVID-19 lung tissue, especially in association with microthrombi of the alveolar capillaries. In addition, we provide evidence that low-density neutrophils (LDNs), which are especially prone to NETosis, contribute substantially to COVID-19-associated lung damage in general and vascular blockages in particular.