Identification of Histopathological Biomarkers in Fatal Cases of Coronavirus Disease: A Study on Lung Tissue

Abstract

We aimed to evaluate the primary lung postmortem macro- and microscopic biomarkers and factors associated with diffuse alveolar damage in patients with fatal coronavirus (COVID-19). We retrospectively analyzed lung tissue collected from autopsies performed in Cluj-Napoca, Romania, between April 2020 and April 2021 on patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We examined 79 patients with confirmed SARS-CoV-2 infection, ages 34 to 96 years, split into two groups using the cut-off value of 70 years. Arterial hypertension (38%) and type 2 diabetes mellitus (19%) were the most common comorbidities with similar distribution between groups (p-values > 0.14). Macroscopically, bloody exudate was more frequently observed among patients < 70 years (33/36 vs. 29/43, p-value = 0.0091). Diffuse alveolar damage (53.1%) was similarly observed among the evaluated groups (p-value = 0.1354). Histopathological biomarkers of alveolar edema in 83.5% of patients, interstitial pneumonia in 74.7%, and microthrombi in 39.2% of cases were most frequently observed. Half of the evaluated lungs had an Ashcroft score of up to 2 and an alveolar air capacity of up to 12.5%. Bronchopneumonia (11/43 vs. 3/36, p-value = 0.0456) and interstitial edema (9/43 vs. 2/36, p-value = 0.0493) were significantly more frequent in older patients. Age (median: 67.5 vs. 77 years, p-value = 0.023) and infection with the beta variant of the virus (p-value = 0.0071) proved to be significant factors associated with diffuse alveolar damage.

Immunohistochemical and Morphometric Analysis of Lung Tissue in Fatal COVID-19

“…No statistically significant differences in comorbidities, age, or sex were associated with the presence or absence of DAD. Furthermore, we noted that most patients with DAD had interstitial pneumonia (72.5%), which was previously reported on hematoxylin and eosin staining [28].…”

Flurona: The First Autopsied Case

“…Being rich in B lymphocytes ( Figure 3 K), we consider that bronchitis/bronchiolitis is likely due to the influenza virus. Additionally, in our previous studies, we observed that COVID-19 infection generally does not produce intense histological inflammation in the bronchial structures [ 23 , 24 ]. The involvement of bronchial structures has been reported in infections with influenza, adenovirus, herpes, varicella-zoster, and respiratory syncytial virus [ 25 ].…”