Covid-19 cytokine storm in pulmonary tissue: Anatomopathological and immunohistochemical findings
Anna Flavia Ribeiro dos Santos Miggiolaro, Jarbas da Silva Motta, Caroline Busatta Vaz de Paula, Seigo Nagashima, Mineia Alessandra Scaranello Malaquias, Lucas Baena Carstens, Andréa Novais Moreno-Amaral, Cristina Pellegrino Baena, Lúcia de Noronha
Abstract
The COVID-19 pandemic is a worldwide threat, and information on physiopathological aspects of the disease is limited. Despite efforts in searching treatment options, a better understanding of the SARS-CoV-2 pathways can contribute to managing severe cases. In this study, we aim to describe pathological and immunopathogenic findings of two different cases, both in the high-risk group. Post-mortem lung biopsies were analyzed by traditional and immunohistochemical methods. Tissue expression of innate and adaptive immune response biomarkers was tested. We observed a higher innate response in case 1 with an abundance of mast cells, scarce CD8+ lymphocytes, high expression of TNF-alpha, and almost absent adaptative immune response. In case 2, the adaptative immune response was present, with numerous CD8+ lymphocytes and higher levels of IL-4 and TGF-beta. Both cases converged to a prothrombotic state expressing high IL-6, followed by ICAM-1 expression and endotheliites leading to systemic inflammatory response syndrome. In conclusion, differences in age and comorbidities and immune response described here may be related to the SARS-CoV-2 delay in the adaptative immune response, evolution stage of diffuse alveolar damage, and progression for systemic inflammatory response syndrome.