An Autopsy Study of Lung During Covid -19 Pandemic Period - Correlation of Histopathologic findings with Covid -19 IHC Marker
Background: SARS-CoV-2 infection, declared a pandemic by WHO, predominantly affects the lungs and causes significant morbidity and mortality. Although autopsy studies worldwide have described the lung pathology of COVID-19, there is limited data from South India. Objectivesl:• To describe the histopathological features in lung tissues of patients who died with pulmonary pathology during the COVID-19 pandemic. • To assess the expression of SARS-CoV-2 immunohistochemistry (IHC) marker and correlate findings with histopathological patterns. Methods: A descriptive cross-sectional study was conducted in the Department of Pathology, Government Medical College, Manjeri, on 70 autopsy lung specimens (March 2020–April 2021). H&E-stained slides were examined for diffuse alveolar damage (DAD), vascular, interstitial, and mixed injury patterns. IHC using monoclonal antibody to SARS-CoV-2 spike protein was performed. Results: The study included 44 males (62.9%) and 26 females (37.1%), mean age 45 years. DAD was the predominant finding (40%), with 23 cases in the acute phase and 5 in the organizing phase. Vascular changes, mainly microthrombi, were seen in 17 cases (24.3%). Mixed patterns were noted in 21 cases (30%), including bronchopneumonia and lobar pneumonia. IHC positivity was observed in 25 cases (35.7%), with staining in alveola macrophages, interstitial macrophages, and type II pneumocytes, but not in endothelial cells. Conclusion: DAD is the central histopathological feature in COVID-19 lung injury, often associated with vascular damage and secondary infections. IHC findings confirm viral involvement of macrophages and pneumocytes, with selective cell tropism.