Evidence of Autoinflammation as a Principal Mechanism of Myocardial Injury in SARS-CoV-2 PCR-Positive Medical Examiner Cases

Background Disease from Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) remains the third leading cause of death in the United States, after cancer and heart disease. Many patients infected with this virus develop later cardiovascular complications including myocardial infarctions, stroke, arrhythmia, heart failure, and sudden cardiac death (20–28%). The purpose of this study is to understand the primary mechanism of myocardial injury in patients infected with SARS-CoV-2. Methods We investigated a consecutive cohort of 48 medical examiner cases who died with PCR-positive SARS-CoV-2 (COVpos) infection in 2020. We compared them to a consecutive cohort of 46 age and sex-matched controls who were PCR-negative for SARS-CoV-2 (COVneg). Clinical information available at postmortem examination was reviewed on each patient. Formalin-fixed sections were examined using antibodies directed against CD42 (platelets), CD15 (myeloid cells), CD68 (monocytes), C4d, Fibrin, CD34 (stem cell antigen), CD56 (natural killer cells), and Myeloperoxidase (MPO) (neutrophils and NETs). We used a Welch 2-sample T-test to determine significance. A cluster analysis of marker distribution was also done. Results We found a significant difference between COVpos and COVneg samples for all markers, all of which were significant at p < 0.001. The most prominent features were neutrophils (CD15, MPO) and MPO positive debris suggestive of NETS. A similar distribution of platelets, monocytes, fibrin and C4d was seen in COVpos cases. Clinical features were similar in COVpos and COVneg cases for age, sex, and body mass index (BMI). Conclusion These findings suggest an autoinflammatory process is likely involved in cardiac damage during these infections.