Item

Abstract

IMPORTANCE Myocardial injury is a common feature of patients with SARS-CoV-2 infection. However, the cardiac inflammatory processes associated with SARS-CoV-2 infection are not completely understood.
OBJECTIVE To investigate the inflammatory cardiac phenotype associated with SARS-CoV-2 infection compared with viralmyocarditis, immune-mediatedmyocarditis, and noninflammatory cardiomyopathy by integrating histologic, transcriptomic, and proteomic profiling.
DESIGN, SETTING, AND PARTICIPANTS This case serieswas a cooperative study between the Ludwig Maximilian University Hospital Munich and the Cardiopathology Referral Center at the University of Tubingen in Germany. A cohort of 19 patients with suspectedmyocarditis was examined; of those, 5 patients were hospitalized with SARS-CoV-2 infection between March and May 2020. Cardiac tissue specimens from those 5 patients were compared with specimens from 5 patients with immune-mediatedmyocarditis, 4 patients with non-SARS-CoV-2 viralmyocarditis, and 5 patients with noninflammatory cardiomyopathy, collected from January to August 2019.
EXPOSURES Endomyocardial biopsy.
MAIN OUTCOMES AND MEASURES The inflammatory cardiac phenotypeswere measured by immunohistologic analysis, RNA exome capture sequencing, and mass spectrometry-based proteomic analysis of endomyocardial biopsy specimens.
RESULTS Among 19 participants, the median age was 58 years (range, 37-76 years), and 15 individuals (79%) were male. Data on race and ethnicity were not collected. The abundance of CD163+ macrophages was generally higher in the cardiac tissue of patients with myocarditis, whereas lymphocyte counts were lower in the tissue of patients with SARS-CoV-2 infection vs patients with non-SARS-CoV-2 virus-associated and immune-mediatedmyocarditis. Among those with SARS-CoV-2 infection, components of the complement cascade, including C1q subunits (transcriptomic analysis: 2.5-fold to 3.6-fold increase; proteomic analysis: 2.0-fold to 3.4-fold increase) and serine/cysteine proteinase inhibitor clade G member 1 (transcriptomic analysis: 1.7-fold increase; proteomic analysis: 2.6-fold increase), belonged to the most commonly upregulated transcripts and differentially abundant proteins. In cardiac macrophages, the abundance of C1q was highest in SARS-CoV-2 infection. Assessment of important signaling cascades identified an upregulation of the serine/threonine mitogen-activated protein kinase pathways.
CONCLUSIONS AND RELEVANCE This case series found that the cardiac immune signature varied in inflammatory conditions with different etiologic characteristics. Future studies are needed to examine the role of these immune pathways inmyocardial inflammation.