Luminex assays on patient sera demonstrated that as previously shown COVID-19 positive patients had significantly greater levels of IL-6, TNF-α, IL-1β, IL-10, and CRP (Figure 1F–K).18 Taken collectively, COVID-19 patient serum (which contains multiple proinflammatory cytokines) results in cardiomyocyte toxicity in our in vitro assay. Here, TNF is linked to COVID-19.