IL6 and COVID-19: The soluble IL-6 receptor (sIL6R), a negative regulator of IL-6 signaling, has been suggested to affect many complex traits and diseases including lipid levels (e.g., high-density lipoprotein cholesterol, HDL-c), both severity and susceptibility of COVID-19, heart diseases (e.g., atrial fibrillation, AF), autoimmune diseases (e.g., Crohn’s disease, CD), and others25,26.