MBTPS1 and COVID-19: These data lead to the hypothesis that lower signaling tone from S1P receptors results in increasing susceptibility of interferon‐α auto‐amplification from plasmacytoid dendritic cells and poorer maintenance of endothelial integrity, as well as providing an environment in which small increases in S1P produced by inflammatory processes could result in lymphocyte sequestration and the lymphopenia seen during the COVID‐19 crisis.