Signatures of increased TGF-β activity in COVID-19 patients include increased plasma and serum TGF-β1 levels (77, 78), increased RNA levels of TGF β-induced protein in the blood of ARDS patients (79), plasmablast and monocyte TGF-β signatures in blood (80), increased IgA class switching pathognomonic of a TGF-β effect (81), and TGF-β mediated suppression of circulating NK cells (78). Here, TGFB1 is linked to COVID-19.