FOXP3 and COVID-19: This overexpression had a consequence: Tregs from severe COVID-19 patients displayed a heightened expression of Treg signature transcripts (Fig. 2A), reflected by a high TregSignature index, most markedly biased in the severe group, but also in mild and recovered patients (Fig. 2B), and correlating with FOXP3 expression (SI Appendix, Fig. S2C).