T cell receptor excision circles (TREC) and Kappa-deleting recombination excision circles (KREC) counts in patients with acute COVID-19 and COVID-19 convalescent patients. Scatters plots (A,B) showing the numbers (copies per 105 cells) of TRECs and KRECs, respectively Black circles—healthy control (HC, n = 24); black triangles—patients with acute COVID-19 (COV (fav), favorable outcome, n = 25); black squares—patients with acute COVID-19 (COV (unf), unfavorable outcome, n = 8); and white circles—COVID-19 survivors (CON, convalescent patients with favorable outcome of acute COVID-19, n = 33). Each dot represents individual subjects, and horizontal bars depict the group medians and quartile ranges (Med (Q25; Q75). Statistical analysis was performed with the Mann–Whitney U test.