SERPINE1 and COVID-19: The relatively higher plasma PAI-1 Ag level [131.1 ng/mL (128.7–131.9)] identified in the severe COVID-19 participants corresponds with earlier findings from the study by Nougier et al. where PAI-1 levels among COVID-19 patients in ICU was 96.3 ± 35 ng/mL, compared to the non-severe group, 76.8 ± 40 ng/mL [14].