The median MASP-1/C1-INH complex levels observed in COVID-19 cases were 38% increased (median levels in cases vs. controls: 39.7 vs. 54.5 ng/mL), and C4d levels were 67% elevated when compared to HCs (median levels in cases vs. controls: 2.26 vs. 3.78 ng/mL). This evidence concerns the gene SERPING1 and COVID-19.