Serum levels of ficolin-2 (p < 0.001), MASP-3 (p = 0.030), and MAp44 (p < 0.001) were significantly elevated, while antigenic MBL (p < 0.001) and MASP-1 (p < 0.001) were significantly reduced in SLE patients compared to healthy controls (HCs). This evidence concerns the gene FCN2 and systemic lupus erythematosus.