Similarly, in previous reports, FGB, FGG, complements C4, C3, C5, C2, C9 [13], and complement C1q subcomponent subunits A, B, and C (C1QA, C1QB and C1QC) [16] were found to be upregulated in the lung tissues of patient with COVID-19. The gene discussed is C2; the disease is COVID-19.