MASP2 and COVID-19: A series of cutaneous biopsy and pulmonary autopsy samples from 5 patients with severe COVID-19 revealed a pattern of TMA and severe activation of the complement cascade as evidenced by vascular deposits of C5b-9 (membrane attack complex), mannose-binding protein-associated serine protease 2 (MASP2) and C4b, demonstrating severe activation of the complement cascade [117].