Table 2.

Clinical evidence of complement deposition in multi-organs from COVID-19 patients

Organ	Collective evidence of complement activation	References
Lung	Strong expression of MBL, MSAP2, C4a, C3, and MAC C5b-9 in paraformaldehyde-fixed lung tissue from patients who died of COVID-19 N proteins from SARS-CoV-2 could bind MBL and activate MASP-2	Gao et al. [23]
	Striking deposition of C5b-9, C4d, and MASP2 in the microvasculature were found in the lung A co-localization of COVID-19 spike glycoprotein with C4d and C5b-9 were also found in the inter-alveolar septa	Magro et al. [24]
	Transcriptome data from lung tissue of two patients with SARS-CoV-2 infection, and in vitro respiratory epithelial cells showed the complement pathway was one of the most significant induced pathways	Yan et al. [26]
Kidney	C5b-9 deposition on tubules in all six cases along with low expression of C5b-9 on glomeruli and capillaries in kidney from COVID-19 patients	Diao et al. [30]
Skin	Three patients with critical COVID-19 had purpuric skin rash with striking deposition of C5b-9 and C4d in both grossly involved and normally appearing skin, and colocalization of SARS-CoV-2-specific spike glycoprotein	Magro et al. [24]
	Two children with Kawasaki-like hyperinflammatory syndrome were reported as a novel SARS-CoV-2 induced phenotype in Italy, with obvious complement consumption	Licciardi et al. [31]