Molecule

C3

Central complement component

Expression change
Depleted (consumed)
Evidence level
established

Role in pathogenesis

C3 is consumed during classical pathway activation. Its cleavage generates C3a (anaphylatoxin causing mast cell degranulation) and C3b (opsonin). C3 deposition in vessel walls is the most frequent direct immunofluorescence finding on skin biopsy.

Sources (3)

DetailsDavis MD et al. (1998) Clinicopathologic correlation of hypocomplementemic and normocomplementemic urticarial vasculitisPubMed ↗
DetailsMarzano AV et al. (2022) Urticarial vasculitis: Clinical and laboratory findings with a particular emphasis on differential diagnosisDOI ↗
DetailsLopez LR et al. (1984) The hypocomplementemic urticarial-vasculitis syndrome: therapeutic response to hydroxychloroquineDOI ↗