Complement C1 inhibitor protein (C1-INH)

Complement C1 inhibitor protein (C1-INH) is a highly glycosylated plasma protein and member of the serpin (serine protease inhibitor) superfamily. It is the primary regulator of the classical complement pathway, preventing inappropriate activation by inhibiting the proteases C1r and C1s. C1-INH also plays a crucial role in modulating the contact system by inhibiting plasma kallikrein, factor XIIa, and factor XIa, which are responsible for the generation of bradykinin. Deficiency or dysfunction of C1-INH results in hereditary or acquired angioedema, manifested as episodic swelling that can be life-threatening. The SERPING1 gene, located on chromosome 11, encodes C1-INH. Therapeutic targeting of C1-INH is well established, including intravenous, subcutaneous, or recombinant replacement in patients with deficiency disorders, and it serves as a model for serpinopathies due to the conformational sensitivity of the protein to mutations and the resultant disease phenotypes

Other names

C1 esterase inhibitorC1INHSERPING1 (gene name)Complement component 1 inhibitor

Direct replacement therapy: exogenous C1-inhibitor inhibits target proteases in complement and contact systems, reducing bradykinin formation and controlling inflammatory processes; Upregulation of endogenous expression: certain drugs, like androgens, increase production of C1-INH protein