C1 esterase inhibitor (angioedema)

General Information

C1 esterase inhibitor is an inactivator of activated coagulation factor 12. It also inhibits plasmin, coagulation factor 11 and kallikrein. It is also an inhibitor of complement components – C1r and C1s.

On the other hand, C1-INH is an acute phase reactant protein, its production is stimulated by interleukin-6, interleukin-6, interferon-α and interferon-γ.

C1-INH deficiency increases the permeability of the blood vessel wall and causes angioedema (swelling around the blood vessel). This condition may be congenital or acquired.

Hereditary angioedema is an autosomal dominant disorder. There are 2 forms of the disease: in variant I, the synthesis of C1 inhibitor is reduced, and in variant II, an abnormal form of C1 inhibitor is synthesized, due to which its activity decreases.

From a clinical point of view, there is no difference between these two forms. The disease begins in childhood or adolescence - with subcutaneous and/or submucous edema. The swollen area is painless, non-swelling, non-compressible (that is, it does not disappear under pressure). Episodes are self-limiting - that is, the swelling will go away by itself in 2-5 days. The frequency, severity, and intensity of its development are variable. The causes have not been fully studied.

The usual location of edema development is: face, limbs, genitals, respiratory and gastrointestinal tract. Vomiting and diarrhea are symptomatic when localized in the intestines. When the center of swelling is located in the respiratory tract, a life-threatening obstruction (suffocation of the respiratory tract) may develop. Treatment of angioedema involves long-term administration of mild androgens, which increase serum C1-INH concentrations in both forms of the disease.

An acquired form of angioedema has been described, especially in elderly patients with lymphoproliferative, autoimmune, neoplastic diseases.