C1-inhibitor

C1-inhibitor is a type of medicine that helps to prevent or reduce inflammation in the body. It works by blocking the activity of C1, an enzyme involved in the body's inflammatory response. C1-inhibitor is usually prescribed for people with autoimmune diseases or chronic inflammatory conditions. It is available in oral, intramuscular, or intravenous forms and is often used in combination with other medications to control inflammation and reduce symptoms.

C1-inhibitor, also known as C1 esterase inhibitor (C1-INH), is a protein found in the blood plasma. It plays a crucial role in regulating several critical systems within the body, including:

• Complement system: This intricate network of proteins defends the body against infections and helps clear debris from the body. C1-inhibitor acts as a major regulator of this system, preventing its uncontrolled activation, which can lead to tissue damage. Specifically, it inactivates specific proteins (C1r and C1s) within the complement system, preventing the cascade of events that can trigger inflammation and tissue injury.
• Contact system: This system is involved in blood clotting and inflammatory responses. C1-inhibitor also functions as an inhibitor within this system, regulating the activity of proteins like factor XIIa and kallikrein, thereby preventing excessive clotting and inflammation.
• Fibrinolytic system: This system is responsible for breaking down blood clots. C1-inhibitor plays a role in modulating this system, ensuring proper clot breakdown and preventing excessive bleeding.

Here are some additional key points about C1-inhibitor:

• Classification: It belongs to the serpin family of proteins, known for their inhibitory properties.
• Normal levels: C1-inhibitor circulates in the blood at around 0.25 grams per liter (g/L). These levels can increase during inflammation.
• Deficiency: A deficiency of C1-inhibitor can lead to a condition called hereditary angioedema (HAE), characterized by episodes of sudden swelling in various tissues, particularly the face, lips, and airway. This can be life-threatening if it affects the airway.