Hereditary Angioedema (HAE)
Hereditary angioedema (HAE) is a rare inherited disorder featuring recurring episodes of fluid accumulation in tissues which blocks the normal flow of blood or lymphatic fluid causing rapid swelling of tissues in the hands, feet, limbs, face, intestinal tract, or airway. Usually, this swelling is not accompanied by itching, as it ordinarily is with an allergic reaction. Swelling of the airway may lead to obstruction, a potentially dangerous complication. Swelling of the gastrointestinal tract leads to cramping. These symptoms develop as the result of deficiency or improper functioning of certain proteins that help to maintain the normal flow of fluids through very the smallest blood vessels (capillaries). In some cases, fluid may accumulate in other internal organs. The severity of the disease varies among affected individuals. The most common form of the disorder is hereditary angioedema type I (HAE 1), which is the result of abnormally low levels of certain complex proteins in the blood (C1 esterase inhibitors), known as complements. They help to regulate various body functions (e.g., flow of body fluids in and out of cells). Hereditary angioedema type II (HAE 2) is a more uncommon form of the disorder and occurs as the result of the production of abnormal complement proteins.
Effective treatment has been available in Europe for 30 years. Now Lev Pharmaceuticals of New York has brought this treatment to the U.S. It involves twice weekly infusion of the missing complex proteins and while this sounds inconvenient, it is much less inconvenient that suffering from frequent bouts of HAE. The complement is named C1-INH. Confirmation of the European experience as published in the New England Journal of Medicine in 1996, providing evidence that this treatment is safe and effective for both prevention of attacks and as an acute attack therapy – rapid resolution of laryngeal, facial, abdominal and extremity swelling was observed. A study published in the Archives of Internal Medicine in 2001 concluded C1-INH to be highly effective in treating the laryngeal edema of HAE with rapid resolution of symptoms.