Actualités biologiques sur les angioedèmes à kinines

Kinin-mediated angioedema is characterized by episodic and recurrent pale and non-itching swelling involving subcutaneous or submucosal tissues (face and lips, hands or feet, gut, and occurrence in the upper airways), due to the increased vascular permeability. This phenomenon depends on vasoactive peptides, so-called kinins (bradykinin [BK], desArg9-BK, kallidine and substance P) produced from precursors, the kininogens, by the activity of serine proteases, the kininogenases (kallikrein, factor XII, plasmin). The pharmacological and physiopathological effects of kinins are mediated by the two types of receptors: B2 and B1. The angioedema disease is associated with an excessive and uncontrolled production of kinins and/or with a deficiency of the enzymes involved in the kinin catabolism (carboxypeptidase N, aminopeptidase P, angiotensin-I converting enzyme, dipeptidyl peptidase IV). The symptom expression is depending on precipitating factors. This disease could be inherited (HAE), acquired (AAE) or iatrogenic. Biological investigation of angioedema is based on several decisional parameters: the kinin production capacity (plasma kininogenase activity, cleavage of the natural substrates, amount of BK produced during an attack ; parameters investigated during the pathological period preferentially) ; efficient control of the kinin forming systems (C1 inhibitor) ; the enzymes of the kinin catabolism with the kininase assays. The genetic investigation strengthens the biological diagnostic with the knowledge of the familial molecular abnormality after examination of the susceptibility genes (SERPING1, F12 and XPNPEP2).