Bradykinin-degradating Enzymes Activities in Angiotensin-Converting Enzyme Inhibitors-associated Angioedema

Angiotensin-Converting-Enzyme-inhibitors-dependent angioedema (ACEi-AE) is the most frequent form of bradykinin-mediated AE, with an estimated prevalence of 0.1% to 0.7%. These AE can be explained by the accumulation of bradykinin (BK), a peptide responsible for increase of vascular permeability: ACE inhibitors block ACE, the main inactivation pathway of the BK, thus extending its half-life. In spite of the the stopping of the drug, systematically performed in the case of ACEi-AE, up to 50% of patients relapsed within 6 months, with maximum risk in the first month after stopping. In addition, the discontinuation of these drugs represents a loss of chance for some patients, without clearly established mastocytic (or histaminic) or bradykinic etiology. At present there is no method to predict the risk of crisis recurrence in patients who have developed AE-IEC. The investigators hypothesize that the risk of relapse is associated with a decrease in the activity of BK degradation enzymes (including aminopeptidase P (APP), dipeptidyl peptidase-4 (DPP4), and ECA) that persists at the cessation of IEC.