Identification of novel biomarkers to distinguish bradykinin-mediated angioedema from mast cell-/histamine-mediated angioedema

Background The pathophysiology of the underlying paroxysmal permeability disturbances in angioedema (AE) is not well understood. Methods To identify clinical and laboratory parameters specific for a certain AE subtype, 40 AE patients were prospectively enrolled: 15 hereditary (HAE), 13 ACE-inhibitor induced (ACE-AE), and 12 mast cell-mediated without wheals in chronic spontaneous urticaria (CSU-AE). Ten healthy subjects served as controls. Serum levels of markers indicating activation of the ficolin-lectin pathway, of endothelial cells, or those indicating impairment of vascular integrity or inflammation were assessed by enzyme-linked immunosorbent assay. Results New routine clinical diagnostic criteria could not be identified, not even for distinguishing bradykinin-mediated (BK-) AE (ie, HAE and ACE-AE) from mast cell-/histamine-mediated CSU-AE. However, FAP-alpha and tPA were significantly increased in all AE compared to controls. In HAE, FAP- alpha, tPA, uPAR, pentraxin-3, Tie-2, sE-selectin, and VE-cadherin were significantly increased compared to controls. In HAE compared to CSU-AE and ACE-AE, sE-Selectin, Tie-2, and VE-Cadherin were significantly increased, whereas for Ang-2 the difference was significant compared to CSU-AE only. Tie-2 correlated strongly negatively with C4, C1-INH activity, and C1-INH function. Conclusions This study is the first to compare HAE, ACE-AE, and CSU-AE. Although significance is limited by small sample size, Tie-2 was identified as a new promising biomarker candidate for HAE. FAP- alpha and tPA might serve as a marker for AE in general, whereas sE-selectin and Ang-2 were increased in BK-AE only. Our results add information to the role of endothelial dysfunction and serine proteases in different AE subtypes.