What causes acquired angioedema (AAE) due to C1 inhibitor (C1-INH) deficiency (C1-INH-AAE) type II?

Updated: May 20, 2020
  • Author: Amanda T Moon, MD; Chief Editor: William D James, MD  more...
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Acquired angioedema type II is not associated with any specific disorder but rather is characterized by the presence of autoantibody directed against C1-INH. Most of these antibodies work by binding the epitopes around the reactive center of INH. [6] However, the occasional existence of features of both acquired angioedema type I and acquired angioedema type-II has been noted, most notably with a MGUS.

A 2016 study reported that 33% of patients presenting with acquired angioedema had or would develop non-Hodgkin lymphoma, in particular marginal zone lymphoma. Of the studied patients, 62.5% were diagnosed with non-Hodgkin lymphoma at the onset of angioedema or up to 7 years later. Patients presenting with acquired angioedema and C1-INH deficiency should be monitored regularly for the development of malignancy. [7]

In addition to associations with MGUS, C1-INH–deficient AAE has also been reported in monoclonal gammopathy of renal significance (MGRS). [8] One case of acquired angioedema with C1-INH deficiency state was identified in association with liver transplantation. The status of the liver donor was unknown, but it is speculated that the donor may have been C1-INH deficient. Another case of acquired angioedema was reported with acute upper airway angioedema in association with the local anesthetic articaine.

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