C1-INHIBITOR BINDING MONOCLONAL IMMUNOGLOBULINS IN 3 PATIENTS WITH ACQUIRED ANGIONEUROTIC-EDEMA

The syndrome of acquired angioneurotic edema (AAE) is characterized by the adult onset of angioedema, the lack of evidence for inheritance o f the disorder, and the frequent association of the C1-inhibitor (C1-I NH) deficiency with lymphoproliferative or other malignant diseases. R ecently, a new type of AAE (type II AAE) has been described. The two m ajor biologic differences of this new syndrome compared with all other previously reported AAE cases (type I AAE) are the presence in patien ts' sera of both anti-C1-INH autoantibodies, often monoclonal, and a c irculating low molecular weight (95 kd) Ci-INH protein. From the clini cal point of view, the absence of underlying lymphoproliferative disea se is the hallmark of type II AAE compared with type I AAE. However, t he distinction between type I and type II AAE may not be so clear-cut. We report three patients with monoclonal gammopathies and AAE for who m the initial diagnosis was type I AAE. The demonstration by ELISA of the C1-INH binding ability of their monoclonal immunoglobulins in addi tion to the presence of 95 kd C1-INH protein enables us to change the diagnosis to type II AAE. From the therapeutic point of view, it is cr ucial to detect the anti-C1-INH antibody and to analyze the C1-INH siz e to distinguish type I and type II AAE, especially if patients have a monoclonal gammopathy, to give the appropriate treatment (attenuated androgens vs immunosuppressive regimen, respectively) to prevent a fat al outcome.