Lymphoproliferative disease and acquired C1 inhibitor deficiency.

Angioedema due to acquired deficiency of the C1-inhibitor is a bridging condition between autoimmunity and lymphoproliferation. We report 32 patients with acquired C1 inhibitor deficiency: 23 have anti C1-inhibitor autoantibodies; 13 have monoclonal gammopathies of unknown significance and 9 have non-Hodgkin's lymphoma. Our series suggest that different forms of B cell disorders coexist and/or evolve into each other in acquired angioedema.