Acquired C1 Esterase Inhibitor Deficiency

Markovic, Svetomir N. MD, PhD
Inwards, David J. MD
Frigas, Evangelos A. MD
Phyliky, Robert P. MD

From Mayo Clinic, Rochester, Minnesota.

For author affiliations and current addresses, see end of text.

Grant Support: From the Mayo Foundation.

Requests for Reprints: Svetomir N. Markovic, MD, PhD, Division of Hematology, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester MN, 55901. For reprint orders in quantities exceeding 100, please contact Barbara Hudson, Reprints Coordinator; phone, 215-351-2657; e-mail, [email protected].

Current Author Addresses: Drs. Markovic, Inwards, and Phyliky: Division of Hematology, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901.

Dr. Frigas: Division of Allergy and Outpatient Infectious Diseases, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55901.

Annals of Internal Medicine 132(2):p 144-150, January 18, 2000.

Acquired C1 esterase inhibitor deficiency is a rare condition associated with autoimmune or low-grade lymphoproliferative disorders. Adults or elderly patients are most commonly affected. The diagnosis is suspected when patients present with recurrent angioedema and low serum levels of C4 with normal levels of C3. Low levels of C1q and low C1 esterase inhibitor activity confirm the diagnosis.

In this paper, we summarize experience with 22 cases of acquired C1 esterase inhibitor deficiency in the context of a review of the published literature on diagnosis and treatment of this condition.