Plasma levels of C1̄ inhibitor complexes and cleaved C1̄ inhibitor in patients with hereditary angioneurotic edema

Massimo Cugno, Jan Nuijens, Erik Hack, Anke Eerenberg, Donatella Frangi, Angelo Agostoni, Marco Cicardi

Research output: Contribution to journalArticlepeer-review

Abstract

C1̄ inhibitor (C1̄-Inh) catabolism in plasma of patients with hereditary angioneurotic edema (HANE) was assessed by measuring the complexes formed by C1̄-Inh with its target proteases (C1̄s, Factor XIIa, and kallikrein) and a modified (cleaved) inactive form of C1̄-Inh (iC1̄-Inh). This study was performed in plasma from 18 healthy subjects and 30 patients with HANE in remission: 20 with low antigen concentration (type I) and 10 (from 5 different kindreds) with dysfunctional protein (type II). Both type-I and type-II patients had increased C1̄-C1̄-Inh complexes (P <0.0001), which in type I inversely correlated with the levels of C1̄-Inh (P <0.001). iC1̄-Inh was normal in all type-I patients and in type-II patients from three families with increased C1̄-Inh antigen, whereas iC1̄-Inh was higher than 20 times the normal values in patients from the remaining two families with C1̄-Inh antigen in the normal range. None of the subjects had an increase of either Factor XIIa-C1̄-Inh or kallikrein-C1̄-Inh complexes. This study shows that the hypercatabolism of C1̄-Inh in HANE patients at least in part occurs via the formation of complexes with C1̄ and that genetically determined differences in catabolism of dysfunctional C1̄-Inh proteins are present in type-II patients.

Original languageEnglish
Pages (from-to)1215-1220
Number of pages6
JournalJournal of Clinical Investigation
Volume85
Issue number4
Publication statusPublished - Apr 1990

Keywords

  • C1̄ inhibitor catabolism
  • C1̄ inhibitor deficiency
  • Complement
  • Contact system
  • Dysfunctional C1̄ inhibitor

ASJC Scopus subject areas

  • Medicine(all)

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