A Simple Method for the Measurement of Different Forms of α1 Proteinase Inhibitor in the Faeces of Patients with Crohn's Disease

Abstract

Alpha-1 proteinase inhibitor (α1PI), formerly named α1-antitrypsin, is excreted in the faeces of patients with Crohn's disease as isoforms clearly separated by SDS-PAGE and immunoblot analysis. Relapses in Crohn's disease are generally associated with the appearance in faeces of Mrs 51 000 and 45 000 glycosylated forms of α1PI, as compared with normal subjects and most of the patients in quiescent phases of their disease who excrete an M r 38 000 unglycosylated form of α1PI. We used their differential Concanavalin-A reactivity to design a specific test. The proposed assay is potentially helpful for the follow-up of patients under therapy and for early recognition of attacks of Crohn's disease.