A Simple Method for the Measurement of Different Forms of α 1 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 M_rs 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.