1. Using crossed immunoaffinity electrophoresis with free concanavalin A in the first dimension, we studied the microheterogeneity of α1-antichymotrypsin due to various glycoforms in sera from patients with various liver diseases and after liver transplantation.
2. Studies by isoelectric focusing and immunoblotting and by crossed immunoelectrophoresis without concanavalin A in the first dimension allowed us to show that there is no dramatic variation in electrophoretic heterogeneity of α1-antichymotrypsin in the serum of patients with liver diseases or after liver transplantation when compared with that of normal subjects. Therefore the heterogeneity observed in crossed immunoaffinity electrophoresis is due to various interactions with concanavalin A.
3. The results were expressed as the ratio of concanavalin A non-reactive glycoforms plus concanavalin A weakly reactive glycoforms to concanavalin A reactive glycoforms, called Rα1-ACT. Rα1-ACT was significantly higher in patients with cirrhosis (n = 53) when compared with normal subjects (n = 30). The median Rα1-ACT was 1 (range 0.72–1.25) in normal subjects. It was 1.6 (range 1.18–3.02), 1.45 (range 0.65–4.12) and 2.24 (range 1.03–19) in cirrhosis of Child's grade A, B and C, respectively. There was a dramatic decrease in glycoforms with mostly biantennary glycans in some patients with Child's grade C cirrhosis. Serum levels of α1-antichymotrypsin were lower than normal only in some patients with Child's grade C cirrhosis.
4. Among the patients with acute viral hepatitis studied (n=17), five were studied longitudinally. Rα1-ACT increased after the peak level of serum transaminases and remained high while the level of serum transaminases decreased and liver regeneration occurred. In these patients there was no alteration in glycoforms with mostly biantennary glycans.
5. Four patients were studied after liver transplantation. During the first days after transplantation Rα1-ACT was low because of an increase in glycoforms with mostly biantennary glycans. After the first week, Rα1-ACT rose above the normal range because of an increase in glycoforms with pluriantennary glycans and it returned to normal within 3 post-operative weeks. Rα1-ACT remained high in a patient who presented with liver rejection.
6. The present study suggests that Rα1-ACT is a helpful additional marker for the evaluation of hepatocyte function.