Alpha1-antichymotrypsin in rheumatoid arthritis.

Serum alpha1-antichymotrypsin (alpha1-ACT) of the patient with rheumatoid arthritis was studied by means of single radial immunodiffusion method. There was a significant elevation of the alpha1-ACT concentration in the patients with rheumatoid arthritis, and positive relationships were observed between the concentrations of alpha1-ACT and of other glycoproteins such as alpha1-acid glycoprotein and alpha1-antitrypsin in individual patients, and between C-reactive protein (CRP) rates and the (CRP) rates and the alpha1-ACT concentrations in individual specimens. These facts suggest that alpha1-ACT belongs to a group of acute phase proteins like alpha1-antitrypsin or CRP. An inverse proportional correlation was revealed between alpha1-ACT and fibrinolytic activity. No influences were observed on the alpha1-ACT concentration, activity index or articular index by the oral administration of alpha-chymotrypsin in patients with rheumatoid arthritis.