Alpha-1-antitrypsin phenotypes in patients with ankylosing spondylitis

Alpha-1-antitrypsin (A1AT) is the most important plasma inhibitor of serine proteases present in numerous polymorphic varieties. It is suggested that phenotypes may be found more frequently in the connective tissue diseases. The purpose of our study was to determine individually the A1AT phenotype and to establish the prevalence rate of A1AT phenotypes in the serum of 52 patients with ankylosing spondylitis (AS). The preliminary analysis of the data indicates that a different prevalence pattern of A1AT phenotypes is found in patients with AS in comparison with a control group. The MM2 phenotype, which is responsible for both normal A1AT concentration in serum and its function, is less frequent in these patients. The deficit phenotypes causing abnormal A1AT concentration were not found in AS patients, which may be due to the relatively small number of patients.