The registry consisted of a clinical coordinating center, 37 participating clinical centers that contributed patient data to the registry, a steering committee, and a data analysis and policy board, both appointed by the National Heart, Lung, and Blood Institute. Data collected on all patients included a clinical history, laboratory evaluations such as chest x-ray, lung function studies of vital capacity, total lung capacity, forced expiratory volume in one second (FEV1) and blood studies. In addition, patients receiving replacement therapy had baseline lung function tests, spirometry every six months following initiation of replacement therapy, and measurements of serum alpha1-antitrypsin level pre- and post-infusion, once every six months. The recruitment phase ended in September 1990. Support for the registry ended in June, 1998.