Genomic Research in Alpha-1 Antitrypsin Deficiency

Alpha-1 Antitrypsin Deficiency (AATD, Alpha-1) is a genetic condition that predisposes to early onset pulmonary emphysema and airways obstruction, often indistinguishable from usual smoker's chronic obstructive pulmonary disease (COPD). Prominent features of AATD COPD include basilar predominant panacinar emphysema, frequent radiographic bronchiectasis, and a prominent interaction with environmental factors that influence clinical disease phenotypes. Alpha-1 antitrypsin (AAT) is the most abundant serum and lung antiprotease and has a variety of biologic activities that influence lung homeostasis. Prominent among these are roles in neutrophil elastase inhibition, antiprotease activities against cathepsins, involvement in the complement cascade, and interaction with toll receptors. Since the effects of AAT on lung homeostasis remain poorly understood, the Alpha-1 protocol for the Genomic Research in AAT Deficiency and Sarcoidosis (GRADS) grant (hereafter called GRADS Alpha-1 protocol) is designed to investigate the overarching hypothesis that alpha-1 antitrypsin (AAT) impacts the diversity and content of the lower airway microflora, resulting in a less inflammatory airway. Since the risk for bronchiectasis, COPD severity as measured by GOLD stage, and emphysema extent is proportional to the serum AAT concentration, comparison between different genotypes of AAT replete and deficient populations will provide data to determine if the diversity and content of the lower airway microflora influence the risk of COPD in the AATD population. The AATD population is selected because these individuals have a measurable interaction with environmental burdens22,28 and may be key to garnering an understanding of the interplay between this important anti-protease, airways and lower lung inflammation, peripheral blood gene expression, and radiologic and clinical phenotypes of COPD. The GRADS Alpha-1 Study is a prospective cross-sectional cohort study that will enroll approximately 200 participants at seven clinical centers with a total of nine recruitment locations over two years. An ancillary application to SPIROMICS will request data from 50 PiMM subjects, all (estimate 10) PiMZ subjects, and any (estimate 1) PiZZ subjects. The remainder of the participants (N=\~139) will be recruited through GRADS Alpha-1 centers. All participants will have two study-related visits (Baseline and Bronchoscopy). During the study visits, clinic staff will conduct physical examinations and tests, collect biological specimens, and administer a series of questionnaires to study participants. Participants could also receive a telephone call to determine the final status of any adverse event, 1 month after study conclusion.