Characterization of Apolipoprotein A-I Pathways in Idiopathic Pulmonary Fibrosis

Background: \- Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that becomes worse over time. There is currently no effective treatment for it. Researchers want to study the disease and learn new ways to treat it. Objectives: \- To discover new pathways that are involved in pulmonary fibrosis. To develop new drugs that may be used to treat pulmonary fibrosis. Eligibility: * People at least 18 years old with IPF. * Healthy volunteers at least 18 years old. Design: * Participants will be screened with medical history, questionnaire, and physical exam. They will have blood, lung, and walking tests and chest scans. * All participants will have 1 study visit, including: * Medical history and physical exam. * Questions about their breathing. * Blood tests. * Breathing tests. * Six-minute walk test. * Pregnancy test. * Chest x-ray (healthy volunteers) or chest CT scan (people with pulmonary fibrosis ). * Small area of skin may be removed. * Genetic tests of blood and skin samples. Participants will probably not be informed of any findings. Samples may be used to make stem cells for use in research. Participants may be contacted in the future to give consent for this research. * Some participants will have repeat visits over many years, repeating many of the study tests.