Characterization of Tissue-Specific Immune Responses to Bronchoscopic Instillation of Mycobacterial Antigens Into the Human Lung

Background: Tuberculosis (TB) is a lung disease. It is caused by inhaling a type of airborne bacterium. Tuberculin Purified Protein Derivative (PPD) is used to test for TB exposure. It is usually injected under a person s skin. In this study, it will be applied in the lung. Objective: To learn how the cells within the lung react (immune response) when exposed to PPD. Eligibility: Adults ages 18-64 who (1) have been exposed to TB but do not have active disease or symptoms or (2) have never been exposed to TB. Design: Participants will be screened with a medical history, physical exam, and blood tests. They will have a TB skin test. They will also have an electrocardiogram to examine heart rhythm. For this, sticky patches will be placed on their chest. Some screening tests will be repeated at study visits. Participants will have 3 FDG PET-CT scans. They will lie in a machine that creates pictures of the inside of their body. They will get a radioactive substance injected into their arm called 18FDG. It helps make the pictures. Participants will have 3 bronchoscopies. Their mouth and nasal airways will be numbed. They will get drugs to relax. A tube will be inserted through their nose or mouth into a lung. Fluid will be delivered into the lung and suctioned back out to collect cells. They will get PPD during the first bronchoscopy. Participation will last for about 30 days. Participants will visit the clinic up to 8 times. They will go home after each procedure. No hospital stays are needed....