The healthy control group will comprise volunteers who are at least 18 years of age, have no history of pre-existing lung disease, and report no respiratory illness in the four weeks preceding enrollment.
The symptomatic deployers who have undergone lung biopsy and meet the case definition for deployment-related lung disease. A case of deployment-related lung disease is defined as the presence of unexplained chest symptoms in a deployer who, on a surgical lung biopsy, is found to have bronchiolitis or granulomatous pneumonitis without other known cause.