The purpose of this study is to learn more about new noninvasive ways of detecting lung disease in US Military personnel and people who worked as contractors during military operations in Iraq and Afghanistan. This study is looking at conducting a type of breathing test called the lung clearance index (LCI) test which is being investigated as a potential noninvasive way to detect the type of lung disease that may be seen in symptomatic deployers retuning from Iraq and Afghanistan.

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.

Inclusion Criteria:

For the deployer group:

• presence of respiratory symptoms (cough, chest tightness, wheezing, shortness of breath or decreased exercise tolerance) following deployment
• history of deployment for Operation Iraqi Freedom, Operation Enduring Freedom or Operation New Dawn for greater than or equal to 6 weeks as either military personnel or a civilian contractor
• prior VATS biopsy-proven histologic abnormalities of small airways disease.

For the control group:

• no history of pre-existing lung disease
• no respiratory illness in the four weeks preceding enrollment

Exclusion Criteria:

For the deployer group:

• If on clinical evaluation they were found to have asthma, vocal cord dysfunction or other explanations for their respiratory symptoms and did not need to undergo surgical lung biopsy for diagnosis.
• unable to provide informed consent
• pregnant subjects

For the control group:

• pre-existing lung disease
• unable to provide informed consent
• pregnant subjects

Symptomatic military deployers with deployment-related lung disease seen at National Jewish Health and healthy controls subjects.