Immune Response in Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) is an inflammatory lung disease that is caused by exposure of susceptible individuals to organic materials in the environment. It is also known by various names depending on the exposure and some of these names include farmer's lung, pigeon breeder's lung, hot tub lung to name a few. HP can cause lung scarring that impairs breathing and oxygenation. Early detection and avoidance of triggers can stop and reverse the disease but a significant number of patients continue to have active disease requiring treatment in spite of avoiding the trigger. The current choice of therapies is based on clinical experience and not on rigorous clinical trials. Not fully understanding the type of inflammation that is seen in HP and the cells involved in this inflammatory response limits health care providers' ability to choose drugs to study in HP that can stop the inflammation and limit scar formation. The goal of the investigators' study is to better understand the type of cells that are involved in the inflammatory response in the lungs of HP patients and what drives these cells to be active. By better understanding the type of cells and what drives them, health care providers can begin to choose and study drugs that can limit the inflammation and subsequent scarring. The investigators' will recruit HP patients and with their consent perform a scope of the lungs (bronchoscopy) with a limited lung wash to get the inflamed cells out of the lungs to further study them in the lab. The investigators' study will provide us with preliminary results to guide us in performing a more detailed study in the future to better understand the disease.