We use a procedure called a Bronchoscopy, and bronchoalveolar lavage, to obtain samples of Alveolar Macrophages (the key immune cell that is resident within the lung). This is a relatively common, routine medical procedure performed by respiratory and intensive care specialists. It is most commonly performed to aid in the diagnosis of lung infections and diseases. A bronchoscopy involves a thin, flexible plastic tube (scope) being passed via the nose or mouth into the lungs. A fibre-optic camera on the scope allows the medical team to see inside your lungs, and there are small ports on the scope that enable the team to take samples. Bronchoscopy is very safe and is generally performed as a day-case procedure under either very light sedation or by simply using a numbing spray on your throat. The most simple investigation performed by bronchoscopy involves taking washings from the lungs using salty water, termed a bronchoalveolar lavage or BAL. This salty water (saline) is then sucked back up into a sample pot through the scope. This is how we will obtain Alveolar Macrophages for laboratory analysis.