Measurement of soluble proteins in lung secretions.

In performing its role as a gas exchanging organ the human lung constantly exposes a large surface area to the atmosphere, which contains particulate and chemical material either environmental in origin or self administered. There are several surface defences, however, that protect the lung from these potentially toxic substances; these include phagocytic cells, mucus, ciliated epithelium, and proteins such as the immunoglobulins and proteinase inhibitors.