The study population will include all patients undergoing bronchoscopy for clinical indications at the Clinical Center who provide informed consent for chart review and proteomic analysis of BAL supernatant, as described in this protocol. We hope to acquire BAL samples that reflect a spectrum of community-acquired and opportunistic pathogens associated with pulmonary disease. In addition analysis of a range of non-infectious pulmonary processes (e.g. acute lung injury, acute respiratory distress syndrome and engraftment syndrome) is important to develop measures of sensitivity and specificity.