 3b. To test the hypothesis that local inflammatory responses and proteases are upregulated in HIV subjects with emphysema. BAL cellular infiltration will be characterized by flow cytometry to develop a quantitative and qualitative evaluation of cellular inflammatory responses in the four patient groups in Aim 3a. Lymphocyte populations will be analyzed for activation markers and intra-cellular cytokine production. The investigators will measure cytokine expression and protease levels in BAL supernatant as well as macrophage protease production. The investigators will compare results between groups and correlate with infections and HIV BAL viral levels. 