This study is being done to examine lung function changes in individuals with HIV infection and to understand why individuals with HIV have increased risk of lung damage from cigarette smoking.

To delineate the natural history of HIV associated emphysema in the HAART era. To compare the alveolar macrophage proteomes from HIV-seropositive smokers with emphysema to the alveolar macrophages proteomes of both HIV+ smokers without emphysema and HIV- smokers.

To establish whether coinfection with HIV and Hepatitis C results in accelerated lung disease manifested by decrements in forced expiratory volume and carbon monoxide diffusing capacity.

Inclusion Criteria:

• Clinically stable HIV-seropositive (and HIV-seronegative) individuals
• Ages 18 years and older
• Female subjects on no oral contraception with a negative pregnancy test
• Subjects capable of giving written consent

Exclusion Criteria:

• Known medical illness that would preclude bronchoscopy/BAL (e.g. unstable angina, new cardiac arrhythmia). This only pertains to subjects involved in the bronchoscopy phase of the study.
• Pregnant females
• Prisoners

community sample