- Suspected subclinical Pneumocystis carinii infection as detected by > 10 percent change in lung volumes and/or diffusing capacity indicative of progressive restrictive disease as detected by monthly screening pulmonary function tests (PFT's). Patients will be afebrile and have no respiratory signs or symptoms of clinical disease. Morphologic confirmation of pneumocysts will be determined by bronchoalveolar lavage (BAL) performed 24 hours after the initial aerosol inhalation. If the BAL is negative for pneumocysts, the patient will be withdrawn from this protocol and will be followed per the screening PFT protocol at Stony Brook.