With the aid of the GCRC, we at National Jewish (NJ) and at the National Institutes of Health (NIH) are investigating the etiology and clinical course of sarcoidosis. Sarcoidosis is a granulomatous disease of unknown origin. It occurs in people of all races and ages, although some research has suggested that it has a higher prevalence rate in African-American women and Northern European men and women, as well as 20 - 40 year olds. The respiratory system, the eyes, and skin are the organ systems which tend to be involved. Ten centers are participating in ACCESS. 720 cases and 720 matched controls will be enrolled within a 3 year period. The cases must be enrolled within 6 months of biopsy confirmation of sarcoidosis and for National Jewish, must reside in Colorado or parts of the surrounding states to participate. The controls are matched to cases on the basis of gender, race (white, black, or other), and +/- 5 years of age. The controls are recruited by random digit dialing method. The first 24 cases enrolled at each center are participating in the clinical course part of the study. Each of these cases will be asked to return to NJ 24 - 30 months after their baseline evaluation. National Jewish completed our first year of study enrollment in January, 1998. Participation for cases and controls involves an interviewer-administered questionnaire, and venipuncture for genetic testing of the blood. DNA analysis of the blood is performed at the Henry Ford Hospital lab in Detroit, Michigan. In addition, cases have a routine physical exam with Drs. Newman or Rose, P-A chest xray, and simple spirometry with pre- and post-bronchodialators. At the second evaluation for the 24 cases in the clinical course segment, we will administer another questionnaire, and repeat the baseline studies (spirometry with pre-and post-bronchodilator, chest xray, and routing physical exam). The GCRC nurses perform the spirometry and venipuncture when they are available and the GCRC lab manager packages and sends all blood specimens to the Henry Ford lab. We often use a GCRC room to administer the questionnaire. Enrollment began at our center on 11/15/96. To date, we have enrolled 32 cases and 29 controls into ACCESS. Data analysis will not be available until the conclusion of enrollment. A substudy under ACCESS, entitled "T Cell Stimulation in Sarcoidosis" (Brian Kotzin, M.D., P.I.), utilizes the BAL of patients with sarcoidosis from our center to determine the specificity of expanded CD4+ T cell clones. GCRC nurses assist in the performance of these bronchoscopies. The GCRC Core Immunology Laboratory performs lavage cell count, differential, T cell phenotyping, and catalogues and stores samples. Periodically this Core Lab sends slides to ACCESS. Five bronchoscopies have been performed for ACCESS. Two were subsequently not enrolled because they failed to meet ACCESS entry criteria.