Objectives

To determine the etiology of sarcoidosis by establishing a case control, multi-center study. In addition to etiology, this study also sought to examine socioeconomic variables and the clinical course of patients with sarcoidosis, including quality of life.

Background

Sarcoidosis is a chronic granulomatous disorder of unknown cause that is characterized by activation of T-lymphocytes and macrophages. For many years sarcoidosis was presumed to be an atypical manifestation of tuberculosis because of the similarity between the inflammatory responses of the two diseases. However, as culture techniques became more widely employed to diagnose tuberculosis and it became less common, it became clear that sarcoidosis was not simply a variation of tuberculosis. Data on the etiology of sarcoidosis have come from diverse sources: in clinical investigations, alveolitis has been found to precede granulomatous inflammation; in case control studies, familial aggregation has been identified; and in case reports, recurrence of granulomatous inflammation has been observed after lung transplantation. The cause may not prove to be a single, known exposure. Interactions of exposures with genetic dispositions could have important implications for our understanding of immune responses as well as the pathogenesis of sarcoidosis.

Participants

736 patients with sarcoidosis enrolled within 6 months of diagnosis from 10 clinical centers in the U.S. Using the ACCESS sarcoidosis assessment system, organ involvement was determined for the whole group and for subgroups differentiated by sex, race, and age (<40 or 40 and older). Cases were matched with a control, and there was a two-year follow-up on cases. The ACCESS group proposed an instrument fo defining organ involvement in sarcoidosis. Biological specimens included DNA, plasma, and bronchoalveolar lavage samples were obtained. The data set includes 718 cases, 686 controls, and two-year follow-up data on 241 cases.

Conclusions

The initial presentation of sarcoidosis is related to sex, race and age, and it tends to remain stable over two years in the majority of patients. The etiology is probably multifactoral with both genetic and environmental factors contributing.

Specimen Details

The PBMC for this study are pelleted and suspended in guanidinium-based solution and are nonviable.

Additional Details

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