Design of A Case Control Etiologic Study of Sarcoidosis (ACCESS)

Sarcoidosis is a chronic granulomatous disorder of unknown cause, character ized by activation of T-lymphocytes and macrophages. A Case Control Etiolog ic Study of Sarcoidosis (ACCESS) is a multicenter study designed to determi ne the etiology of sarcoidosis. The study organization includes 10 Clinical Centers, a Clinical Coordinating Center, specialized Core Laboratories, a Central Specimen Repository, and a Project Office at the National Heart, Lu ng, and Blood Institute. In addition to etiology, ACCESS will examine the s ocioeconomic status and clinical course of patients with sarcoidosis. We pr opose to enroll 720 newly diagnosed cases of sarcoidosis and compare them t o 720 age, sex, and race matched controls and follow the first 240 cases fo r two years. Leads to the etiology of sarcoidosis have come from diverse sources: in cli nical laboratory investigations, alveolitis has been found to precede granu lomatous inflammation; in case control studies, familial aggregation has be en identified; and in case reports, recurrence of granulomatous inflammatio n has been observed after lung transplantation. We describe the rationale f or the study design based on genetic, environmental, infectious, and immune dysregulation hypotheses and the methods used for selecting controls. The cause may not prove to be a single, known exposure. Interactions of exp osures with genetic predispositions would have important implications for o ur understanding of immune responses as well as the pathogenesis of sarcoid osis. (C) 1999 Elsevier Science Inc.