Kveim antigen: what does it tell us about causation of sarcoidosis?

This article explores the role of the Kveim-Siltzbach (KS) test in finding the cause of sarcoidosis. Experimental granulomas are formed by a T-cell mediated immunologic response to particulate agents which resist degradation and persist in tissues for prolonged periods. There is no animal model for human sarcoidosis. However, the KS test is an in vivo model of sarcoidosis. KS homogenates incite a tissue response in patients with sarcoidosis histologically identical to disease-caused granulomas. The suspensions are particulate and maintain activity when exposed to a variety of chemical and physical stresses. Studies of the monocyte and T-cell host response confirm that KS reagent provokes a sarcoidosis-like antigen driven granuloma. KS suspensions contain an antigen(s) that incite a granuloma identical with that occurring in sarcoidosis. Identification of the active principle in KS suspensions should aid in the search for the cause of sarcoidosis.