Analysis of differentially regulated mRNAs in monocytic cells induced by in vitro stimulation with Kveim-Siltzbach test reagent.

Sarcoidosis is a granulomatous disorder of unknown origin. The sarcoid spleen-derived Kveim-Siltzbach test reagent (KSTR) elicits a sarcoid-specific, granulomatous response and was used to diagnose sarcoidosis. The active component and the pathomechanism by which KSTR induces granuloma are still unknown. This study investigated the KSTR-associated gene expression pattern in cells of patients with sarcoidosis or chronic beryllium disease (CBD). The monocytic-like cell line U937, alveolar macrophages of sarcoidosis patients, and peripheral blood monocytes of patients with CBD were stimulated with KSTR and other granuloma-associated stimuli. The KSTR-associated gene expression pattern was analyzed by means of differential display reverse transcription-polymerase chain reaction in combination with a multiple comparison of expressed sequence tags induced in response to KSTR and other granuloma-associated stimuli. Depending on the origin of cells tested, 3.7% to 14.6% of the analyzed sequence tags showed differential regulation induced by granuloma-associated stimuli. Alterations restricted to KSTR stimulation could be observed in 1.2% for the cell line U937, in 2.8% for blood monocytes of patients with CBD, and 1.3% for alveolar macrophages of sarcoidosis patients. These data are comparable to those achieved for the other granuloma-associated stimuli tested in this study. Therefore, it can be assumed that KSTR induces pathomechanisms for granuloma formation in sarcoidosis as beryllium in CBD.