PROCESSING OF INTERLEUKIN-1-BETA IN SYNOVIAL-CELLS FRESHLY ISOLATED FROM PATIENTS WITH RHEUMATOID-ARTHRITIS

This study examined interleukin-1 beta (IL-1 beta) production by synov ial eels from patients with rheumatoid arthritis (RA). Freshly isolate d, plastic-adherent, synovial cells from ten of thirteen patients with RA secreted significant levels of IL-1 bioactivity, and the cells fro m five patients secreted more IL-1 beta bioactivity than IL-1 alpha bi oactivity. Further, there was a relatively good correlation between IL -1 beta bioactivity and IL-1 beta converting enzyme (ICE) activity sug gesting that bioactive IL-1 beta is possibly generated through the act ion of ICE. Analysis of metabolically-labeled IL-1 by sodium dodecyl s ulfate polyacrylamide gel electrophoresis (SDS-PAGE), however, indicat ed that, although these cells contained both pre IL-1 alpha and beta i ntracellularly, they secreted predominantly pre IL-1 beta. (C) 1994 Ac ademic Press, Inc.