Abstract
We aimed to assess expression of genes encoding the heterodimeric IL-27 cytokine and constituent subunits of the Il-27 receptor in rheumatoid arthritis (RA), including in extra-articular, subcutaneous rheumatoid nodules. Comparing between nodules and joint synovia, significantly elevated expression ofIL27Awithin nodules, and comparableIL27Bexpression, identified nodules as a significant source of IL-27 in RA. T-lymphocytes were the main source ofIL27RAtranscript, andIL27RAexpression correlated with a number of plasma cytokines, as well as tissueTNFexpression in both nodules and RA synovia. In synovia, correlations betweenIL27A,IL27RA IL17AandCD21Lexpression, and significantly elevated expression of the genes encoding IL-27, associated the presence of IL-27 with B cell-dominated synovial inflammation. Impact from nodule derived IL-27 on systemic or synovial inflammation in RA remains unknown and further study of these implications is required. Our study raises questions regarding the appropriate circumstances for the blockade or administration of IL-27 as a potential therapeutic adjunct in RA.