Excessive production of cytokines such as IL-6 and of chemokines such as CCL2 by fibroblasts or increased secretion of TGFbeta and PDGF by macrophages might be the consequence thereby contributing to excessive inflammation and/or a fibrotic reaction Such pathologic circuits have been described to contribute to diseases such as lung fibrosis, but might well be involved in synovial inflammation and synovial pannus formation during RA as well (90, 96). Here, IL6 is linked to rheumatoid arthritis.