TGFB1 and Arthritis: The requirement to understand the inflammatory context of TGF-β1 production is once again emphasised by conflicting findings on the impact (suppressive36 vs stimulatory37) of TGF-β1 on in vivo models of arthritis, where exogenous TGF-β1 treatment either exacerbated,38 39 alleviated40 or had no effect41 on disease severity.