Nonetheless, taken together our results support previous published work that Tregs, IL-10 and TGF-β play a significant role in the arthritis [16,17,18,19] and our findings, along with decreased numbers of inflammatory Th1 and Th17 cells, can explain, at least in part, the amelioration of the endogenous arthritis by rFc-μTP-L309C in our K/BxN mouse model. Here, TGFB1 is linked to arthritic joint disease.