TNF and arthritic joint disease: B10 cells, through IL-10 production, inhibit Th1 and Th17 cells and sustain/enhance Tregs and ameliorate experimental arthritis.1B10 cells also decrease activation of macrophages and dendritic cells and their tumor necrosis factor-α (TNFα) production2,3and the antigen-presenting capacity of dendritic cells,4thus decreasing proliferation of T cells (Figure 1).