CCL5 and Arthritis: Of the genes that were differentially expressed under Breg-polarizing conditions (Figure 4B), pro-inflammatory cytokines including Il6, Tnf, Il2, and chemokines such as Ccl3, Ccl5, and Cxcl16, known to recruit lymphocytes to the inflamed synovia in models of arthritis (Kasama et al., 1995, Ruth et al., 2006, Szekanecz et al., 2000, Thornton et al., 1999), were upregulated in the absence of AhR (Figure 4D).