136 ± 0.05 versus 0.09 ± 0.02 (× 106) (P = 0.0262) in CD20-treated mice versus controls and 0.64 ± 0.11 versus 0.27 ± 0.03 (×106) (P = 0.004) in CD79-treated mice versus controls; CD8+ CD62L− CD44+ cells, 0.14 ± 0.06 versus 0.05 ± 0.01 (× 106) (P = 0.0348) in CD20-treated mice versus controls and 0.362 ± 0.06 versus 0.158 ±

0.029 (× 106) (P = 0.007) in CD79-treated mice versus controls. As expected, there was no difference in the phenotypic distribution of mononuclear cells in the spleen (data not shown). ALT, AST, and ALP levels were measured to assess Torin 1 the correlation between serum biochemical values and histopathological abnormalities. As seen in Table 2, mice treated with anti-CD79 produced higher levels of ALT, AST, and ALP compared with that of control mice (P < 0.05). Mice treated with anti-CD20 demonstrated Daporinad mw a significant increase in AST levels only (P < 0.05). The levels of serum inflammatory cytokines in B cell–depleted mice were higher compared with control mice starting at 4 weeks of 2OA immunization (Fig.

6A). In particular, serum levels of IFN-γ in the CD20- and CD79-treated mice were significantly higher compared with sera from control mice (P = 0.046 and P = 0.011, respectively). Similarly, serum levels of MCP-1 in CD20- and CD79-treated mice were also significantly higher than sera from control mice (P = 0.0017 and P = 0.042, respectively) at 8 weeks after cholangitis induction. As expected, IL-10, in part secreted by B cells, was lower in B cell–depleted mice (Fig. 6B). We demonstrate herein that acute B cell depletion in mice with otherwise normal immune systems exacerbates cholangitis induction. Liver cell infiltrates from B cell–depleted mice contained increased populations of CD4+ and CD8+ T cells and activated counterparts and exhibited many increased serum levels of IFN-γ and MCP-1, but lower levels

of IL-10, compared with B cell–sufficient mice. These findings should be considered in the context of recent studies on the role of B cells in a genetic animal model of PBC, the dnTGF-βRII mouse.23 Anti-CD20 therapy in young dnTGF-βRII mice attenuates liver damage but exacerbates inflammatory bowel diseases; however, B cell depletion in older mice does not modify the course of liver disease.34 Importantly, double transgenic mice with PBC-like disease and B cell depletion (Igμ−/−dnTGF-βRII mice) developed a more severe form of cholangitis.24 The present study demonstrates that B cell depletion immediately before disease induction in the xenobiotic induced murine model enhances disease severity in the absence of AMAs, suggesting that B cells play a critical regulatory role in the breakdown of tolerance against PDC-E2.