IL-10 producing B cells regulate sex bias in male mice with experimental immune-mediated drug-induced hepatitis

Abstract

Abstract Sex modulates severity in autoimmune diseases. In susceptible individuals, drug metabolites induce hepatitis, autoimmunity and liver injury. This drug–induced hepatitis is a leading cause of liver failure and is the most common reason an approved medication is removed from the consumer market. We modeled this hepatitis in BALB/c mice and showed that estrogen and IL-6 increase severity and down-regulate IL-10 and Foxp3+ regulatory T cells; however, additional regulatory cells have not been identified. We induced experimental hepatitis in female and male CD1d−/− mice (NKT and CD1d+B cell-deficient), JH−/− (mature B cell and IgG deficient) and BALB/c (WT) mice by immunizing them with a cytochrome P4502E1 (CYP2E1) epitope (JHDN5) modified by a drug metabolite. Mice were evaluated for CFSE proliferation to drug metabolites as well as CYP2E1 and JHDN5, hepatitis and cytokines by ELISA. CD1d and B cell deficiency abolished sex bias. Male CD1d −/− mice developed more hepatitis than male WT mice (p<0.05); however these mice were also deficient in NKT cells as well as B cells expressing CD1d. Even though CFSE proliferation was 50% of male WT, male JH−/− mice developed more severe hepatitis (p<0.05) and higher TGF-β (p<0.01) levels than male WT. In contrast, IL-10 and IL-17 levels were up-regulated in male WT mice (p<0.05). Prior studies show that IL-17 promotes B cell help in immune responses, while IL-10 supports regulatory T and B cells. Our studies suggest regulatory roles for B cells in male mice and preliminarily suggest regulatory roles for CD1d expression on B cells in the development of sex bias in drug-induced hepatitis. We are currently characterizing B cells to determine their therapeutic potential in drug-induced hepatitis.