Introduction Primary biliary cirrhosis (PBC) is a classic T cell mediated autoimmune disease: an autoantigen has been described and high levels of antigen specific liver infiltrating auto-reactive CD4+ T cells found. However, unlike in other autoimmune conditions steroid therapy is not considered effective in PBC although there is existing evidence that it can improve histological and biochemical parameters.1 We sought further evidence that PBC is a steroid sensitive disease by using two in vitro measures of steroid sensitivity.
Methods We have applied an in vitro dexamethasone (Dex) inhibition of lymphocyte proliferation assay (DILPA), which correlates well with clinical steroid sensitivity and outcome in ulcerative colitis2 and alcoholic hepatitis,3 to 20 patients with PBC diagnosed by liver biochemistry, antibodies and liver histology (when performed). The DILPA assesses peripheral blood mononuclear cell (PBMC) sensitivity to treatment with steroids in vitro. We also examined the role of CD14+ monocytes, which produce pro-inflammatory cytokines to recruit T cells to the tissue of inflammation. PBMCs were isolated from peripheral blood by density gradient centrifugation over Ficoll. CD14+ cells were obtained by positive microbead selection and cultured with 300 ng/ml lipopolysaccharide in the presence or absence of Dex 1×10−6M for 24 h. Supernatants were then collected and interleukin (IL)-1β, IL-6 and TNFα were measured by cytokine bead array (BD biosciences) according to manufacturer's instructions. Suppression of cytokine production by Dex was calculated.
Results In 20 patients with PBC, just one individual demonstrated in vitro steroid resistance by DILPA, and peripheral lymphocytes were sensitive to steroids in all other study subjects. Suppression of lymphocyte proliferation by Dex was significantly greater in patients with PBC compared to 37 healthy volunteer controls (86% vs 76%, p=0.04). Furthermore, Dex induced a 40%–100% suppression of IL-1β, IL-6 and TNFα (mean 75%, 74% and 79%, respectively) in the supernatants of CD14+ monocyte cultures. This suggests that both peripheral blood lymphocytes and monocytes in patients with PBC are steroid sensitive.
Conclusion Using a validated measure of lymphocyte steroid sensitivity and a further assessment of monocyte steroid sensitivity we have demonstrated that PBC is a steroid sensitive disease. Together with existing clinical studies of glucocorticoids in PBC1 our in vitro evidence suggests that steroid treatment should not be dismissed outright as it may provide a useful option in selected patients with PBC.
Competing interests None declared.
References 1. Mitchison HC, et al. Hepatology 1989;10:420–9.
2. Hearing SD, et al. Gut 1999;45;382–8.
3. di Mambro AJ, et al. Hepatology 2011;53:1316–22.
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