Background and Aims The pathogenesis of primary biliary cirrhosis (PBC) is unknown. The role of cytokines such as tumor necrosis factor-α (TNF-α) and transforming growth factor-β (ΤGF-β), and the effect of ursodeoxycholic acid (UDCA) in modifying the cytokine environment in patients with PBC has remained largely unstudied. Our aims were to determine: (i) the relationship between serum levels of TNF-α and TGF-β and the severity of PBC; and (ii) the effects of UDCA therapy on TNF-α and TGF-β levels in patients with PBC.
Methods We studied 90 patients who had been treated with UDCA (53 patients) or placebo (37 patients) for 2 years as part of a randomized, double-blind, controlled trial. Patients were divided into histological stage I/II or stage III/IV disease. Serum TNF-α and TGF-β levels were quantified by enzyme-linked immunoabsorbent assay.
Results Baseline levels of TNF-α were significantly greater in patients with stage III/IV compared to stage I/II disease. After 2 years of treatment with UDCA, patients showed a significantly greater decrease in TNF-α levels and progression risk score compared to placebo-treated patients. TNF-α and TGF-β levels were significantly reduced compared to baseline levels in the UDCA-treated group after 2 years, while there was no significant change in the levels of placebo-treated patients.
Conclusions Serum TNF-α and TGF-β levels may reflect severity of disease in patients with PBC. The beneficial effects of UDCA therapy may be explained by lowering serum levels of these two cytokines.