Primary sclerosing cholangitis (PSC) is an autoimmune injury in which infiltrating T lymphocytes are implicated in bile duct destruction through an as yet, unknown mechanism. In July Gut, Bo and colleagues from the Karolinska Institute, Sweden, show that cell proliferation and the function of liver derived T lymphocytes is impaired in PSC patients as a consequence of chronic exposure to high levels of tumour necrosis factor α (TNF-α) in vivo.

Bo et al. studied the proliferative responses to common mitogens and the cytotoxic function of cell samples from patients with PSC, normal controls and from patients with other autoimmune liver diseases. In the supernatants of mitogen stimulated liver derived lymphocytes (LDLs) from patients with PSC there were significantly higher levels of TNF-α and IL-1β but lower levels of IL-2, IL-10 and interferon γ. In addition, pretreatment of PSC LDLs in vitro with neutralising TNF antibodies significantly enhanced...