Kurimoto C et al. (2007) Thioredoxin may exert a protective effect against tissue damage caused by oxidative stress in salivary glands of patients with Sjögren's syndrome. J Rheumatol 34: 2035–2043

It has been suggested that oxidative stress has an important role in the pathogenesis of autoimmune diseases, including Sjögren's syndrome. Reactive oxygen species cause damage to DNA, which might lead to the generation of anti-DNA autoantibodies. The antioxidant protein thioredoxin protects against damage by reactive oxygen species, and also exhibits various immunological properties. Kurimoto and colleagues studied whether oxidative stress has a role in the pathogenesis of Sjögren's syndrome, and also whether thioredoxin has a protective effect against tissue damage caused by oxidative stress.

The study population included 29 female patients with Sjögren's syndrome, and a control group consisting of 22 patients with other rheumatic diseases (13 with rheumatoid arthritis, 9 with systemic lupus erythematosus) and 19 healthy individuals.

Higher levels of oxidative stress markers were observed in labial biopsy samples from patients with Sjögren's syndrome than from controls. Salivary levels of thioredoxin were also significantly higher in patients with Sjögren's syndrome than in controls, and high levels of thioredoxin expression were observed in acinar cells of 13 out of 19 patients. In vitro analysis showed that interferon-γ-induced IL-6 production was suppressed in thioredoxin-treated salivary gland cells, suggesting an anti-inflammatory effect of thioredoxin. Furthermore, Fas-mediated apoptosis seemed to be reduced in thioredoxin-treated salivary gland cells in vitro, which suggests that thioredoxin might have an anti-apoptotic effect.