The importance of alpha-fodrin antibodies in the diagnosis of Sjögren’s syndrome
Our recent study suggested that the 120-kDa alpha-fodrin molecule may be an important autoantigen in the pathogenesis of Sjögren's syndrome, and anti-120-kDa alpha-fodrin antibodies have been detected in patients with Sjögren's syndrome. Here we have analyzed anti-120-kDa alpha-fodrin immune responses during development of spontaneous autoimmune sialadenitis in NOD mice as a model of Sjögren's syndrome. We found specific autoantibody production against 120-kDa alpha-fodrin, and its production correlated closely with autoimmune sialadenitis. A specific T cell response of splenocytes against the 120-kDa alpha-fodrin autoantigen was observed in NOD mice from the early onset of autoimmune sialadenitis. In addition, production in vitro by splenic T cells of cytokines such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), but not IL-4, was detected by enzyme-linked immunosorbent assays. We found up-regulation of local cytokine genes, including those of Th1 type (IL-1beta, TNF-alpha, IL-2, IFN-gamma, IL-6), as well as IL-10 and IL-12(p40), in the tissue-infiltrating cells during the course of autoimmune sialadenitis. These findings suggest that in spontaneous autoimmune sialadenitis in NOD mice, there may be a specific anti-120-kDa alpha-fodrin immune response in the development of autoimmune lesions resembling human Sjögren's syndrome, and that the autoreactive Th1 cells possess an up-regulated cytokine profile besides IL-10 and IL-12.