Localized scleroderma is an autoimmune disorder

Objectives. There have been many studies suggesting that localized scleroderma has a strong autoimmune background, although the lesions are usually limited to the skin and subcutaneous tissue. Here we summarize previous data on the autoimmunity of localized scleroderma, mostly published in the last two decades, because there has not been a review paper summarizing autoimmunity in this disorder. Methods. We classified the previous reports into three categories: antinuclear antibodies; cytokine and soluble receptors; and cell adhesion molecules and cell surface molecules. In each category, we introduce the important investigations. Results. High frequencies of antinuclear antibodies, detected by the indirect immunofluorescence method using cultured cells, are confirmed by many groups. The major autoantigens have been revealed to be histones. Recently, anti-topoisomerase II alpha antibody has been found to be detected highly frequently in localized scleroderma, while anti-topoisomerase I antibody, which is highly specific for systemic sclerosis, has not been detected in any case of localized scleroderma. In other studies, elevated serum cytokines and cell adhesion molecules suggest the immunoactivation of localized scleroderma. Conclusions. Many previous studies conclude that localized scleroderma involves autoimmune abnormalities and is one of the organ-specific autoimmune disorders targeting mainly skin, although the types of autoimmune abnormality are different from systemic sclerosis.