Anti-Single-Stranded DNA Antibody and Muscle Involvement in Localized Scleroderma

To the Editor.—  Localized scleroderma differs from systemic sclerosis because of the difference in the distribution of skin sclerosis and the lack of Raynaud's phenomenon, acrosclerosis, and internal involvement. In localized scleroderma, the lesions are usually limited to the skin and to the subcutaneous tissue beneath the cutaneous lesions. However, it has been suggested that the disease has an immunologic basis because the serum samples of patients frequently contain antinuclear antibody (ANA). Recent reports on ANAs by indirect immunofluorescence methods using monolayer cultured cells showed greater frequencies than those by previous standard tests using frozen tissue sections. We first reported that 72% of the patients with localized scleroderma have positive ANAs when HeLa cells served as the test substrate.¹ Recently, Falanga et al^2-4 have reported elevated levels of anti-single-stranded DNA (anti-ss-DNA) antibody in localized scleroderma. They have also shown a positive correlation between anti-ss-DNA antibody and joint contracture