[A case report of typical scleroderma accompanied with serum abnormalities characteristic of SLE during the course]

A 40-year-old woman had complained of cyanosis induced by cold exposure from the age of 26. When she was 32 years old, Raynaud's phenomenon occurred. She developed diffuse cutaneous sclerosis affecting the upper limbs, face and trunk, digital pitting scar, flexion contractures of hands, dilatation of lower esophagus and pulmonary fibrosis, and she was diagnosed as scleroderma. Laboratory findings revealed positive anti-topoisomerase I antibody and hypergammaglobulinemia (IgG 2,782, IgA 632, IgM 146 mg/dl). However, serum complement levels were normal and anti-DNA antibodies measured by radioimmunoassay (RIA) were negative. Initial dose of oral prednisolone was 30 mg/day and afterwards 5 mg/day of prednisolone was maintained. At the age of 36, scleroderma and contraction of hands were progressed, and telangiectasias appeared on her chest at the age of 36. Laboratory tests revealed hypocomplementemia (C3 27, C4 9 mg/dl, CH50 16 U/ml) and high titers, more than 100 U/ml, of anti-DNA antibodies measured by RIA. Clinical evidence suggestive of SLE could not be found. Reexamination of previous sera by enzyme immunoassay, in which anti-DNA antibody could not be detected by RIA, clarified the presence of IgG anti-dsDNA antibodies. It was considered that there existed low avidity/affinity of anti-dsDNA antibodies at first, and afterwards high avidity/affinity of anti-dsDNA antibodies appeared. Increasing of oral prednisolone up to 30 mg/day normalized serum complements and decreased titers of anti-DNA antibodies. She had not developed any clinical evidence that suspected SLE throughout the course.