Differential diagnosis of scleroderma (progressive systemic sclerosis).

Scl-70 antibody is seen in 20% of patients with scleroderma, and in some patients with CREST syndrome (calcinosis, Raynaud, esophageal dysfunction, sclerodactyly, telangiectasia). These syndromes are also associated with a high frequency of speckled pattern immunofluorescent antinuclear antibody tests. Scl-70 may identify a subset of scleroderma patients with severe skin, joint, and lung disease. In addition, the presence of Scl-70 in Raynaud phenomenon may indicate a poor prognosis.