Background: Anti-Fcγ receptor (anti-FcγR) autoantibodies occur in patients with systemic scleroderma. Their clinical significance is unknown.Objective: Our purpose was to determine the incidence of anti-FcγR autoantibodies in patients with localized and systemic scleroderma and to examine there lation between these autoantibodies, the severity of the disease, and the presence of other autoantibodies.Methods: Patients were placed into three clinical groups: three had diffuse systemic scleroderma, 47 had limited systemic scleroderma, and nine had localized systemic scleroderma. Antinuclear antibody titer and pattern were measured by indirect immunofluorescence with human epithelial (HEp)-2 cells and tissue sections, whereas anti-Scl-70 antibodies were measured by gel diffusion technique. Anti-FcγR autoantibodies were measured in serum from patients and from 25 healthy persons by enzyme-linked immunosorbent assay with human recombinant FcγRII (CD32) and FcγRIII (CD16).Results: Anti-FcγR autoantibodies were detected in 54% of patients and in none of the healthy control subjects. Autoantibodies were present in all three clinical groups and were most frequently directed against FcγRIII. Correlation between patients' clinical and laboratory data and anti-FcγR autoantibodies could not be demonstrated.Conclusion: The presence of anti-FcγR autoantibodies in the serum of patients with either systemic or localized scleroderma and the lack of these autoantibodies in healthy persons suggest that they may play a role in the pathogenesis of these diseases.