An enzyme-linked immunosorbent assay and western immunoblotting analysis were used
to detect anti-platelet antibodies in the sera of 50 patients with systemic sclerosis.
Eleven (22%) positive sera were found by ELISA. Serial investigations showed that
the presence of these antibodies was often transient. Immunoblotting analysis demonstrated
that the antibodies were directed against a 114 kDa antigen. Using monoclonal antibody,
anti-platelet antibodies directed against gpIIIa were found in 4 cases. Similar to
immune thrombocytopenia and lupus erythematosus, a significant portion of the anti-platelet
antibodies were also directed against the glycoprotein complex IIb/IIIa in systemic