Elevated Levels of Circulating Platelet Aggregates and Beta-Thromboglobulin in Scleroderma

Abstract

Levels of circulating platelet aggregates and plasma β-thromboglobulin reflect the degree of platelet activation in vascular injury and repair. Both values were evaluated in 38 patients with scleroderma and 18 control subjects matched for age, sex, and race. Circulating platelet aggregates (expressed as percentage of total platelet count) were 7.2 ± 5.5% (mean ± SD) in the control group and 31.2 ± 13% in the scleroderma group (p < 0.0005). Beta-thromboglobulin levels in the control group were 20 ± 10 ng/mL and 72.7 ± 50 ng/mL in the group with scleroderma (p < 0.0005). A positive correlation was found between the two values (r = 0.6, p < 0.0005). Significant reductions in circulating platelet aggregates and β-thromboglobulin levels were achieved in 10 patients by dipyridamole and aspirin therapy. These results show in-vivo activation of platelets in scleroderma with release of platelet granule constituents. Antiplatelet therapy in adequate doses returned both values to normal; however, its long-term effect on scleroderma is not yet known.