Progression activity for platelet-derived growth factor in plasma of patients with idiopathic thrombocytopenic purpura and aplastic anemia.

Progression activity for competence induced by platelet-derived growth factor (PDGF) was measured in plasma of patients with idiopathic thrombocytopenic purpura (ITP) and aplastic anemia (AA), in order to clarify the mechanism operating to maintain the wound healing system of these chronically thrombocytopenic patients. Progression activity in both ITP and AA patients was significantly higher than in normal subjects. There was a positive correlation between the activity and the duration of thrombocytopenia in AA patients who had thrombocytopenia for less than 100 months. The level of insulin like growth factor-I (IGF-I), which is a progression factor for PDGF, was lower in patients, than in normal controls. These results suggest that some plasma progression factor(s) for PDGF, other than IGF-I, plays an important role in maintaining the wound healing system of blood vessels in chronically thrombocytopenic patients.