RESUMO
Scleroderma is a connective tissue disorder characterized by vascular lesions, fibrosis and inflammation. The pathogenesis of this disease is not clear. A vascular lesion, possibly caused by deposition of immune complexes or by release of cytotoxic factors, seems to be at the origin of the disease. As a consequence, platelet adhesion and activation might occur in sclerodermic patients. The observation that platelet might release, upon aggregation, a potent mitogenic factor, named Platelet Derived Growth Factor (PDGF) has focused interest on platelets as the potential mediators of the fibrotic process, characteristic of systemic scleroderma. We found an increased mitogenic activity in plasma derived serum (PDS) of a group of patients with progressive systemic sclerosis (PSS), as compared to control subjects. The activity was inhibited by incubation with anti-PDGF IgG's, suggesting that abnormal PDGF levels might indeed be present in plasma of PSS patients.