1. Filterability (deformability) of erythrocytes of patients with Raynaud's phenomenon together with progressive systemic sclerosis (PSS) was decreased compared with the filtration of erythrocytes from normal subjects.
2. PSS erythrocytes showed lower electrophoretic velocity and about 23% less neuraminidase-removable sialic acid density on their surface than the normal erythrocytes.
3. PSS erythrocytes showed more adherence to cultured endothelial cells than the control normal erythrocytes.
4. It is concluded that the increased rigidity and adherence of PSS erythrocytes-5-have pathological significance in the mechanism of vascular abnormalities in PSS.