Differences in red cell behaviour between patients with Raynaud's phenomenon and systemic sclerosis and patients with Raynaud's disease.

The 'filterability' and electrophoretic mobility of erythrocytes from 42 patients with systemic sclerosis and Raynaud's phenomenon were studied and compared with the findings from 24 patients with Raynaud's disease and 26 normal controls. Red blood cells from patients with systemic sclerosis and Raynaud's phenomenon were less filterable (P less than 0.0001) and had decreased electrophoretic mobility (P less than 0.001) compared with erythrocytes from patients with Raynaud's disease and the controls. There was no significant difference between the values from the patients with Raynaud's disease and the controls. These results indicate that measurement of erythrocyte filterability and electrophoretic mobility may be useful in the differentiation of patients with Raynaud's disease who have no underlying collagen disease from those who have Raynaud's phenomenon in association with systemic sclerosis.