Fine structural capillary changes and basal lamina thickening in scleroderma (progressive systemic sclerosis) and Raynaud's disease.

Capillary abnormalities were found by electron microscopy in labial salivary gland biopsies obtained from 20 patients with progressive systemic sclerosis (PSS). They consisted of marked thickening and multilayering of basal lamina, degenerative and adaptative endothelial cell changes, alterations of pericytes and perivascular mononuclear cell infiltration. There was no correlationship between the intensity of the capillary abnormalities and the duration of the disease. In 12 patients with Raynaud's disease (RD) such changes were not found. Thus capillaries displayed normal-looking ultrastructural appearances. Mean capillary basal lamina width was consistently thicker in the PSS group than in the RD group (p less than 0.001). These observations are consistent with the hypothesis that the primary event in PSS occurs in the microvessels. It is suggested that labial salivary gland biopsy may be helpful for early recognition of PSS among subjects with Raynaud's syndrome.