Ultrastructure of cutaneous cellular infiltrates in scleroderma.

Electron microscopy of the skin was performed in ten patients with systemic and four with localized scleroderma. The following three groups of cells were identified: (1) mature lymphocytes, T lymphoblasts, immature plasma cells, and plasma cells; (2) fibroblasts, fibrocytes, and fibroblast-like cells; and (3) macrophages, undifferentiated mesenchymal cells, and monocytes. Inthose specimens with mononuclear cell infiltrates, the most common cells were lymphocytic-types, macrophages, and fibroblasts with well developed rough endoplasmic reticulum. In the specimens at the fibrotic stage, fibroblasts and histiocytic-type cells predominated. This study suggests that cellular and humoral immunity may play a role in the pathophysiology of scleroderma.