The surface expression of intercellular adhesion molecule 1 (ICAM-1) and class I and class II major histocompatibility complex molecules on cultured dermal fibroblasts from 7 scleroderma patients and 6 control donors was compared. Scleroderma fibroblast lines contained 41.0 +/- 3.0% (mean +/- SEM) cells with high levels of ICAM-1 expression (ICAM-1-high), whereas 26.9 +/- 1.5% of control fibroblasts were ICAM-1-high (P = 0.0003). There were no differences in the expression of class I and class II molecules. ICAM-1-high and ICAM-1-low fibroblasts produced equal amounts of total protein and procollagen. The increase in the number of ICAM-1-high fibroblasts in scleroderma patients may facilitate T cell activation and lymphokine production, and thus indirectly contribute to the fibrotic process.