Pathophysiological effects of endothelial cytotoxic activity derived from sera of patients with progressive systemic sclerosis.

Endothelial cytotoxic activity prepared from sera of patients with progressive systemic sclerosis (PSS) causes changes in endothelial cell physiology in vitro and in vivo. In the presence of endothelial cytotoxic activity human endothelial cell migration and fibronectin production in vitro were strongly reduced. Repeated intravenous injection of 1 ml partially purified endothelial cytotoxic activity IV once a week into rabbits caused a significant increase of serum FVIIIR: Ag, changes in endothelial cells morphology, and generalized dilatation of capillaries. Taken together, these results support the hypothesis that endothelial cytotoxic activity is a slow acting material which may initiate the obliterative vasculopathy in PSS by chronic damage of endothelial cells.