Mast cells and fibrosis. The relevance to scleroderma.

Mast cells are being recognized as important constituents in fibrotic processes. This article reviews the evidence for increased mast cell numbers and/or function in a variety of fibrotic conditions. Increased mast cell numbers and activity are seen in chronic murine graft-versus-host disease (a model for scleroderma) and in active scleroderma itself. An integrated schema for scleroderma is presented, emphasizing the interactions among mast cells, endothelial cells, and fibroblasts mediated by heparin and heparin-binding growth factors.